Occupational Asthma: New Low-Molecular-Weight Causal Agents, 2000–2010

Background. More than 400 agents have been documented as causing occupational asthma (OA). The list of low-molecular-weight (LMW) agents that have been identified as potential causes of OA is constantly expanding, emphasizing the need to continually update our knowledge by reviewing the literature. Objective. The objective of this paper was to identify all new LMW agents causing occupational asthma reported during the period 2000–2010. Methods. A Medline search was performed using the keywords occupational asthma, new allergens, new causes, and low-molecular-weight agents. Results. We found 39 publications describing 41 new LMW causal agents, which belonged to the following categories: drugs (n = 12), wood dust (n = 11), chemicals (n = 8), metals (n = 4), biocides (n = 3), and miscellaneous (n = 3). The diagnosis of OA was confirmed through SIC for 35 of 41 agents, peak expiratory flow monitoring for three (3) agents, and the clinical history alone for three (3) agents. Immunological tests provided evidence supporting an IgE-mediated mechanism for eight (8) (20%) of the newly described agents. Conclusion. This paper highlights the importance of being alert to the occurrence of new LMW sensitizers, which can elicit OA. The immunological mechanism is explained by a type I hypersensitivity reaction in 20% of all newly described LMW agents

Tachyonic perturbations in AdS5_5 orbifolds

We show that scalar as well as vector and tensor metric perturbations in the Randall-Sundrum II braneworld allow normalizable tachyonic modes, i.e., possible instabilities. These instabilities require nonvanishing initial anisotropic stresses on the brane. We show with a specific example that within the Randall-Sundrum II model, even though the tachyonic modes are excited, no instability develops. We argue, however, that in the cosmological context instabilities might in principle be present. We conjecture that the tachyonic modes are due to the singularity of the orbifold construction. We illustrate this with a simple but explicit toy model.Comment: 11 pages, matches published versio

New methodology for specific inhalation challenges with occupational agents

<p>Abstract</p> <p>Background</p> <p>Inhalation challenges are used for diagnosing occupational asthma (OA). The initial methodology consisted of a "realistic" exposure without monitoring nor controlling exposure. Our aim was to design an equipment, called the GenaSIC, that allows the generation of various agents regardless of the formulation and to assess the feasibility of its use in patients investigated for OA.</p> <p>Results</p> <p>GenaSIC can generate lactose, flour, malt, isocyanates, formaldehyde and N-butyl acetate with precise and fairly stable concentrations. Using N-butyl-acetate as a control agent and real time measurement, we show that normal breathing has a negligible effect on the concentration. We exposed forty-four different subjects to a control agent and/or to a suspected occupational agent. Nineteen of the subjects were only exposed to N-butyl acetate as a control agent without experiencing any significant irritant effect (no significant changes in spirometry thereafter). Eight subjects who were exposed to both N-butyl acetate and formaldehyde did not show significant reactions. Seven subjects were exposed to dry particles (flour in six instances, malt in the other) and five showed immediate asthmatic reactions which changes in FEV1 from 20% to a maximum of 28%. Finally, ten subjects were exposed to isocyanates, four of whom showed a positive reaction, including one subject with immediate maximum changes in FEV1 of 22%.</p> <p>Conclusion</p> <p>GenaSIC offers the possibility of reliable and safe exposures to dry particles, formaldehyde and isocyanates in the investigation of OA.</p

Suspicious liver nodule in chronic liver disease: Usefulness of a second biopsy

PURPOSE: To assess the usefulness of a second biopsy when the first one was inconclusive in patients with a liver nodule found during the follow-up for chronic liver disease. MATERIALS AND METHODS: Among 381 patients (544 nodules) included in a prospective study designed to evaluate the accuracy of imaging for the diagnosis of small hepatocellular carcinoma (HCC) in chronic liver disease, 254 nodules were biopsied. The following histological results were considered as conclusive: HCC, dysplastic or regenerative nodule, and other identified tumors (benign or malignant). For nodules with inconclusive results (e.g. fibrosis or no definite focal lesion), a second biopsy was suggested, but was not mandatory. RESULTS: A total of 242 patients (194 men, 48 women; mean age, 61.9±9.5 [SD]; range: 40.2-89.0years) with 254 nodules underwent a first biopsy. Mean nodule diameter was 19.2±5.4mm (range: 10-33mm). The first biopsy was conclusive in 189/254 nodules (74.4%): 157 HCCs (83.1%), 11 regenerative nodules (5.8%), 10 dysplastic nodules (5.3%), 3 cholangiocarcinomas (1.6%), and 8 other tumors (4.2%). Among the 65 nodules for which the first biopsy was inconclusive, a second biopsy was performed for 17 nodules in 16 patients within 6 months of the first one. It was conclusive in 13/17 nodules (76.5%): 10 HCCs (76.9%), 2 dysplastic nodules (15.4%), and 1 other tumor (7.7%). In 4/17 nodules (23.5%), no definitive diagnosis could be provided. CONCLUSION: The diagnostic yield of a second biopsy of a suspicious lesion suggestive of HCC in chronic liver disease is not decreased compared to the first one. Repeated biopsy after a first negative one could be an alternative option to the follow-up of patients with chronic liver disease

Drinfeld-Twisted Supersymmetry and Non-Anticommutative Superspace

We extend the analysis of hep-th/0408069 on a Lorentz invariant interpretation of noncommutative spacetime to field theories on non-anticommutative superspace with half the supersymmetries broken. By defining a Drinfeld-twisted Hopf superalgebra, it is shown that one can restore twisted supersymmetry and therefore obtain a twisted version of the chiral rings along with certain Ward-Takahashi identities. Moreover, we argue that the representation content of theories on the deformed superspace is identical to that of their undeformed cousins and comment on the consequences of our analysis concerning non-renormalization theorems.Comment: 1+17 pages; typos fixed, minor correction

Nature of singularities in anisotropic string cosmology

We study nature of singularities in anisotropic string-inspired cosmological models in the presence of a Gauss-Bonnet term. We analyze two string gravity models-- dilaton-driven and modulus-driven cases-- in the Bianchi type-I background without an axion field. In both scenarios singularities can be classified in two ways- the determinant singularity where the main determinant of the system vanishes and the ordinary singularity where at least one of the anisotropic expansion rates of the Universe diverges. In the dilaton case, either of these singularities inevitably appears during the evolution of the system. In the modulus case, nonsingular cosmological solutions exist both in asymptotic past and future with determinant $D=+\infty$ and D=2, respectively. In both scenarios nonsingular trajectories in either future or past typically meet the determinant singularity in past/future when the solutions are singular, apart from the exceptional case where the sign of the time-derivative of dilaton is negative. This implies that the determinant singularity may play a crucial role to lead to singular solutions in an anisotropic background.Comment: 21 pages, 8 figure

Quivers, words and fundamentals

40 pages + Appendices, 9 figures40 pages + Appendices, 9 figure