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Biomedical subjects

A Wambersie

Publications and source records attributed to A Wambersie.

At least 145 records · Page 8Linked to original sources
PubMed1980

Effect of combined misonidazole and d(50)-Be neutrons on a human melanoma transplanted into nude mice.

This paper reports the effect of two different doses (0.1 and 1 mg/g) of misonidazole on the radiosensitivity of human Na 11 melanoma transplanted into athymic nude mice. The mice were irradiated with 50 MeV neutrons. The end point was the in vitro colony-forming assay. Repair of potentially lethal damage following neutron irradiation was comparable to that observed after gamma irradiation. This repair was no longer detectable when 1 mg/g of misonidazole was used. When the 1 mg/g dose was used, the observed enhancement ratios after neutron irradiation were 1.52 for immediate plating and 1.87 for delayed plating. No toxic effect of the drug itself could be detected.

Animals↗
PubMed1979

Time factors in total body irradiation.

The role of time dose factors in the irradiation effect of the bone marrow has been investigated in mice by assessing the lethal dose 50% as a function of fraction number and dose rate. It is compared to the time dose effect in intestinal mucosa and lung, considered as critical tissues, for discussing the differential effect between these tissues.

Animals↗
PubMed1979

RBE of d(50)-Be neutrons for induction of chromosome aberrations in Allium cepa onion roots.

RBE/absorbed dose relationship of d(50)-Be neutrons was determined for the induction of chromosome aberrations in Allium cepa onion roots. Neutrons are produced at the cyclotron "Cyclone" by bombarding a thick beryllium target with 50 MeV deuterons. Two biological criteria were selected: (1) mean number of aberrations (mainly breaks) per cell in anaphase and telophase, (2) fraction of intact cells in anaphase and telophase. For the two criteria, RBE increases continuously from about 7 to 12 as the neutron absorbed dose decreases from 0.4 to 0.1 Gy. RBE values for the first criterion are slightly higher than for the second one. This observation is interpreted in terms of the analysis of the distribution of the aberrations in the cells. In logarithmic coordinates, RBE/absorbed dose relationships for the two criteria are almost linear with a slope close to -1/2. RBE values observed for induction of chromosome aberrations in Allium cepa are higher than those generally observed for biological effects related to mammalian cell lethality.

Beryllium↗
PubMed1978

[Intestinal tolerance in mice after low dose rate 60CO irradiation. Implications for radiotherapy].

Influence of absorbed dose rate has been studied in BALB/c mice for early intestinal tolerance. After selective abdominal irradiation, LD50 at 5.5 days increases from 12.36 to 20.22 and 21.79 Gy when dose rate decreases from 0.61 to 0.054 and 0.026 Gy/mn. LD50 at 6.5 days increases from 12.05 to 19.22 and 21.58 Gy respectively. The LD50 ratios are then 1.6 and 1.8 for both endpoints. After total body irradiation. LD50 at 5.5 days increases from 9.92 to 15.20and 16.83 Gy when dose rate decreases from 0.56 to 0.049 and 0.024 Gy/mn. The corresponding LD50 ratios, i.e. 1.5 and 1.7, are then similar to the former ones. Increase of LD50 when decreasing dose rate is in agreement with that expected taking into account only repair of sublethal lesions, for the generally accepted cellular models.

Animals↗
PubMed1978

[RBE/absorbed dose relationship of d(50)-Be neutrons determine for early intestinal tolerance in mice].

RBE/absorbed dose realtionship of d(50)-Be neutrons (ref.: 60Co) was determined using intestinal tolerance in mice (LD50) after single and fractionated irradiation. RBE is 1.8 for a single fraction (about 1000 rad 60Co dose); it increases when decreasing dose and reaches the plateau value of 2.8 for a 60Co dose of about 200 rad. This RBE value is used for the clinical applications with the cyclotron "Cyclone" at Louvain-la-Neuve.

Animals↗