Biomedical subjects
Publications and source records attributed to G Carelli.
In outdoor factory environments many defiling substances are produced by different working processes. Reclamation operations must, therefore, be directed to the single types of pollution involved. A series of corrective operations, aiming at the elimination of fumes, frinding powders, solvent vapours, paint pigments and hydrocarbon vapours, are described.
Total tissue water of rabbit plancenta decreases by 18% between the 9th day and the end of gestation. In the same period intracellular water decreases by 40% and the extracellular compartment swells. Total tissue sodium and chloride content increase by 34% and 27% respectively from the 16th to the 33rd day while potassium decreases by 30%. The intracellular concentration of these ions does not vary greatly during gestation. Moreover the total tissue magnesium content decreases by about 23% at the end of gestation while its intracellular concentration does not show marked changes. Calcium content of rabbit placenta substantially increases during gestation and intracellular calcium shows a fivefold increase from the 16th to the 33rd day of gestation. The results are discussed in terms of relation between water and ion content and placental tissue growth and aging.
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Previous investigations have shown that Pb exerts immunotoxic effects. Object of this study were Th1 and Th2-type immune responses of mice to Pb exposure. Adult Swiss male mice were administered 0, 40 and 400 mg/l of Pb (as acetate) in drinking water for 14 days. At the end of the treatment, blood Pb was determined and two Th1 cytokines (IL-2, INF-gamma) and one Th2 serum cytokine (IL-4) were measured. A significant increase in IL-4 production was observed in the mice exposed to 40 mg/l of Pb, while a further increase in IL-4 production was associated with a decrease in INF-gamma production in mice exposed to 400 mg/l of Pb. On the other hand, Pb exposure did not induce changes of serum IL-2 (involved also in the Th0 immune pattern). Our findings indicate that low level Pb exposure enhances a Th2 response. A high Pb does can either stimulate the Th2 immune activity or reduce the Th1 response; the result is an imbalance between Th1 and Th2 activation.
The effects on normal rat fibroblasts of lead supplementation (as lead acetate) in the medium were examined. The amount of lead acetate ranged from 0.078 microM to 320 microM, at 14 concentrations. The normal level of lead in the medium was 0.060 microM, and the normal concentration of lead in the fibroblasts was 3.1 +/- 0.1 ng/10(7) cells: these represented the control conditions. On studying fibroblast proliferation and survival after incubation for 48 hours, a lead acetate dose-dependent inhibition of cell proliferation was observed, the results being shown to be significant by ANOVA (p < 0.01), and suggesting a significant dose-response relationship. Apoptosis, evaluated by quantifying cytoplasmic DNA fragments, differs significantly between the lead levels tested. The distribution in the cell cycle, evaluated by using a fluorescence-activated cell sorter, showed a dose-dependent accumulation of cells in the G0/G1 phase, with a compensatory decrease in the percentage of cells in the S phase. Moreover, the occurrence of a subdiploid peak confirmed that apoptosis was more evident when the medium was supplemented with lead acetate at concentrations of 5-20 microM. The inhibition of cell growth is probably due to a direct inhibition of cell proliferation.
Over the past few decades there has been a gradual decline in concentrations of airborne chemical agents in the workplace. This improvement in the workplace has led to a concomitant need to study the effects of low dose exposure in order to assess possible risks. The paradigm used in toxicology to evaluate risk and to establish exposure limits for substances employed in industry, is that the dose-response relationship is expressed by a linear model for carcinogenic substances and by a threshold model for those which are not. Alongside these two traditional models, there has been a recent proposal to describe relationships using hormesis which is characterised by a biphasic curve corresponding to moderate stimulation resulting from response to low doses, and by inhibition at high doses. Although hormesis has been widely observed in experimental contexts, it still has to be tested in occupational toxicology to determine the possibility of obtaining a more accurate evaluation of the risk of exposure to low doses present in the workplace.
Iridium (Ir) is one of the six elements collectively known as the platinum group metals. For its excellent catalytic properties, Ir was recently introduced into DeNOx, a new generation of automotive catalysts. The aim of our study was to evaluate urinary Ir levels in an urban population. A total of 122 healthy male subjects of Rome (Italy) were studied. Ir quantification in the urine samples of these subjects was carried out by sector field inductively coupled plasma mass spectrometry. The mean urinary Ir level was 10.41 ng/g creatinine (standard deviation: 9.67; 25th-75th percentile: 3,62-12,74 ng/g creatinine). The scientific community should respond to a potential increase in environmental exposure to Ir, due to its growing use as a catalyst, with very careful evaluation of the biological levels of this metal and monitoring of airborne particulate present in the life environment. Further investigation will enable researchers to confirm and integrate the findings of our present study undertaken in the context of surveillance.
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Male Sprague-Dawley rats, who had received 50 micrograms/ml of arsenic (as sodium arsenate) in drinking water for 320 days, showed high urinary excretion of this element. Arsenic was accumulated in tissues, mostly in the kidney and in the liver. In the kidney were evident slight focal alterations in tubules and glameruli; some of the tubules contained casts of amorphous hyaline material. The hepatocytes close to the centrolobular veins were swollen and showed ultrastructural alterations. The seric GOT, GPT and LDH activities were normal, while the alkaline phosphatase alto have been found in the brain, sciatic nerve, lung, heart and arteries. No significant changes of systolic and diastolic blood pressure levels were observed. Similarly, cardiac inotropism and chronotropism were unchanged. The electrocardiogram, also, was normal. The cardiovascular reactivity to noradrenaline, acetylcholine, histamine, serotonin, bradykinin and angiotensin II was unchanged. However, the vascular reactivity to the beta-stimulation was increased, while it was decreased to the angiotensin I. On the whole, our results suggest that chronic arsenic exposure produces focal alterations in the kidney and characteristic modifications in the hepatic structure and in the cardiovascular reactivity.
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