The threshold length for fiber-induced acute pleural inflammation: shedding light on the early events in asbestos-induced mesothelioma

Suspicion has been raised that high aspect ratio nanoparticles or nanofibers might possess asbestos-like pathogenicity. The pleural space is a specific target for disease in individuals exposed to asbestos and by implication of nanofibers. Pleural effects of fibers depends on fiber length, but the key threshold length beyond which adverse effects occur has never been identified till now because all asbestos and vitreous fiber samples are heterogeneously distributed in their length. Nanotechnology advantageously allows for highly defined length distribution of synthetically engineered fibers that enable for in-depth investigation of this threshold length. We utilized the ability to prepare silver nanofibers of five defined length classes to demonstrate a threshold fiber length for acute pleural inflammation. Nickel nanofibers and carbon nanotubes were then used to strengthen the relationship between fiber length and pleural inflammation. A method of intrapleural injection of nanofibers in female C57Bl/6 strain mice was used to deliver the fiber dose, and we then assessed the acute pleural inflammatory response. Chest wall sections were examined by light and scanning electron microscopy to identify areas of lesion; furthermore, cell-nanowires interaction on the mesothelial surface of the parietal pleura in vivo was investigated. Our results showed a clear threshold effect, demonstrating that fibers beyond 4 μm in length are pathogenic to the pleura. The identification of the threshold length for nanofiber-induced pathogenicity in the pleura has important implications for understanding the structure-toxicity relationship for asbestos-induced mesothelioma and consequent risk assessment with the aim to contribute to the engineering of synthetic nanofibers by the adoption of a benign-by-design approach.     

Reexamination of magnetic isotope and field effects on adenosine triphosphate production by creatine kinase

The influence of isotopically enriched magnesium on the creatine kinase catalyzed phosphorylation of adenosine diphosphate is examined in two independent series of experiments where adenosine triphosphate (ATP) concentrations were determined by a luciferase-linked luminescence end-point assay or a real-time spectrophotometric assay. No increase was observed between the rates of ATP production with natural Mg, (24)Mg, and (25)Mg, nor was any significant magnetic field effect observed in magnetic fields from 3 to 1,000 mT. Our results are in conflict with those reported by Buchachenko et al. [J Am Chem Soc 130:12868-12869 (2008)], and they challenge these authors' general claims that a large (two- to threefold) magnetic isotope effect is "universally observable" for ATP-producing enzymes [Her Russ Acad Sci 80:22-28 (2010)] and that "enzymatic phosphorylation is an ion-radical, electron-spin-selective process" [Proc Natl Acad Sci USA 101:10793-10796 (2005)].     

Length-dependent retention of carbon nanotubes in the pleural space of mice initiates sustained inflammation and progressive fibrosis on the parietal pleura

The fibrous shape of carbon nanotubes (CNTs) raises concern that they may pose an asbestos-like inhalation hazard, leading to the development of diseases, especially mesothelioma. Direct instillation of long and short CNTs into the pleural cavity, the site of mesothelioma development, produced asbestos-like length-dependent responses. The response to long CNTs and long asbestos was characterized by acute inflammation, leading to progressive fibrosis on the parietal pleura, where stomata of strictly defined size limit the egress of long, but not short, fibers. This was confirmed by demonstrating clearance of short, but not long, CNT and nickel nanowires and by visualizing the migration of short CNTs from the pleural space by single-photon emission computed tomographic imaging. Our data confirm the hypothesis that, although a proportion of all deposited particles passes through the pleura, the pathogenicity of long CNTs and other fibers arises as a result of length-dependent retention at the stomata on the parietal pleura.     

Uncommon Foreign Body Reactions Occurring in the Lip: Clinical Misdiagnosis and the Use of Special Techniques of Analysis

This study reports three interesting cases of nodular submucosal lip lesions where foreign-body reactions of unknown origin were detected on hematoxylin and eosin (H&E) analysis. These materials were evaluated under polarized light microscopy, scanning electron microscopy and by energy dispersive X-ray analysis. The results revealed the following materials: an interdental toothbrush bristle, silica, and iron. Unusual mucosal foreign body reaction cases have been reported, but few publications used special techniques to identify the specific foreign material. Clinicians and pathologists might consider these techniques for identifying the precise origin of these foreign bodies.     

Clinicopathological features and immunohistochemical expression of p53, Ki‐67, Mcm‐2 and Mcm‐5 in proliferative verrucous leukoplakia

J Oral Pathol Med (2010) 39 : 447–452 Background: Proliferative verrucous leukoplakia (PVL) is a distinct and aggressive type of oral leukoplakia which affects elderly women without risk behavior and presents high rates of malignant transformation. The objective of the present study was to evaluate the clinicopathological characteristics and the distribution of cell proliferation markers, aiming to elucidate the distinct biological behavior of the PVL. Methods: Clinical and microscopical features of 12 patients with PVL were reviewed. Immunohistochemical analysis for p53, Ki‐67, Mcm‐2 and Mcm‐5 were performed and the data were correlated. Results: All patients were women, above 50 years of age, 91.7% were non‐smoker and 100% were non‐habitual drinker. Alveolar ridge (66.6%), tongue (50%) and buccal mucosa (41.6%) were the most affected sites. Four patients developed squamous cell carcinoma (SCC). The immunohistochemical findings showed higher positivity for p53, Ki‐67, Mcm‐2 and Mcm‐5 in SCCs. However, some patients with mild or moderate dysplasia, specially the patients who developed SCC, presented high expression of Mcm‐2 and Mcm‐5. Conclusions: High immunoexpression of Mcm‐2 and Mcm‐5 in mild and moderate dysplasia could be helpful to predict the malignant transformation of PVL.     

Phenotypic characterization of regulatory T cells populations in maternal blood,cord blood and placenta from diabetic mothers

Purpose: Changes in regulatory T cells (Treg) in peripheral blood are associated with a number of pathologies, including diabetes. However, the immunological responses of pregnant diabetic women remain scarcely known, and the effects of Treg cells in these patients have yet to be investigated. The present study characterized the expression of regulatory T cells in the maternal blood, cord blood and placenta of diabetic pregnant women.

Materials and methods: The women were divided according to glycemic status into a non-diabetic (ND; N?=?20) or type 2 diabetic (T2DM; N?=?20) group. Cell subsets were determined by flow cytometry.

Results: Compared to ND, T2DM blood cells exhibited a higher expression of CD25⁺, Foxp3⁺, CD4⁺CD25⁺, CD4⁺Foxp3⁺ and CD25⁺Foxp3⁺; and cord blood cells showed a lower expression of CD25⁺, CD4⁺Foxp3⁺ and CD25⁺Foxp3⁺. In the placenta of T2DM, the villous layer of the proportion, CD3⁺ and CD25 was lower than that of CD4⁺Foxp3⁺ and CD25⁺Foxp3⁺, and the extravillous placenta layer contained the lowest levels of CD4⁺ and CD25⁺ and highest proportions of CD4⁺Foxp3⁺. In maternal blood from T2DM, the frequency of CD3⁺CD95⁺ and CD3CD4⁺ T cells expressing CD95⁺ was lower. In cord blood from T2DM, the rate of CD3⁺CD95⁺ was lower. The placenta villous layer of T2DM showed a lower count of CD3⁺CD95⁺ and of CD3CD4⁺ T cells expressing CD95⁺, whereas the number of cells expressing CD3⁺CD45RO⁺ decreased in both placental layers.

Conclusion: The data obtained suggest that hyperglycemia changes the phenotypes of regulatory T cells and Fas expression in memory T cells.