Markers of oxidative damage of nucleic acids and proteins among workers exposed to TiO2 (nano) particles.

OBJECTIVE: The use of nanotechnology is growing enormously and occupational physicians have an increasing interest in evaluating potential hazards and finding biomarkers of effect in workers exposed to nanoparticles. METHODS: A study was carried out with 36 workers exposed to (nano)TiO2 pigment and 45 controls. Condensate (EBC) titanium and markers of oxidation of nucleic acids (including 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU)) and proteins (such as o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr) and 3-nitrotyrosine (3-NOTyr)) were analysed from samples of their exhaled breath. RESULTS: In the production workshops, the median total mass 2012 and 2013 TiO2 concentrations were 0.65 and 0.40 mg/m(3), respectively. The median numbers of concentrations measured by the scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) were 1.98 × 10(4) and 2.32 × 10(4) particles/cm(3), respectively; and about 80% of those particles were smaller than 100 nm in diameter. In the research workspace, lower aerosol concentrations (0.16 mg/m(3) and 1.32 × 10(4) particles/cm(3)) were found. Titanium in the EBC was significantly higher in production workers (p<0.001) than in research workers and unexposed controls. Accordingly, most EBC oxidative stress markers, including in the preshift samples, were higher in production workers than in the two other groups. Multiple regression analysis confirmed an association between the production of TiO2 and the levels of studied biomarkers. CONCLUSIONS: The concentration of titanium in EBC may serve as a direct exposure marker in workers producing TiO2 pigment; the markers of oxidative stress reflect the local biological effect of (nano)TiO2 in the respiratory tract of the exposed workers.

Hydroxyl radicals and oxidative stress: the dark side of Fe corrosion.

Fe-based materials are considered for the manufacture of temporary implants that degrade through the corrosion of Fe by oxygen. Here we document the generation of hydroxyl radicals (HO) during this corrosion process, and their deleterious impacts on human endothelial (ECs) and smooth muscle cells (SMCs) in vitro. The generation of HO was documented by two independent acellular assays, terephtalic acid hydroxylation (fluorescence) and spin trapping technique coupled with electron paramagnetic resonance spectroscopy. All Fe-based materials tested exhibited a strong potential to generate HO. The addition of catalase prevented the formation of HO. Cellular responses were assessed in two ECs and SMCs lines using different cytotoxicity assays (WST-1 and CellTiter-Glo). Cells were exposed directly to Fe powder in the presence/absence of catalase, or to extracts obtained from the corrosion of Fe. Cell viability was dose-dependently affected by the direct contact with Fe materials, but not in the presence of catalase or after indirect exposure to cell extracts. The deleterious effect of HO on ECs and SMCs was confirmed by the dose-dependent increase of the transcripts of the oxidative stress gene heme oxygenase-1 4 h or 6 h after direct exposure to the particles, but not in presence of catalase or after indirect exposure. The demonstration of HO production during corrosion and consequent oxidative stress on human ECs and SMCs newly reveals a deleterious consequence of Fe-corrosion that should be integrated in the assessment of the biocompatibility of Fe-based alloys.

Effect of ibopamine on the progression of chronic renal failure.

Persistent changes in the slope of the reciprocal of serum creatinine concentration against time after medical intervention are likely to reflect the influence of therapy on progression of chronic renal failure. This observation allowed us to demonstrate the ability of ibopamine, a new orally active dopamine-related drug, to improve renal function or at least to slow its deterioration in 20 patients studied over a period of 6 months. We also noted that the therapeutic response to the drug varied considerably according to the nature of the underlying nephropathy, with maximal benefit being observed in nonglomerular diseases.

Serum CA 19-9 and CA 50 antigens in hemodialysis patients.

Serum concentrations of monoclonal antibody-defined tumor markers CA 19-9 and CA 50 were measured in 64 uncomplicated hemodialysis patients (Group 1) and in 8 hemodialysis patients with cancer (Group 2) in comparison with corresponding CEA determinations. From our results in Group 1 patients it appears that both CA 19-9 and CA 50 maintained an excellent specificity in these patients. As to the sensitivity of these tests, our findings in Group 2 patients are comparable with those reported in patients with cancer and normal renal function. It is concluded that, unlike CEA, these new tumor markers maintain their clinical value in chronic renal failure.

Elevated acute phase reactants in hemodialysis patients.

The incidence of elevated acute phase reactants, measured by nephelometry, was examined in 69 otherwise uncomplicated hemodialysis patients in comparison with 30 healthy subjects. Increased C-reactive protein was found in 40.6% of the patients (p less than 0.001 vs controls) and the degree of increase was correlated with the duration of hemodialysis. Haptoglobin was increased in 33.3% (p less than 0.01 vs controls). High levels of alpha-1-acid glycoprotein and alpha-1-proteinase inhibitor were present in 15.9% and 2.9%, respectively; these frequencies were not significantly different from controls. No differences between pre- and postdialysis values were observed. It is concluded that, unlike C-reactive protein, both alpha-1-acid glycoprotein and alpha-1-proteinase inhibitor maintain an excellent specificity in hemodialysis patients. Vice versa, haptoglobin may be unreliable as an acute phase reactant in these patients because of the unacceptably high false-positive rate.

Osmotic fragility of erythrocytes, cell deformability and secondary hyperparathyroidism in uremic patients on maintenance hemodialysis.

The possible relationship between erythrocyte (RBC) function and secondary hyperparathyroidism (HPT) was examined in 35 uremic patients on maintenance hemodialysis. Mechanical tests (i.e., osmotic fragility and deformability) were used to assess RBC function. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (X-ray films of the hand skeleton). Sixteen sex and age-matched normal volunteers acted as controls. This study shows that the mechanical properties of RBC were indeed markedly altered in hemodialysis patients when compared with controls. No significant correlations between either the osmotic fragility or the deformability of RBC and the hematochemical changes associated with secondary HPT were found. No differences in RBC function tests were found as far as the activity (alkaline phosphatase) or the severity (X-ray findings) of secondary HPT are concerned. Effective treatment of secondary HPT by either pharmacological means (1,25-dihydroxycholecalciferol) or surgical removal was not associated with consequent improvement in RBC function. These findings clearly speak against secondary HPT as a major cause of RBC dysfunction in uremic patients on maintenance hemodialysis.

Effect of different dialyzer membranes on serum angiotensin-converting enzyme during hemodialysis.

The effects of different dialyzer membranes on serum concentration of angiotension-converting enzyme (ACE) and white blood cells during hemodialysis were examined on a cross-over basis in 20 chronically uremic patients. Hemodialysis with cuprophane membranes was associated with a significant (p less than 0.001) fall in the mean leukocyte count during the 1st hour of treatment. The use of polymethylmethacrylate membranes resulted in a more attenuated form of leukopenia and with polyacrylonitrile membranes no change was observed during hemodialysis. Hemodialysis with each membrane caused a comparable, significant (p less than 0.005) increase in serum ACE, independent of the degree of leukopenia but significantly (p less than 0.001) correlated with the increases in serum proteins. We conclude that this increase in serum ACE concentration after hemodialysis does not reflect acute damage of the pulmonary vascular endothelium during treatment and most probably is a result of hemoconcentration. Therefore, serum ACE analysis is not an indicator of dialyzer membrane biocompatibility.

Red blood cell volume distribution width (RDW) in uraemic patients on chronic haemodialysis.

Red blood cell volume distribution width (RDW) was obtained with the Coulter counter in 60 haemodialysis patients and 55 normal individuals. RDW tended to be higher in the former and the degree of increase was to some extent correlated with the underlying nephropathy. Although RDW failed to correlate with conventional tests of iron status, it was observed that iron administration could produce a decrease toward normal in RDW and a parallel increase in haemoglobin when the initial RDW was increased. In contrast, the response to iron was negligible in the patients with normal RDW basally. It was concluded that high RDW is an acceptable indicator of iron deficiency in haemodialysis patients.

Hemodialysis-associated platelet loss: study of the relative contribution of dialyzer membrane composition and geometry.

To evaluate the relative contribution that dialyzer membrane composition and geometry make to hemodialysis-associated platelet loss, the effect of a single dialysis with three different types of dialyzers on platelet count was examined on a cross-over basis in 19 uremic patients on maintenance hemodialysis. Also, the plasma levels of antithrombin-iii before and after dialysis were measured, but no significant variations were found regardless of which dialyzer was in use. Our patients suffered significant platelet loss during cuprophan dialysis, but not polyacrylonitrile dialysis. More than 99% of initial circulating platelets were recovered at the end of polyacrylonitrile dialysis, whereas cuprophan dialysis did leave a significantly lower percentage of circulating platelets (p less than 0.05). The internal comparison of results obtained with the two cuprophan dialyzers used shows no difference as to the dialyzer geometry (flat plate or hollow fiber). This indicates that the membrane composition is the major factor influencing hemodialysis-associated platelet loss. We suggest that patients with low platelet count and/or with risk of bleeding may benefit from polyacrylonitrile dialysis.

Immune response to a recombinant hepatitis B vaccine in hemodialysis patients.

A 20-microgram dose of a recombinant hepatitis B vaccine was given at 0, 1, 2 and 6 months to 24 hemodialysis patients. From month 7 (i.e., 1 month after the fourth injection), 58.3% (14/24) of the patients had developed protective levels of antibodies against hepatitis B surface antigen (anti-HBs). In patients responding to vaccination, the fourth injection led to an abrupt rise of the anti-HBs titres which reached their maximum 2 months later, that is, in month 8. At that time, the geometric mean titre of anti-HBs was 145.79 mlU/ml. Eighteen months after the start of vaccination, 50% (12/24) of the patients were maintaining protective levels of anti-HBs antibodies. It is noteworthy that these results could be obtained with a considerably lower dosage than previously recommended.

[Osteo-articular amyloidosis caused by dialysis. Clinical and radiologic aspects]. / Amiloidosi osteoarticolare da dialisi. Aspetti clinici e radiologici.

Twenty-nine patients who had received chronic hemodialysis for more than 5 years provided the material for the present study. In 12 of them (41%) there were radiological findings of dialysis related amyloidosis, mainly destructive spondyloarthropathy of the cervical spine (n = 11) and geodes of the shoulder (n = 5). When compared with negative patients, these patients were significantly older (p less than 0.001 and had been dialyzed for longer periods of time (p less than 0.01). Moreover, in such patients there was an higher incidence of carpal tunnel syndrome (p less than 0.025) and shoulder pain (p less than 0.001). Our results confirm that osteoarticular amyloidosis is a frequent long-term complication of chronic hemodialysis and underline the correlation between clinical and radiological findings.

[Significance of serum levels of beta-2-microglobulin in dialysis patients]. / Significato dei livelli sierici di beta-2-microglobulina nei pazienti in dialisi.

beta 2M has been shown to be a major constituent of the amyloid deposits developing in uremic patients undergoing long-term hemodialysis. In this study, serum levels of beta 2M were determined in 67 hemodialysis patients and a mean +/- SD concentration of 57.8 +/- 18.5 mg/L was obtained. There was no difference in the concentration of the substance between the patients with evidence of dialysis-related amyloidosis and those without it. Moreover, no correlation between beta 2M levels and duration of hemodialysis was found. Interestingly, the patients with residual diuresis had a significantly lower mean beta 2M concentration than the anuric patients (35.0 +/- 13.1 vs 62.8 +/- 15.8 mg/L, p less than 0.001). Not surprisingly, a significant decrease in the predialysis serum concentration of the substance was obtained after changing treatment from cuprophan hemodialysis to hemodialysis with high-permeable membranes (delta beta 2M = -16.1 +/- 14.4 mg/L at month 6, p less than 0.01). These results suggest the possible long-term use of these membranes to reduce risk of dialysis-related amyloidosis.

Successful declotting of arteriovenous grafts with local infusion of urokinase in hemodialyzed patients.

Local infusion of urokinase was used in 15 cases of thrombotic occlusion of polytetrafluoroethylene grafts in 10 hemodialyzed patients. The treatment was successful in all patients except one in whom recurring thrombosis occurred because of junctional stenosis at the venous anastomosis. No relevant side effects were observed. Follow-up data show that such treatment can significantly prolong the survival of arteriovenous grafts in hemodialyzed patients with otherwise difficult access to the circulation.

Therapeutic response of idiopathic edema to captopril.

Idiopathic edema is a condition characterized by diurnal weight gain and intermittent swelling, affecting adult females without evidence of any other condition known to cause sodium retention. It has been suggested that an alteration in the aldosterone response to upright posture plays a pathogenetic role in orthostatic sodium and water retention peculiar to this syndrome. To test this hypothesis, the effect of captopril was evaluated in 4 women with idiopathic edema. The therapeutic response was impressive in all. In summary, we noted a remarkable decrease in morning to evening weight difference, an increase in both diuresis and natriuresis, and a definite symptomatic improvement. It is therefore possible to speculate that captopril, by reversing the basic abnormality acting in idiopathic edema, may prove of benefit in most patients with this peculiar syndrome.

[High levels of carcinoembryonic antigen (CEA) in the serum of uremic patients under hemodialysis treatment]. / Livelli elevati di antigene carcinoembrionico (CEA) nel siero di pazienti uremici in trattamento emodialitico.

The serum concentration of CEA was measured twice, at intervals of 3 months, in 40 uremic patients on maintenance hemodialysis. None of them had evidence of malignancy or of any other non-malignant condition known to affect serum CEA. 111 normal adults acted as controls. The mean serum concentration of the substance was significantly higher in hemodialyzed patients (5.32 +/- 3.68 ng/ml) than in controls (1.98 +/- 1.1 ng/ml) (P less than 0.001). Levels above normal were present in 40% and in 4.5% of the cases respectively (P less than 0.0005). Comparable results were obtained at the second examination. No correlations with sex, age, underlying nephropathy, time on dialysis, or cigarette smoking were found. It is concluded that the measurement of CEA cannot be recommended as a reliable test in the screening of cancer among uremic patients on maintenance hemodialysis.

Lack of relation between secondary hyperparathyroidism and red blood cell osmotic fragility in chronic renal failure.

The possible relationship between red blood cell (RBC) osmotic fragility and secondary hyperparathyroidism (HPT) in chronic renal failure was examined in 23 uremic patients on conservative therapy and in 42 patients on maintenance hemodialysis. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (X-ray films of the hand skeleton). This study showed increased RBC osmotic fragility in uremic patients when compared with controls, with no difference between those on conservative therapy and those on maintenance hemodialysis. No correlation between RBC osmotic fragility and the hematochemical changes associated with secondary HPT was found. No difference in RBC osmotic fragility was observed with regard to the activity (alkaline phosphatase) and the severity (X-ray findings) of secondary HPT. Effective treatment of secondary HPT by either pharmacological means (1,25-dihydroxycholecalciferol) or surgical removal was not associated with consequent improvement in RBC osmotic fragility. It is concluded that secondary HPT is probably not a major factor influencing RBC osmotic fragility in chronic renal failure.

[Hbeag/Anti-hbe system and other markers for hepatitis b in a dialysis unit (author's transl)]. / Sistema HBeAg/anti-HBe ed altri markers: situazione in un centro di emodialisi.

The Authors study with radioimmunoassay for detection of HBeAg, anti-HBc, anti-HBs, anti-HBe, 22 patients on regular dialysis treatment, 41 their familiars, 10 staff dialysis unit members and 16 their familiars. There was found sure correlation between in the mean type presence of HBsAG and HBeAg and risk of infectious hepatitis B. The presence of the "e" antibody has not always protective significance and was stressed the importance of non parenteral virus transmission.