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Biomedical subjects

G Mattelin

Publications and source records attributed to G Mattelin.

At least 19 recordsLinked to original sources
PubMed1995

Effect of neutrons alone or combined with diethylnitrosamine on tumor induction in the livers of infant C57BL mice.

The possible combined effects of the initiator diethylnitrosamine (DEN)+neutrons on the induction of foci, adenomas and carcinomas in the livers of C57BL/Cnb mice were evaluated. Four groups of infant mice were treated as follows: DEN alone, neutrons alone, DEN followed by neutrons and neutrons followed by DEN. Ten mice in each group were killed at 10-week intervals over 70 weeks. The following parameters were measured: body weight, liver weight, number and size of superficial macroscopic liver lesions, and number and total surface area of the different types of microscopic liver lesions. The rate of appearance of foci increased significantly at different times when a dose of 0.125 Gy of neutrons was administered 7 days before or after a dose of 1.25 micrograms of DEN. No significant differences were observed in the total surface area of foci and/or adenomas and carcinomas when increasing doses of neutrons were given 7 days before or after the administration of 1.25 and 2.5 micrograms of DEN.

Animals↗
PubMed1993

Effect of X rays alone or combined with diethylnitrosamine on tumor induction in infant mouse liver.

The possible combined effects of the initiator diethylnitrosamine (DEN) with X rays on cancer induction in C57BL/Cnb mouse liver were evaluated. Four groups of infant mice were treated as follows: with DEN alone, with X rays alone, with DEN + X rays, and with X rays + DEN. Mice in each group were killed at 10-week intervals over 70 weeks. The following parameters were measured: body weight, liver weight, number and size of macroscopic liver lesions, and number and total surface of the different types of microscopic liver lesions. The number of induced liver foci and carcinomas was found to depend essentially on the dose of DEN. X irradiation did not produce any combined effect on the induction of foci and carcinomas when given 7 days before or after DEN administration.

Animals↗
PubMed1991

Life-shortening and disease incidence in mice after exposure to gamma rays or high-energy neutrons.

Male C57Bl/Cnb and BALB/c mice were exposed to single and fractionated d(50) + Be neutrons or 137Cs gamma rays at 12 weeks of age and were followed for life-shortening and disease incidence as ascertained by autopsy and histological examinations at the time of spontaneous death. Fractionation schedules used were 10 exposures at 24-h intervals and 8 exposures at 3-h intervals for gamma rays, and 8 exposures at 3-h intervals for neutrons. The data were analyzed by the Kaplan-Meier procedure using as criteria causes of death and possible causes of death. Individual groups were compared by a modified Wilcoxon test according to Hoel and Walburg (J. Natl. Cancer Inst. 49, 361-372 (1972)). No significant difference was found in C57Bl/Cnb and BALB/c male mice between a single gamma-ray exposure and a single neutron exposure. Gamma-ray fractionation was clearly less effective in reducing survival time than a single exposure. In contrast, fractionation of neutrons was slightly, although not significantly, more effective in reducing survival time than a single exposure. The relative biological effectiveness (RBE) for life-shortening for d(50)-Be neutrons compared to gamma rays is of the order of 1 to 2 for a single exposure to neutrons and between 2 and 3 for fractionated neutrons compared to a single exposure to gamma rays. Neutron irradiation caused somewhat more cancer than gamma irradiation, and the RBE for cancer induction may be higher, probably between 2 and 3 in the range of 1 to 3 Gy, although the present data do not allow a more precise assessment.

Animals↗
PubMed1988

Life-shortening and disease incidence in C57Bl mice after single and fractionated gamma and high-energy neutron exposure.

C57Bl Cnb mice were exposed to single or fractionated d(50)+Be neutrons or 137Cs gamma-ray exposure at 12 weeks of age and were followed for life-shortening and disease incidence. The data were analyzed by the Kaplan-Meier procedure using as criteria cause of death and possible cause of death. Individual groups were compared by a modified Wilcoxon test according to Hoel and Walburg, and entire sets of different doses from one radiation schedule were evaluated by the procedure of Peto and by the Cox proportional hazard model. No significant difference was found in life-shortening of C57Bl mice between a single gamma and neutron exposure. Gamma fractionation was clearly less effective in reducing survival time than a single exposure. On the contrary, fractionation of neutrons was slightly although not significantly more effective in reducing life span than a single exposure. Life-shortening appeared to be a linear function of dose in all groups studied. The data on causes of death show that malignant tumors, particularly leukemias including thymic lymphoma, and noncancerous late degenerative changes in lung were the principal cause of life-shortening after a high single gamma exposure. Exposure delivered in 8 fractions 3 h apart was more effective in causing leukemias and all carcinomas and sarcomas than one delivered in 10 fractions 24 h apart or in a single session. Following a single neutron exposure, leukemias and all carcinomas and sarcomas appeared to increase somewhat more rapidly with dose than after gamma irradiation. No significant difference in the incidence of leukemias and all carcinomas and sarcomas was noted between a single and a fractionated neutron exposure.

Animals↗
PubMed1986

Polysaccharides induce radioprotection of murine hemopoietic stem cells and increase the LD50/30 days.

Intravenous administration of 60 mg/kg of a polysaccharide (MNR, MNZ, GLP/BO4, GLP/BO5) significantly decreases the mortality of mice exposed to a single dose of X rays. The dose reduction factors (DRF) obtained for MNZ, MNR, GLP/BO4, and GLP/BO5 given intraperitoneally 15 min before exposure were 2.16, 1.93, 1.80, and 1.94, respectively. The DRF was not increased when MNZ or GLP/BO4 were combined with injection of AET before X-ray exposure. The LD50 for the CFUs exposed in vivo in mice was 1.13 Gy for the treated mice and 0.75 Gy for the nontreated mice. This corresponds to a DRF of 1.6. The DRF calculated from the slope is 1.27.

Animals↗
PubMed1983

The effects of a fractionated gamma irradiation on life shortening and disease incidence in BALB/c mice.

BALB/c male mice (12 weeks old) were exposed to a single or fractionated exposure of 137Cs gamma rays. The fractionated dose was split into 10 equal doses delivered at an interval of 1 day. The causes and possible causes of spontaneous death were ascertained by autopsy and histological examination, and the data were treated by competing risk analysis. Life shortening followed a linear dose dependency and was about the same for fractionated (38.1 +/- 3.1 days/Gy) as for single (46.2 +/- 4.3 days/Gy) exposure. Death from tumor disease was enhanced and that from nonstochastic lung and kidney diseases was reduced after fractionated compared to single exposure.

Animals↗
PubMed1983

Life shortening and disease incidence in BALB/c mice following a single d(50)-Be neutron or gamma exposure.

Male BALB/c mice, 12 weeks old, were given a single exposure of either 137Cs gamma rays or d(50)-Be neutrons at a dose rate of 3 Gy/min. The animals were kept until death, and causes of death or possible causes of death were ascertained by autopsy and histology. The data were evaluated by competing risk methods. The survival time dose-effect curve for both types of exposure was linear and did not differ significantly (slopes: 55.8 +/- 4.0 days/Gy for neutrons and 46.2 +/- 4.3 days/Gy for gamma rays). The incidence of different diseases also was similar for both groups except that more carcinomas, sarcomas, and myeloid leukemias seemed to occur after neutron exposure and that nonstochastic lung and kidney diseases seemed to arise at lower doses.

Animals↗
PubMed1980

Preleukemic cells and radiation-induced thymoma.

C57B1/Cnb male mice exposed to four weekly doses of 1.75 Gy of whole-body X-irradiation. After different intervals a suspension of bone marrow cells or thymic cells was injected intravenously into C57B1/Rb (6:15)1 Ald male mice expose to 2 Gy to X-rays. The lymphomas in the recipient were analyzed for their genotype by determining the percentage of donor cells in metaphase in the lympho and haematopoietic tissue of the host. No preleukemic cells could be demonstrated in the bone marrow and the thymus of donor mice.

Animals↗
PubMed1978

Repair and biochemical protection in life shortening of mice exposed to fractionated X-irradiation.

Male mice of the BALB/c+ strain were exposed to X-rays at fractionation intervals of 7, 15, 30, and 60 days. One group received a mixture of radioprotectors, another AET (only 30 days fractionation), a third one served as control. The doses ranged, dependent on the treatment, from 300--1500 R. When survival was corrected for acute death, the control and AET treated animals died after an accumulated dose of about 2000 R whereas those treated with a mixture of radioprotectors died after about 4000 tr. Bone marrow failure and lung damage is the main cause of death within the initial 200 days after start of the exposure. At later times, fibrotic changes and in particular glomerulosclerosis are observed.

Animals↗
PubMed1976

[Study of chromosome characteristics of artificially-induced ascite tumors].

Some ascite tumours have been induced in rat by intraperitoneal injection of RadLV and in mouse by intraperitoneal injection of RadLV, or of protozoa such as Trypanosoma brucei and Toxoplasma gondii. Cytological examination of the resulting ascite tumours has shown that chromosome aberrations were associated with the presence of C and A viral particles.

Animals↗