Human primary bronchial epithelial cells respond differently to titanium dioxide nanoparticles than the lung epithelial cell lines A549 and BEAS-2B

We have compared the cellular uptake and responses of five preparations of nanocrystalline titanium dioxide (TiO(2)) between normal human bronchial epithelial (NHBE) cells and epithelial cell lines (A549 and BEAS-2B). The P25 nanoparticles, containing both anatase and rutile modifications, induced reactive oxygen species (ROS) and secretion of the neutrophil chemoattractant IL-8 in all three cell types used. Pure anatase and rutile particles provoked differential IL-8 response in A549 and no response in BEAS-2B cells despite similar formation of ROS. The pure TiO(2) modifications also provoked release of the inflammatory mediators: IL-6, G-CSF and VEGF, in NHBE cells but not in the two cell lines. We conclude that the responsiveness of lung epithelial cells is strongly dependent on both the physicochemical properties of TiO(2) nanoparticles and the type of responder cells. The differential pro-inflammatory responsiveness of primary lung epithelial cells compared with immortalized cell lines should be considered in the assessment of adverse reactions to inhaled nanoparticles.     

Array comparative genomic hybridization of keratoacanthomas and squamous cell carcinomas: different patterns of genetic aberrations suggest two distinct entities

Keratoacanthoma (KA) is a benign keratinocytic neoplasm that spontaneously regresses after 3-6 months and shares features with squamous cell carcinomas (SCCs). Furthermore, there are reports of KAs that have metastasized, invoking the question of whether KA is a variant of SCC (Hodak et al., 1993). To date, no reported criteria are sensitive enough to discriminate reliably between KA and SCC, and consequently there is a clinical need for discriminating markers. Our previous study analyzed 132 KAs and 29 SCCs and revealed significantly different regions of genomic aberrations using chromosomal comparative genomic hybridization (CGH). In the present study, we applied array CGH to investigate 98 KAs and 22 SCCs from the above samples. The result shows that all KAs and SCCs have some degree of genetic aberrations. The distribution of numbers of aberrant clones per sample differed significantly between KAs and SCCs (P<0.02), which also demonstrated recurrent aberrations that differed significantly (P<0.001), as illustrated by unsupervised cluster analysis. Classifiers for clinicopathological parameters of KAs were established based on t-test statistics and permutation tests. Tumor size, fibrosis, and inflammation, which are related to the developmental stages of KAs, showed significant (t-test, permutation test) associations with aberrations of selected genomic regions. This suggests chromosomal instability during the whole life cycle of KAs.     

Effect of receptor binding domain mutations on receptor binding and transmissibility of avian influenza H5N1 viruses

Although H5N1 influenza viruses have been responsible for hundreds of human infections, these avian influenza viruses have not fully adapted to the human host. The lack of sustained transmission in humans may be due, in part, to their avian-like receptor preference. Here, we have introduced receptor binding domain mutations within the hemagglutinin (HA) gene of two H5N1 viruses and evaluated changes in receptor binding specificity by glycan microarray analysis. The impact of these mutations on replication efficiency was assessed in vitro and in vivo. Although certain mutations switched the receptor binding preference of the H5 HA, the rescued mutant viruses displayed reduced replication in vitro and delayed peak virus shedding in ferrets. An improvement in transmission efficiency was not observed with any of the mutants compared to the parental viruses, indicating that alternative molecular changes are required for H5N1 viruses to fully adapt to humans and to acquire pandemic capability.     

Scavenging strategy for specific activity improvement: application to a new CXCR4‐specific cyclopentapeptide positron emission tomography tracer

Huisgen cycloaddition is attractive to label peptide because of its rapidity and bioorthogonality. However, for larger tracers, the physico‐chemical differences between the precursor and the tracer are usually insufficient to allow their separation by HPLC, reducing the specific activity. This is of importance for peptidic tracers because the combination of their high‐affinity receptor with low specific activity results in the precursor saturating the receptors, causing non‐specific tracer binding. Here, we report a fast, one‐pot, general strategy to circumvent this issue, yielding a tracer of improved specific activity. It consists in adding a lipophilic azide after the labeling step to scavenge unreacted precursor into a more lipophilic species that does not co‐elute with the tracer. We applied this strategy to a new fluorinated cyclopentapeptidic CXCR4 antagonist for the PET imaging of cancer, CCIC15, for which we managed to reduce the apparent peptide concentration by a factor of 34 in 10 min. This tracer was radiolabeled by click chemistry with 2‐[¹⁸F]fluoroethylazide, yielding the tracer in 18 ± 6% (n = 5) end‐of‐synthesis radiochemical yields (EOS‐RCY) in 1.5 h from [¹⁸F]fluoride with a specific activity of 19.4 GBq µmol^?1. Preliminary biological evaluation of the probe confirmed potency and specificity for CXCR4; further biological evaluation is underway.     

Prospective study of genital human papillomaviruses and nonmelanoma skin cancer

Genital high‐risk human papillomaviruses (HPVs) cause cervical cancer and are also found in a small proportion of nonmelanoma skin cancers (NMSCs). We used cancer registry linkages to follow the 856,000 serum donors included in the Southern Sweden Microbiology Biobank or the Janus Biobank in Norway, for incident skin cancers occurring up to 30 years after serum donation. Serum samples taken before diagnosis of squamous cell carcinoma (SCC) (N = 633), basal cell carcinoma (BCC) (N = 1990) or other NMSC (N = 153) and matched samples from control donors were tested for antibodies to the genital HPV types 16 and 18. Both HPV 16 and 18 were associated with increased risk for SCC [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.1–2.6 and OR 1.7, 95% CI 1.1–2.5, respectively] and other NMSC (OR 2.3, 95% CI 1.0–5.2 and OR 3.5, 95% CI 1.4–8.7, respectively), but not for BCC. Tumor blocks from HPV16 or 18 seropositive cases were tested with real‐time polymerase chain reaction for presence of HPV16 or 18 DNA. No HPV18 DNA was found and only four of 79 SCC cases (two of which were from the perineum/perianal area), one of 221 BCC cases and zero of five cases with other NMSC contained HPV16 DNA. In conclusion, we found prospective evidence that HPV16 and 18 antibodies associate with SCC and other NMSC risk, but not with BCC risk. As only a small proportion of seropositive subjects had evidence of the corresponding HPV DNA in the tumor, most of this excess risk is likely to be due to confounders associated with genital HPV infection.     

Electrophysiological characteristics in children with listening difficulties,with or without auditory processing disorder

Abstract

Objective: To determine if the auditory middle latency responses (AMLR), auditory late latency response (ALLR) and auditory P300 were sensitive to auditory processing disorder (APD) and listening difficulties in children, and further to elucidate mechanisms regarding level of neurobiological problems in the central auditory nervous system.

Design: Three-group, repeated measure design.

Study sample: Forty-six children aged 8–14 years were divided into three groups: children with reported listening difficulties fulfilling APD diagnostic criteria, children with reported listening difficulties not fulfilling APD diagnostic criteria and normally hearing children.

Results: AMLR Na latency and P300 latency and amplitude were sensitive to listening difficulties. No other auditory evoked potential (AEP) measures were sensitive to listening difficulties, and no AEP measures were sensitive to APD only. Moderate correlations were observed between P300 latency and amplitude and the behavioural AP measures of competing words, frequency patterns, duration patterns and dichotic digits.

Conclusions: Impaired thalamo-cortical (bottom up) and neurocognitive function (top-down) may contribute to difficulties discriminating speech and non-speech sounds. Cognitive processes involved in conscious recognition, attention and discrimination of the acoustic characteristics of the stimuli could contribute to listening difficulties in general, and to APD in particular.     

Agreement of specific IgE and skin prick test in an unselected cohort of two-year-old children

The objective of this study was to evaluate the agreement between specific IgE (sIgE) and skin prick test (SPT), and the possible association between total IgE concentration and allergy-related disorders, when performed in an unselected cohort of 353 two-year olds. Median total IgE was within the reference value for two-year-old children regardless of the presence or absence of allergy-related disorders. 18.7% of the children had one or more positive reactions to SPT and/or sIgE in a panel of 12 allergens. Agreement between SPT and sIgE was variable, being best for peanut and poorest for milk. Conclusion: In young children total IgE is of limited value when evaluating allergy-related disorder. The lack of agreement among the positive tests of the sIgE and SPT for some allergens imply that these tests should not be used interchangeably, and both tests should probably be used complementarily when diagnosing atopic sensitization in small children.