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Biomedical subjects

G Muzi

Publications and source records attributed to G Muzi.

At least 19 recordsLinked to original sources
PubMed2003

Primary DNA damage in chrome-plating workers.

In order to evaluate the primary DNA damage due to occupational exposure to chromium (VI), DNA strand-breaks and apoptosis in peripheral lymphocytes were measured in a group of 19 chrome-plating workers. DNA strand-breaks was assessed by alkaline (pH>13) single-cell microgel electrophoresis ('comet') assay, while apoptosis was measured by flow-cytometry after propidium iodide staining of the cells. Concentrations of chromium in urine, erythrocytes and lymphocytes were investigated as biological indicators of exposure. A group of 18 hospital workers (control group I) and another 20 university personnel (control group II) without exposure to chromium were also studied as controls. The results of the study show that chrome-plating workers have higher levels of chromium in urine, erythrocytes and lymphocytes than unexposed workers. Comet tail moment values, assumed as index of DNA damage, are increased in chromium-exposed workers and results are significantly correlated to chromium lymphocyte concentrations. No difference emerged in the percentage of apoptotic nuclei in exposed and unexposed workers. The study confirms that measurements of chromium in erythrocytes and lymphocytes may provide useful information about recent and past exposure to hexavalent chromium at the workplace. The increase in DNA strand-breaks measured by comet assay suggests this test is valid for the biological monitoring of workers exposed to genotoxic compounds such as chromium (VI).

Adult↗
PubMed2001

Yellow nail syndrome: does protein leakage play a role?

Yellow nail syndrome is characterized by primary lymphoedema, recurrent pleural effusion and yellow discoloration of the nails. Although mechanical lymphatic obstruction is assumed to be the underlying pathology, it cannot explain the common finding of high albumin concentration in the pleural space. This paper describes a case of yellow nail syndrome presenting with the classical triad of lymphoedema, recurrent pleural effusion and yellow discoloration of the nails, associated with persistent hypoalbuminaemia and increased enteric loss of albumin. Based on the findings in this case and those in the literature, it is speculated that increased microvascular permeability may contribute to the pathogenesis of this syndrome.

Aged↗
PubMed2001

Silica and its antagonistic effects on transforming growth factor-beta in lung fibroblast extracellular matrix production.

BACKGROUND: Silicosis, a pneumoconiosis marked by interstitial pulmonary fibrosis, is caused by inhalation of free crystalline silica particles. When silica particles are injected into the lower lung, they are translocated across the epithelium into the interstitial space, where macrophage-derived growth factors affect lung fibroblast proliferation and collagen deposition. We hypothesized that silica may act directly on pulmonary fibroblasts modifying extracellular matrix (ECM) synthesis and that the effects of silica may be mediated by transforming growth factor-beta (TGFbeta) overproduction. METHODS: To test this hypothesis, we studied a human lung fibroblast cell line (WI-1003) exposed to silica in vitro. We investigated cell morphology by electron microscopic procedure, cell growth, collagen production, and glycosaminoglycans (GAG) composition by radiolabeled precursors. Cytokine and growth factor synthesis were evaluated by specific enzyme-linked immunoadsorbent assay kits and Northern blotting analysis. RESULTS: Pulmonary fibroblasts internalized silica particles without detectable cell damage. Silica directly stimulated collagen synthesis and decreased the amount of 3H-glucosamine-labeled GAG. Silica-treated fibroblasts secreted less TGFbeta than untreated controls, antagonized the stimulatory effect of TGFbeta on ECM synthesis, and reversed TGFbeta-induced inhibition of cell proliferation. Northern blotting analysis showed increased interleukin-1alpha (IL-1alpha) mRNA after silica treatment. IL-1alpha had no influence on collagen synthesis but increased the number of WI-1003 fibroblasts. CONCLUSIONS: These results support our hypothesis that lung fibroblasts are direct silica targets. However, contradicting our hypothesis, silica antagonized TGFbeta activities through a TGFbeta downregulation and an IL-1alpha upregulation. The complex pattern of TGFbeta and IL-1alpha regulation in pulmonary fibroblasts is imbalanced by silica exposure and might play a key role in silica-mediated pulmonary fibrosis.

Cell Division↗
PubMed2001

Bronchial epithelial cell matrix production in response to silica and basic fibroblast growth factor.

BACKGROUND: Previous studies show that macrophages, lung fibroblasts, and their soluble mediators are responsible for the onset and development of pulmonary fibrosis. This study was conducted to determine whether airway epithelial cells are also directly involved in response to fibrogenic agents and consequently in the pathogenesis of lung fibrosis. To verify the hypothesis, we determined whether silica acts directly on human bronchial epithelial cells by stimulating cytokine and growth factor release and by modifying matrix production. MATERIALS AND METHODS: An SV40 large T antigen-transformed human airway epithelial cell line, 16HBE14o (16HBE), was used. The expression profile of some proinflammatory interleukins (ILs), such as IL-1alpha, IL-1beta and IL-6 and their modulation by silica, were evaluated by polymerase chain reaction (PCR) analysis. Transforming growth factor beta (TGFbeta) and basic fibroblast growth factor (bFGF) mRNA levels were tested by Northern blotting in the presence and in the absence of silica. The silica- and/or bFGF-induced effects on matrix components (total proteins, collagen, and fibronectin) were also evaluated using radio-labeled precursors. RESULTS: The results demonstrated 16HBE internalized silica particles. Silica induced a little IL-6 secretion, without affecting IL-1 and TGFbeta isoform production and strongly stimulated bFGF mRNA level and bFGF protein secretion. Silica also induced changes in 16HBE production of total proteins, collagen, and fibronectin production. When added in combination with the growth factor, it strengthened bFGF stimulation of matrix component secretion. CONCLUSIONS: These results support the hypothesis that the changes in matrix components are due to a direct effect of silica on bronchial epithelial cells. Silica-induced over-secretion of bFGF suggests that autocrine and paracrine differentiation loops for bFGF may also be operative and that these mechanisms may be involved in the pathogenesis of pulmonary fibrosis. In the future, cytokine-directed therapeutic strategies might find a place in clinical practice.

Blotting, Northern↗
PubMed2000

Activity and isoenzyme profile of N-acetyl-beta-D-glucosaminidase in urine from workers exposed to cadmium.

The urinary excretion of N-acetyl-beta-D-glucosaminidase (U-NAG) and urinary Cadmium (U-Cd) concentration, a measure of the metal load in the body, were evaluated in 28 workers exposed to Cd, to determine the relation between the two parameters. In urine from 22 exposed workers with U-Cd<2 microg/g creatinine (Cr) there was no significant difference in U-NAG value (0.98+/-0.59 U/gCr) compared to non-exposed (0.73+/-0.48 U/gCr). In the six workers with 2 microg/gCr < or =U-Cd<10 microg/gCr the U-NAG (2.32+/-0.61 U/gCr) was statistically (P<0.05) higher than in other workers. In both the U-Cd intervals examined there were no altered values of beta2-microglobulin from urine of exposed workers compared to non-exposed (<0.30 mg/l). The U-NAG isoenzymes were separated by DEAE-cellulose chromatography from urine of non-exposed subjects and exposed workers. The U-NAG isoenzyme profile in urine of non-exposed subjects showed a high percentage (about 95%) of the A (acid) form, a much lower percentage (about 4.5%) of B (basic) form and a negligible percentage (about 0.5%) of I (intermediate) form. In the urine of 22 exposed workers with U-Cd<2 microg/gCr, the percentages of U-NAG isoenzymes were not different from non-exposed. In the urine of six workers with 2 microg/gCr< or =U-Cd<10 microg/gCr the percentage (8.34+/-0.91) of isoenzyme B (U-NAG-B), a marker of lesional enzymuria, was statistically increased (P<0.05) compared to non-exposed (4.42+/-0.56). These results suggest that adopting a biological limit for U-Cd equal to 10 microg/gCr might not be sufficiently protective. The increase in U-NAG-B content at 2 microg/gCr<U-Cd</=10 microg/gCr is probably due to a lesion of the proximal tubule caused by the metal which might follow an induction of the apoptotic process.

Acetylglucosaminidase↗
PubMed1999

Blood cadmium concentrations in the general population of Umbria, central Italy.

The aims of this study were (a) to assess blood cadmium (B-Cd) concentrations and to establish a tentative reference interval; (b) to identify significant determinants of B-Cd, in a population from Umbria, Central Italy, which was not occupationally exposed to cadmium (Cd). Four hundred and thirty-four healthy blood-donors volunteered to answer a questionnaire and provide a blood sample for B-Cd analysis, which was performed by graphite furnace atomic absorption spectrophotometry. Blood Cd concentrations ranged from non-detectable values, i.e. below 0.1 microgram/l up to 3.4 micrograms/l and were not normally distributed. The median values and the 95th percentiles were 0.7 and 2.0 micrograms/l, respectively. Concentrations of B-Cd were more than double in smokers than in non-smokers, median values being 1.1 micrograms/l and 0.5 microgram/l, respectively. In current smokers, B-Cd values correlated with the number of cigarettes smoked daily (rs = 0.40, P = 0.0001) and with the cumulative exposure to cigarette smoke (rs = 0.35, P = 0.0001). Concentrations of B-Cd correlated with age in the non-smokers, but not in the smokers and were significantly higher in women than in men only in the non-smokers. Both in smokers and non-smokers, B-Cd concentrations were similar in subjects living in urban or in rural areas. In the whole study population the lower and the upper tentative reference limit were < 0.1 and 2.2 micrograms/l, respectively, as computed by a non-parametric rank-based method. The upper limit was approximately double in smokers than in non-smokers (3.1 micrograms/l and 1.6 micrograms/l, respectively). Our results show that B-Cd concentrations in a general population from Umbria are in the range reported for general populations in Northern Italy and other European Countries. Smoking was the strongest determinant of B-Cd concentrations and age had a lesser effect.

Adolescent↗
PubMed1998

Objective assessment of ocular and respiratory alterations in employees in a sick building.

BACKGROUND: Sick building syndrome (SBS) is a constellation of diffuse, "irritative" symptoms predominantly involving the eyes and the respiratory tract. To date, the effects of working in a "sick building" have not been adequately assessed using objective measures. We undertook the present study to determine whether objective alterations could be found in the eyes and respiratory' tracts of employees working in an office building in which a high rate of SBS had been reported in the preceding year. METHODS: We studied 163 office workers: 87 workers from a modern, air-conditioned building (the sick building), and 76 employees employed in three traditional-style office buildings (the comparison buildings). After being surveyed for SBS symptoms, all subjects underwent a series of objective tests, including spirometry, a methacholine test, prick tests for aeroallergens, and submitted tear samples. In addition, Schirmer's test and the break-up time test were used to explore for potential ocular effects of sick building exposure. RESULTS: Employees in the sick building complained more frequently of ocular symptoms, upper-airway disturbances, and general and respiratory' symptoms than did employees in the comparison buildings; prick tests were positive in 20% and 17.4%, respectively. Groups did not differ significantly on spirometry measures. Bronchial hyperreactivity to methacholine (PD15 = 16.348 mumol) was present in 20.5% of the sick building workers and in 16.2% of comparison buildings workers. Methacholine dose-response slope values were similar. Stability of tear film was significantly reduced (P < 0.01) in the employees in the sick building compared with employees in the comparison buildings. CONCLUSIONS: Our results indicate that (1) atopy does not seem to influence the prevalence of SBS symptoms, and (2) the lower respiratory tract seems unaffected by exposure to a "sick building," but (3) alterations in tear film stability do exist after such exposure.

Adult↗
PubMed1998

Prevalence of irritative symptoms in a nonproblem air-conditioned office building.

OBJECTIVES: To assess the prevalence of work-related complaints and symptoms in employees in an air-conditioned office building (Building AC) in a mild climatic area (Italy). No discomfort had previously been reported. METHODS: A total of 198 employees in Building AC and 281 controls working in three naturally ventilated buildings (Building NV) answered a questionnaire investigating work-related complaints and symptoms. RESULTS: A significantly higher percentage of workers in Building AC reported a lack of comfort in the working environment as compared with the controls (30.6% versus 18.9%). The most common complaints were strong lighting, high temperature, and dry, dusty, and/or stuffy air. The prevalence of ocular, upper airway, and cutaneous symptoms was significantly higher (29.8% versus 14.9%, 25.3% versus 9.6%, and 14.1% versus 3.6%, respectively). No significant difference was observed in respiratory or general symptoms. Logistic regression analysis showed that working with video display units and photocopiers influenced ocular symptoms; upper airway and cutaneous symptoms were influenced by female gender and working in the air-conditioned building. CONCLUSIONS: In an apparently healthy air-conditioned office building, complaints and symptoms are reported more often than in a naturally ventilated edifice, but the prevalence is lower than that usually observed in sick buildings. Symptoms are influenced by individual and work-related characteristics.

Adult↗
PubMed1998

Preventive measures reduce exposure to polycyclic aromatic hydrocarbons at a graphite electrode plant.

OBJECTIVE: This study assessed the efficacy of preventive measures in a graphite electrode plant aimed at reducing occupational exposure to polycyclic aromatic hydrocarbons (PAHs). METHODS: Electrode workers (n = 146) answered a questionnaire and provided an end of shift urine sample. Urinary 1-hydroxypyrene (1-hpur), a biological marker of exposure to PAHs, was measured by high performance liquid chromatography coupled with: (a) fluorescence detection. 1-Hydroxypyrene concentrations were compared with the concentrations measured before implementing the preventive measures; and (b) those of a control group of 54 men not occupationally exposed to PAHs. RESULTS: After implementation of preventive measures, median concentrations 1-hpur were significantly reduced in some groups of workers: by -24%, -37% and -30% in workers at the green electrode unit, one baking impregnation unit, and the laboratory, respectively. In workers at a second baking impregnation unit, in end product finishing and in the power station 1-hpur concentrations were unchanged. Urinary 1-hp concentrations were still significantly higher in each group of workers than in the control group (p < 0.001 for any comparison). Concentrations in the workers varied with the type of job, the highest values being found in workers engaged in the power station, in the two baking impregnation units and in the green electrode unit. CONCLUSIONS: Implementing preventive measures significantly reduced exposure to PAHs at a graphite electrode plant. The reduction in median and peak concentrations of 1-hpur, which reflects total exposure to, and internal dose of PAHs, was most evident in workers employed in the units where preventive measures had been taken. Despite an overall reduction, further preventive measures are needed to minimise exposure to PAHs and consequently the risk of adverse health effects.

Biomarkers↗
PubMed1998

[Lead absorption in an Umbrian population from 1982 to 1992].

This report assessed lead absorption in community samples of the general population in Umbria, central Italy, in 1982 and in 1992. Each participant (128 subjects in 1982 and 479 in 1992) answered a questionnaire providing details of personal information and life style. Blood lead levels were determined by atomic absorption spectrophotometry. In 1992 hematocrit and glutamyltranspeptidase (gamma-GT) levels were also measured. In 1982 the mean blood lead level was 226 micrograms/l in males and 167 micrograms/l in females, and in 1992 it was still higher in males than in females (98 micrograms/l vs 61 micrograms/l) as were hematocrit and gamma-GT levels. Multiple regression analysis showed sex and age were the main factors accounting for 42% of the total variation in blood lead levels. They were followed by alcohol consumption, gamma-GT levels and smoking in this order. In conclusion, blood lead levels decreased significantly in central Italy in the decade 1982-92 and persistent lead absorption seems to be due to individual characteristics such as male sex, advanced age and a personal life style which includes alcohol consumption and smoking.

Adult↗
PubMed1997

Long-term pulmonary and systemic toxicity following intravenous mercury injection.

Long-term pulmonary and systemic toxicity following mercury intravenous injection has rarely been assessed. We present the results of a detailed investigation assessing pulmonary and systemic long-term toxic effects in a subject who had pulmonary and systemic mercury microembolism diagnosed more than 11 years previously. Radiographic examination showed the persistence of mercury microemboli in both lungs and elsewhere in the body. Lung function tests revealed a decreased diffusing capacity for carbon monoxide and PO2 probably indicative of microscopic inflammation of lung interstitium. Electroneuromyography showed signs of mild axonopathy in both legs. At semen analysis, a high proportion of motionless spermatozoa was present. Urinary excretion of mercury was high. Signs of interstitial lung impairment, peripheral axonopathy and asthenozoospermia in a subject who had mercury microembolism persisting for more than 11 years might be evidence of long-term mercury toxicity.

Adult↗
PubMed1995

Bilateral median and ulnar neuropathy at the wrist in a parquet floorer.

Many cases of work related compression neuropathy of the ulnar and median nerves at the wrist have been described. This report presents a case of bilateral distal neuropathy of the median and ulnar nerves in a parquet floorer, who laid wooden block flooring by hand and used the palms and volar surface of both hands to hit the blocks into place. He also used an electric sander and polisher. Bilateral numbness and paraesthesias in all fingers had been present for about one year. Clinical examination was normal; the neurological assessment indicated slight impairment in response to tactile, heat, and pain stimuli in all 10 fingers. Electroneurography showed increased distal motor latencies of median and ulnar nerves at both wrists, although the lower limbs were normal. The results of blood, urine, and instrumental tests excluded systemic disease or local factors that could cause compression neuropathy. After stopping work for three months, the clinical picture and electroneurographic results improved. These data support the hypothesis that the damage to the median and ulnar nerves had been caused by the patient's way of working, which provoked repeated bilateral microtrauma to his wrists. To diagnose work related multiple neuropathy can be difficult and an accurate work history is necessary. Preventive measures and diligent health care are required for this category of worker.

Adult↗
PubMed1991

Reduced activities of key enzymes of gluconeogenesis as possible cause of acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rats.

Male Sprague--Dawley rats (350-375 g) were injected i.p. with TCDD (25 [sublethal dose] and 125 micrograms/kg [lethal dose], respectively, in corn oil/acetone), or vehicle only; vehicle-treated animals were pair-fed to their TCDD-treated counterparts. 1, 2, 4, 8, 16, and 32 days (28 days for lethal dose) thereafter, animals were sacrificed and activities of two key enzymes of gluconeogenesis determined in livers of rats. In livers of pair-fed rats both enzyme activities were little affected. In the livers of TCDD-treated animals the activity of phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.32) decreased rapidly, exhibiting significant losses by the 2nd day after treatment. Time course and extent of loss of PEPCK activity (about 50%) were similar after either dose. The activity of glucose-6-phosphatase (G-6-Pase, EC 3.1.3.9) decreased more slowly as a result of TCDD treatment; statistically significant losses were observed by 4 or 8 days after the lethal and sublethal dose, respectively. These results confirm the hypothesis that reduced in vivo rates of gluconeogenesis in TCDD-treated rats are due to decreased activities of gluconeogenic enzymes. In an additional set of experiments, rats were treated with 125 micrograms/kg TCDD, 25 micrograms/kg TCDD, or with vehicle alone. The 25 micrograms/kg or vehicle-treated rats were then pair-fed to rats dosed with 125 micrograms/kg of TCDD. Mean time to death and body weight loss at the time of death were essentially identical in all groups, lending additional support to the hypothesis that reduced feed intake is the major cause of TCDD-induced death in male Sprague--Dawley rats. Both appetite suppression and reduced total PEPCK activity in whole livers occurred in the same dose-ranges of TCDD, suggesting the possibility of a cause-effect relationship.

Animals↗
PubMed1989

Mode of metabolism is altered in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-treated rats.

Male Sprague-Dawley rats were fed either a high-fat (HF) or a high-carbohydrate (HC) diet and subsequently injected with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (125 micrograms/kg) or vehicle (pair-fed controls). In all TCDD-treated animals, a reduction in caloric intake was evident as early as 1 day after dosage. Respiratory quotients (RQ) were determined at 5-day intervals. Their pattern for the HC-fed but not for the HF-fed TCDD-treated rats was different from that of the corresponding pair-fed controls. After an initial parallel decrease the RQ values remained low for TCDD-treated rats whereas they increased again for pair-fed controls. Serum total thyroxine (T4) was significantly lower in TCDD-treated animals and this reduction was not influenced by the composition of the diet. Serum triiodothyronine (T3) was neither altered by diet nor by TCDD. Thymic atrophy was as severe in pair-fed as in TCDD-treated rats fed the HC diet but not in rats fed the HF diet. Our results suggest that TCDD-treated rats are in a different mode of metabolism from pair-fed rats and that this difference is related to gluconeogenesis.

Animals↗
PubMed1989

Effects of low doses of lead on children's health.

An investigation has been carried out of the blood lead levels of children resident in three different municipalities of Umbria: Corciano, selected as a control area; Perugia, the largest town in Umbria (approx. 150,000 inhabitants), with intense automobile traffic; and Deruta a town in which there is a flourishing ceramic industry. The mean blood lead levels were found to be higher in children in Perugia (96 micrograms/l) and Deruta (97 micrograms/l) with respect to Corciano (83 micrograms/l); in Deruta the mean blood levels were raised in those children whose families are occupationally exposed to lead (107 micrograms/l). The concentration of lead in the air in Deruta was higher than in Corciano (0.19 vs 0.11 microgram/m3, respectively). The lead concentrations in house dust were higher in Deruta (2.8 micrograms/m2) than in Corciano (0.8 microgram/m2) and the difference was greater in the houses were the inhabitants were exposed to lead in factories (2.7 micrograms/m2) or in workshops which were adjacent to the houses (4.7 micrograms/m2). The blood lead levels of children included in this study have been compared with those obtained during a similar investigation in 1978. Over the last eight years primary school children in Corciano and Deruta have shown a marked reduction in blood lead levels (greater than 50%). This improvement should not lead to false optimism: in fact, it is impossible to establish the blood lead level at which no adverse effects are induced, especially in children. Numerous studies suggest that even sub-clinical levels of lead can cause alteration in heme synthesis, peripheral nervous system, kidney, immune system, skeleton and growth. Furthermore, with regard to the central nervous system, low blood lead levels can provoke neuropsychological deficits, which can result above all, in a decreased I.Q., and behavioural alterations.

Air Pollutants↗
PubMed1988

Elevated plasma corticosterone levels and histopathology of the adrenals and thymuses in 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated rats.

The relationship between thymic atrophy and plasma corticosterone levels was examined in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-treated, pair-fed and ad libitum-fed male Sprague-Dawley rats given a usually lethal (125 micrograms/kg) or non-lethal (25 micrograms/kg) dose of TCDD. At both dosages, corticosterone levels in TCDD-treated animals begun to rise as early as day 4 after treatment. At later time points corticosterone levels were 5-7 times higher in rats given the non-lethal dose, and 6-10 times higher in rats administered the lethal dose than the levels observed in ad libitum-fed controls. Corticosterone levels in control rats pair-fed to the lethal dose group (as a result of the severe reduction in feed intake) were similarly elevated as in TCDD-treated rats but this was not the case in pair-fed rats of the non-lethal TCDD dosage (due to an essentially unchanged feed intake). At both dosages, relative thymus weights of TCDD-treated rats started decreasing by day 4 and continued to decline for the most part of the study. Relative thymus weights of rats pair-fed to the non-lethal TCDD dosage were not different from ad libitum-fed rats. However, the decrease in relative thymus weights of rats pair-fed to the lethal TCDD dosage paralleled that of TCDD-treated rats with an apparent 8-day lag period. Morphologically, the thymus as well as the adrenal revealed differential changes in TCDD-treated rats from those observable in pair-fed rats. These results suggest that either TCDD exerts a direct effect on the thymus and the adrenals or it causes an additional stress (e.g., a metabolic stress) over and above the starvation stress, which may be responsible for the differential morphological changes in these glands.

Adrenal Glands↗