Marzia Cerpelloni

Blood toluene as a biological index of environmental toluene exposure in the "normal" population and in occupationally exposed workers immediately after exposure and 16 hours later

Blood toluene was measured in a group of 100 workers occupationally exposed to a mean 8-h environmental toluene concentration of 128 μg/l (34 ppm), and in a group of 269 “normal” subjects without occupational exposure to toluene. The mean blood toluene of the workers at the end of the shift and the following morning, after 16 h, was 457 and 38 μg/l, respectively. The normal subjects had a blood toluene level of 1.1 μg/l. On the basis of the highly significant correlation between blood toluene and occupational exposure, it can be calculated that environmental toluene exposure of 188 and 377 μg/l (50 and 100 ppm) gives end-of-shift blood toluene levels of 690 and 1390 μg/l, respectively. The corresponding blood toluene levels on the following morning are 50 and 100 μ/l, respectively.

Nitrous oxide in blood and urine of operating theatre personnel and the general population

Nitrous oxide (N2O) was assayed in 676 urine samples and 101 blood samples provided after exposure by operating theatre personnel from nine hospitals. The blood and urine assays were repeated in 25 subjects 18 h after the end of exposure. For 80 subjects, environmental N2O was also measured during intraoperative exposure. Mean urinary N2O in the 676 subjects at the end of exposure was 40 μg/l (range 1–3805 μg/l); in 10 of the 676 subjects, urinary N2O was in the range 279–3805 μg/l (mean 1202 μ/l). The 98th percentile was 120 μg/l. Mean blood N2O at the end of exposure, measured in 101 subjects, was 21 μg/l (median 16 μg/l, range 1–75 μg/l). Blood and urine N2O (1.5 μg/l and 4.9 μg/l, respectively) in 25 subjects, 18 h after exposure, was significantly higher than in occupationally non-exposed subjects (blood 0.91 μg/l, urine 1 μg/l). Environmental exposure was significantly related to blood and urinary N2O (r = 0.59 andr = 0.64, respectively). Blood and urinary N2O were significantly related to each other (r = 0.71), and were equivalent to about 25% of the environmental exposure level. The mean urinary N2O of 1202 μg/l in 10/676 subjects was not related to environmental exposure in the operating theatre. The highest urinary N2O levels measured in these 10/676 subjects could be explained by an asymptomatic urinary infection.

Lanthanide-doped CaF2 and SrF2 nanoparticles for biomedical applications: in vivo and in vitro experimental studies

Among the wide range of nanoparticles (NPs) studied for diagnostic and therapeutic applications lanthanide-doped nanosystems have raised special interest [1]. Their very small dimension (10 nm) and upconversion emission property have increased the range of their applications from contrast agent probes in bioimaging to drug delivery systems [2,3]. Here, the cytotoxicity of rare earth (Yb and Er)-doped CaF2 and SrF2 NPs has been investigated both in vitro and in vivo. In vitro studies have been conducted in a motoneuron cell line as model of neuronal interaction, and in a line of human dendritic cells which play a key role in the immune response. In the motoneuron cell line, a weak response was observed at early time points while the cell viability showed an increment, except for the highest concentration of lanthanide- doped NPs. The levels of cytokines released from human dendritic cells were low and dose-dependent. The NP biodistribution was investigated after a single peripheral administration in mice. Aggregates of NPs were shown, with different techniques, mostly in peripheral organs (spleen and liver) after one day. A limited penetration of both CaF2 and SrF2 NPs was seen in the brain parenchyma, associated with a mild astrocytic activation. Since the present in vitro findings indicate that lanthanide- doped NPs are safe, and the in vivo data show that they can enter the brain parenchyma crossing the blood-brain barrier, these NPs may represent promising tools for diagnostic and therapeutical applications.