Overshooting the critical threshold for the Greenland ice sheet.

Melting of the Greenland ice sheet (GrIS) in response to anthropogenic global warming poses a severe threat in terms of global sea-level rise (SLR)1. Modelling and palaeoclimate evidence suggest that rapidly increasing temperatures in the Arctic can trigger positive feedback mechanisms for the GrIS, leading to self-sustained melting2-4, and the GrIS has been shown to permit several stable states5. Critical transitions are expected when the global mean temperature (GMT) crosses specific thresholds, with substantial hysteresis between the stable states6. Here we use two independent ice-sheet models to investigate the impact of different overshoot scenarios with varying peak and convergence temperatures for a broad range of warming and subsequent cooling rates. Our results show that the maximum GMT and the time span of overshooting given GMT targets are critical in determining GrIS stability. We find a threshold GMT between 1.7 °C and 2.3 °C above preindustrial levels for an abrupt ice-sheet loss. GrIS loss can be substantially mitigated, even for maximum GMTs of 6 °C or more above preindustrial levels, if the GMT is subsequently reduced to less than 1.5 °C above preindustrial levels within a few centuries. However, our results also show that even temporarily overshooting the temperature threshold, without a transition to a new ice-sheet state, still leads to a peak in SLR of up to several metres.

[Malignant mesotheliomas with unknown exposure to asbestos: a re-examination]. / Mesoteliomi maligni con esposizione ad amianto ignota: un riesame a distanza.

INTRODUCTION: Malignant Mesothelioma (MM) is a rare neoplasm associated with asbestos exposure. In 24,5% of MM cases reported to the Lombardy Mesothelioma Registry (LMR), asbestos exposure has been defined as "unknown". OBJECTIVE: To evaluate the cases with "unknown exposure to asbestos" diagnosed in 2000-2004 in agreement with new knowledge about source of asbestos exposure. METHODS: Information regarding exposure has been reviewed in order to select the cases susceptible of further investigations, including: interview of relatives and/or colleagues; further evaluations by local PSAL (Prevention and Security in workplace) services; contact of industrial hygienists; analysis of production processes. The same procedure has been followed for extra-occupational exposure. These cases have been subjected to the LMR evaluation group. RESULTS: Fourthy four out of 364 (12,1%) MM have been reclassified. In 47,7% of the cases, a "possible occupational exposure" has been recognized, 15,9% have been attributed a "certain occupational exposure", while 36,4% an extra-occupational (domestic, environmental and leisure-time) exposure. No significant differences between age, sex, cancer site, diagnostic certainty, residence, year of diagnosis, interviewed subjects were detected. The occupational sector with the highest amount of reclassifications was the clothing production. CONCLUSIONS: The detailed reconstruction of clinical and occupational history and of lifestyle habits of patients affected by MM, close cooperation with Local Services of Occupational Medicine and literature review make it possible for previously overlooked asbestos exposure to be acknowledged.

Nasal response in patients with diisocyanate asthma.

BACKGROUND: To date, no studies have assessed nasal and bronchial response to diisocyanates during specific inhalation challenges (SIC). OBJECTIVES: This study was performed to assess nasal response during SIC with diisocyanates (nasal and oral breathing) in patients with suspected occupational asthma due to these agents. METHODS: Fourteen patients with suspected clinical history of diisocyanate-induced asthma were challenged with diisocynates in a 7m3 chamber. Nasal response testing during challenges was assessed by acoustic rhinometry, peak nasal inspiratory flow (PNIF), and visual analog scale (VAS), alongside bronchial responses. RESULTS: Eleven patients had a significant asthmatic response to diisocyanates. None reported clear work-related nasal symptoms. In patients with positive bronchial response to diisocyanates, nasal mean minimal cross-sectional area (MCA) decreased by 26.9%, nasal volume at 5 cm decreased by 33.5%, and PNIF decreased by 28.3%, all from baseline. A positive nasal response was elicited in 45%, 54%, and 45% of patients, respectively. A significant increase in VAS was observed in 4 patients. Three patients with negative bronchial response had a negative nasal response. CONCLUSION: SIC revealed an objective nasal response in around 50% of patients with occupational asthma due to diisocyanates, in spite of the fact that none of them reported work-related nasal symptoms. The clinical significance of this finding is a poor association between nasal symptoms at work and an objective nasal response during positive SIC with diisocyanates.

[Occupational allergic "march". Rapid evolution of contact dermatitis to ammonium persulfate into airborne contact dermatitis with rhinitis and asthma in a hairdresser]. / La marcia dell'allergia. Rapida evoluzione di una dermatite da contatto da ammonio persolfato in airborne contact dermatitis con rinite ed asma bronchiale.

BACKGROUND: Hairdressers are exposed to irritants and allergenic compounds that may cause contact dermatitis, rhinitis and asthma. OBJECTIVES: In this paper we describe the case of a female, age 33 years, who developed contact dermatitis after 10 years of exposure to ammonium persulfate. METHODS: After 7 months of progressively extensive and persistent skin lesions, respiratory symptoms appeared that were related to the occupational exposure (on-off test). SIDAPA and specific occupational patch test for hairdressers and occupational challenge with ammonium persulfate were performed. Clinical parameters of inflammation, ECP (eosinophil cationic protein) and exhaled nitric oxide (FeNO) were detected before and after the specific bronchial challenge. RESULTS: The patch test was positive to ammonium persulfate (++), and bronchial challenge for ammonium persulfate showed a significant late response (FEV1 decrease--33%). Both FeNO and ECP showed a significant increase after 24 hours. Dermatitis, urticaria and angioedema occurred on the uncovered skin due to airborne contact. Topic steroids and anti-histaminic drugs resolved the clinical symptoms. CONCLUSIONS: Bronchial challenge is, in fact, considered to be the gold standard for the diagnosis of occupational asthma, although new inflammatory parameters can contribute to the diagnosis and can be useful for monitoring after a specific inhalation test with occupational agents. The described case summarizes the evolution from contact dermatitis to inhalation allergy, suggesting the occurrence of an allergic "march" for occupational allergy.