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Biomedical subjects

F Devik

Publications and source records attributed to F Devik.

At least 19 recordsLinked to original sources
PubMed1983

Late changes following single dose roentgen irradiation of rat small intestine.

In female Wistar rats a 10 cm long exteriorized mid small intestinal segment was roentgen irradiated with 17, 19, 21 and 23 Gy as single exposures. Animals were killed in groups of 3 at intervals of 6 weeks from 2 to 50 weeks following irradiation. Irradiation injury was assessed using 8 macroscopic and histopathologic parameters, and an injury score for each animal was calculated. The parameters used were divided in 2 subgroups, early and late alterations, showing different types of development. The score for the early alterations decreased from 2 to 20 weeks following irradiation and then remained constant. The late alterations increased and seemed to stabilize about 8 weeks following irradiation. After the initial 20 weeks there was no progression of irradiation injury.

Animals↗
PubMed1983

Effects of dose fractionation on late roentgen radiation damage of rat small intestine.

In female Wistar rats a 10 cm long exteriorized mid small intestinal segment was roentgen irradiated. Nominal standard radiation doses were 17 and 19 Gy, given as a single exposure and in 2 and 3 fractions with intervals of 48 hours. Animals were killed and examined in groups of 3 every 6 weeks from 8 to 44 weeks following irradiation. Macroscopic and histopathologic parameters of irradiation injury were used to calculate an injury score for each animal. In the 2 fractions group both mortality and irradiation injury score were higher than in the single exposure and 3 fractions groups. The difference was due in particular to persisting mucosal ulcerations and epithelial atypia. Adenocarcinoma of the irradiated intestine was found in 4 animals.

Adenocarcinoma↗
PubMed1978

Growth regulation in X-irradiated mouse skin; the possible role of chalones.

Extracts of hairless mouse skin were tested for their content of epidermal G1 inhibitor and G2 inhibitor at daily intervals after X-irradiation with 4 500 or 2 250 rad. After either dose the skin extracts lacked G1 inhibitory activity on days 5 and 6 respectively after irradiation. This coincided with the time when the epidermal mitotic rate again became normal and started a period of over-shoot. The time interval of 5-6 days corresponds to the turnover time of the differentiating cells in hairless mouse back epidermis. The findings indicate that the proliferating cells in epidermis can respond to changes in local chalone concentration, even after X-irradiation at the tested doses, and that the irradiated epidermal cell population still retains some important properties inherent in a cybernetically regulated system. The local G2-inhibitory activity also varied after irradiation, but these variations could not be directly related to the corresponding mitotic rates.

Animals↗
PubMed1977

Cell migration following irradiation of the skin in mice. Effect of shielding minute areas.

In hairless mice, dorsal skin flaps were exposed to 15 kV roentgen radiation. Thin metal wires were stretched across the field. At eight different intervals, up to 6 days, and following Colcemid injection, the number and location of mitoses in the epidermis were recorded. The regeneration observed in the irradiated parts of the epidermis seems to be due to migration of cells from shielded areas, the rate during the first 6 days being about 1/6 mm per day. Migration takes place along the basal membrane of the epidermis before any increased loss of cells in superficial layers has occurred.

Animals↗