Increase in mast cells and hyaluronic acid correlates to radiation-induced damage and loss of serous acinar cells in salivary glands: the parotid and submandibular glands differ in radiation sensitivity.

The detailed mechanisms which can explain the inherent radiosensitivity of salivary glands remain to be elucidated. Although DNA is the most plausible critical target for the lethal effects of irradiation, interactions with other constituents, such as cell membrane and neuropeptides, have been suggested to cause important physiological changes. Moreover, mast cells seem to be closely linked to radiation-induced pneumonitis. Therefore, in the present study the effects of fractionated irradiation on salivary glands have been assessed with special regard to the appearance of mast cells and its correlation with damage to gland parenchyma. Sprague-Dawley strain rats were unilaterally irradiated to the head and neck with the salivary glands within the radiation field. The irradiation was delivered once daily for 5 days to a total dose of 20, 35 and 45 Gy. The contralateral parotid and submandibular glands served as intra-animal controls and parallel analysis of glands was performed 2, 4, 10 or 180 days following the last radiation treatment. Morphological analysis revealed no obvious changes up to 10 days after the irradiation. At 180 days a radiation dose-dependent loss of gland parenchyma was seen, especially with regard to serious acinar cells in parotid gland and acinar cells and serous CGT (convoluted granular tubule) cells in the submandibular gland. These changes displayed a close correlation with a concomitant dose-dependent enhanced density of mast cells and staining for hyaluronic acid. This cell population seems to conform with the features of the connective tissue mast cell type. The parotid seems to be more sensitive to irradiation than the submandibular gland. Thus, the present results further strengthen the role of and the potential interaction of mast cells with radiation-induced tissue injury and alterations in normal tissue integrity

Early rise in brain damage markers and high ICOS expression in CD4+ and CD8+ T cells during checkpoint inhibitor-induced encephalomyelitis

We report a case of rapid eradication of melanoma brain metastases and simultaneous near-fatal encephalomyelitis following double immune checkpoint blockade. Brain damage marker S-100B and C reactive protein increased before symptoms or signs of encephalomyelitis and peaked when the patient fell into a coma. At that point, additional brain damage markers and peripheral T cell phenotype was analyzed. The analyses were repeated four times during the patient’s recovery. Axonal damage marker neurofilament light polypeptide (NFL) and astrocytic damage marker glial fibrillar acidic protein (GFAP) were very high in blood and cerebrospinal fluid and gradually normalized after immunosuppression and intensive care. The costimulatory receptor inducible T cell costimulatory receptor (ICOS) was expressed on a high proportion of CD4+ and CD8+T cells as encephalomyelitis symptoms peaked and then gradually decreased in parallel with clinical improvement. Both single and double immune checkpoint inhibitor-treated melanoma patients with other serious immune-related adverse events (irAE) (n=9) also expressed ICOS on a significantly higher proportion of CD4+ and CD8+T cells compared with controls without irAE (n=12). In conclusion, our results suggest a potential role for ICOS on CD4+ and CD8+T cells in mediating encephalomyelitis and other serious irAE. In addition, brain damage markers in blood could facilitate early diagnosis of encephalitis

Feedback resonance frequency as an shm indicator (The Larsen effect)

The most efficient way of building up energy in an oscillating system is to do it in phase with a resonant frequency of the system. If the resonant frequency changes for any reason this is difficult to obtain with a static frequency generator. It is of course possible to sweep over a frequency interval to find the maximum repeatedly, but a frequency sweep takes time and it is performed at discrete frequencies. A better approach is to set the device under test in feedback resonance. This will guarantee that the frequency is always a peak in the spectrum and the adaptation to change is immediate and continuous in every aspect. A continuous observation of feedback frequency can conceivably serve as an SHM indicator. Experiments with geophones as actuators are performed. A 9-day test revealed smooth frequency variations in the 236.901 to 237.353 Hz interval. These smooth variations are believed to be caused by thermal and humidity changes in the laboratory. An audible tension release in the test device during this period was clearly indicated by a momentary step in the resonant frequency. A second experiment revealed that as the feedback gain was adjusted in steps, the feedback frequency followed suit. This establishes indirectly the relation between deformation and resonant frequency. It is thus possible to determine non-linearity with the controlled feedback resonance method

Spatial variation in Arctic hare (Lepus arcticus) populations around the Hall Basin

Inmueble de tres pisos, con tipología de planta en L y cubierta en teja de barro. En el primer piso, las puertas y ventanas cambiaron de madera a metal; en el segundo, cambió las ventanas en madera por carpintería metálica; y en el tercer piso, conserva las ventanas en madera. En 1990, estaba destinado a uso habitacional. En 2015, presentaba un regular estado de conservación y mantenía el mismo uso

Spatial variation in Arctic hare (Lepus arcticus) populations around the Hall Basin

Arctic environments have relatively simple ecosystems. Yet, we still lack knowledge of the spatio-temporal dynamics of many Arctic organisms and how they are affected by local and regional processes. The Arctic hare (Lepus arcticus) is a large lagomorph endemic to high Arctic environments in Canada and Greenland. Current knowledge about this herbivore is scarce and the temporal and spatial dynamics of their populations are poorly understood. Here, we present observations on Arctic hares in two sites on north Greenland (Hall and Washington lands) and one adjacent site on Ellesmere Island (Judge Daly Promontory). We recorded a large range of group sizes from 1 to 135 individuals, as well as a substantial variation in hare densities among the three sites (Hall land: 0 animals/100 km2, Washington land 14.5–186.7 animals/100 km2, Judge Daly Promontory 0.18–2.95 animals/100 km2). However, pellet counts suggested that both Hall land and Judge Daly Promontory hosted larger populations at other times. We suggest that our results could have been caused by three spatially differentiated populations with asynchronous population fluctuations. With food limitation being a likely driver behind the observed variation, we argue that food limitation likely interacts with predation and competition in shaping the spatial dynamics of Arctic hares in this region.The Swedish Polar Research Secretariat and National Science Foundation as part of the research program SWEDARCTIC 2016 to the project ‘Arctic Islands’ (2013-7812-106995-50). Further financial support was received from the Spanish Ministry of Economy and Competitiveness, the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chair Program, the Canadian Foundation for Innovation, Northern and Arboriginal Affairs, Centre d’Études Nordiques, and the Swedish Research Council.http://link.springer.com/journal/3002018-10-05hj2018Mammal Research InstituteZoology and Entomolog