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ePaper created 2017-06-21, 10:00:36 | version 1.38.0
| study temperature-related damage of the DPSC Fig. 3 Fig. 3: Control cells exhibited a normal · Contrasting with 1 % Osmiumtetroxyde and 1 % appearance at 37 °C under REM. Cell potassium ferrocyanide for two hours processes, microvilli-like structures on · Rinsing with cacodylate buffer for three times as termediate temperature levels. Light microscopy examinations showed significant morphological changes at temperatures from 46.5 °C ± 0.5 °C. the cell surface (their numbers seems well as with Aqua dest. to depend on the level of cell activity) as well as the elongated cell shape are clearly visible. · Dehydration with increasing alcohol concentration: 20 %, 30 %, 50 %, 70 %, 90 %, 2 x in 100 % EtOH for 10' each · Embedding in Epon (epoxy resin), polymerisation for four days at 60 °C · Ultramicrotomy, ultra-thin sections (70 nm; Leica Ultracut S, Leica Mikrosysteme GmbH) · Dyeing of the sections with 1 % Uranyl acetate in methanol and 1 drop of acetic acid for 10' · Microscope: Zeiss EM 906 Results Light microscopy and vitality test The cells received thermal treatment at temper- atures ranging from 37 °C to 60 °C and varying in- At temperatures from 37 °C to 45 °C, all cells exhibited a green calcein fluorescence. At tem- peratures of 46 °C and above, lethal results were detected in some of the cells that had undergone thermal treatment. The number of lethal cells in- creased in correspondence to a rise in temperature. At temperatures of 46 °C to 56.5 °C, the number of lethal cells had almost doubled 24 h after ther- mal treatment in comparison to the number of le- thal cells one hour after thermal treatment (Table 1, Fig. 1). Starting at 56.5 °C, this phenomenon ceased, with about the same number of lethal cells. This temperature of 56.5 °C corresponded to the LD50 value (50 % lethality). No cell survived thermal treatment at 58 °C. Fig. 4: REM: Thermally treated DPSC showed external signs of cellular damage at 46.5 °C: The cell usually changes its elongated shape and starts to round. At 50 °C, an increased rounding can be observed. The cell seems to contract so fast that a part of the cytoplasm processes tears off (arrows). The surface structure of the cells is effected as appearance and number of microvilli change. Fig. 4 32 roots 2 2017