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Biomedical subjects

C W Mays

Publications and source records attributed to C W Mays.

At least 55 records · Page 3Linked to original sources

Failure of interferon to inhibit plutonium-induced osteosarcomas in mice.

The injection of murine interferon three times weekly in dose levels of 1,250, 5,000, or 20,000 U produced no significant antitumor effect against primary 239Pu-induced osteosarcomas in C57BL/6J mice. The interferon treatment was begun 94 days after the plutonium injection, which is well before the radiographic or microscopic appearance of neoplasia, and was continued until the moribund state or death. The average radiation dose accumulated by the skeleton at the time of first treatment was approximately 300 rad. The largest dose of interferon studied, 20,000 U/injection, was approximately 3 X 10(6) U/m2 of body surface, or 10(6) U/kg body weight.

Animals↗

228Th retention and dosimetry in beagles.

Total-body and skeletal retention of 228Th were determined in a group of 104 young adult male and female beagles for about the first 7 years after the injection of 0.00159 to 2.76 muCi/kg. Ratios of 224Ra / 228Th , 212Pb / 228Th , and 212Bi / 228Th in the skeleton and in soft tissues of 20 beagles were measured as a function of time after injection. A humerus, femur, and ulna from 20 dogs dying 7 to 554 days after injection were sectioned, and the 228Th concentration was obtained for each piece. Percentage biological retention in the skeleton of 228Th at t days after injection could be described as 68.1 e-0. 000180t . Ratios of daughter-to-parent activity in soft tissue showed no definite trend with dose level or time and averaged Ra/Th = 0.56, Pb/Th = 0.83, and Bi/Th = 0.91, whereas the ratios for the skeleton varied with both dose level and time. Ratios of activity in the skeleton from lowest to highest dose level after 2 years following injection ranged between Ra/Th = 0.88 to 0.95, Pb/Th = 0.78 to 0.92, and Bi/Th = 0.77 to 0.90. Retained 228Th was deposited most heavily in parts of the skeleton with much trabecular bone, much bone surface area, and high bone remodeling rates. No changes in this deposition pattern could be discerned during the 554 days over which the measurements of sectioned long bones were made.

Animals↗

Retention and dosimetry of injected 241Am in beagles.

Equations have been derived, from the results of total-body and partial-body counting and gamma-ray counting of individual bones and soft tissues, which describe the retention of injected 241Am in the liver, in the nonliver tissue (including skeleton), and in the skeleton of young adult beagles. Retention was found to be dependent upon injection level, and different sets of equations were developed for dogs given about (a) 2.8 microCi/kg (b) 0.9 microCi/kg (c) 0.3 microCi/kg, and (d) 0.1 microCi/kg and less. Liver rention, RL, was characterized by a single exponential equation of the form RL = ce-beta t, with c = 0.49 +/- 0.04 and beta = a function of injection level. Nonliver tissue was assigned a retention equation of the form RNL = d + alpha + J(l - e-mt), with d = 0.102 +/- 0.024 e-1.22t, alpha = 0.41 +/- 0.04, and both J and m as a function of injection level. Skeletal retention was found to be about 0.885 +/- 0.037 of nonliver retention with no significant dependence upon either injection level or time after 241Am injection. Dosimetry equations based on these retention expressions were derived. Individual bones of 55 beagles were assayed at death for their 241Am content for a determination of 241Am distribution within the skeleton.

Americium↗

Removal of Pu and am from beagles and mice by 3,4,3-LICAM(C) or 3,4,3-LICAM(S).

Decorporation of Pu and Am by tetrameric catechoylamide (CAM) ligands has been investigated in beagles and mice. Eight dogs were injected intravenously (iv) with 237 + 239Pu(IV) + 241Am(III) citrate, and 30 min later, pairs of dogs were injected iv with 30 mumole/kg of 3,4,3-LICAM(C) [N1,N5,N10,N14-tetrakis(2,3-dihydroxy-5-sulfobenzoyl)tetr aazatetradecane, tetrasodium salt], 3,4,3-LICAM(S) [N1,N5,N10,N14-tetrakis(2,3-dihydroxy-4-carboxybenzoyl)te traazatetradecane, tetrasodium salt], CaNa3-DTPA, or each of the latter two ligands. Blood was sampled, and excreta were collected for 7 days, at which time the dogs were sacrificed and nuclide retention in liver and nonliver tissue was measured. Groups of five mice were each given 238Pu(IV) or 241Am(III) citrate iv; 3 min later 30 mumole/kg of a CAM ligand was injected intraperitoneally, mice were killed at 24 hr, and separated excreta and tissues were analyzed. In the dogs, average retention at 7 days of the injected Pu and Am, respectively, was as follows: 12 and 70% after treatment with a CAM ligand alone; 30 and 20% after DTPA; 12 and 20% after LICAM(S) plus DTPA; 90 and 89% without a ligand. In the mice, mean retention of the injected Pu and Am, respectively, was as follows: 14 and 66% after treatment with LICAM(C); 21 and 54% after LICAM(S); 91 and 87% without a ligand. In both species, about 99% of net Pu excretion (excretion with ligand - excretion without ligand) promoted in 24 hr by DTPA or LICAM(S) was in the urine, whereas about 10% of net Pu excretion promoted by the less hydrophilic LICAM(C) was in feces. Delayed excretion of both Am and Pu was significant in all ligand-treated dogs. Comparison of the nuclide content of tissues of ligand-treated mice with those of mice killed 3 min after nuclide injection indicated that the CAM ligands chelated circulating Pu and Am and prevented further deposition. In addition, the CAM ligands removed much of the presumably loosely bound Pu present in liver and skeleton at the time of ligand injection. LICAM(C) was more effective in removing Pu from liver and LICAM(S) was more effective in the skeleton. Moderate to severe uremia and histological evidence of cell killing in the distal tubules of the kidney were observed in the four dogs injected once with 30 mumole/kg of LICAM(S).(ABSTRACT TRUNCATED AT 400 WORDS)

Americium↗

Comparative toxicity of 226Ra, 239Pu, 241Am, 249Cf, and 252Cf in C57BL/Do black and albino mice.

Groups of C57BL/Do (black and albino) mice were injected with graded activities of 226Ra, 239Pu, 241Am, 249Cf, or 252Cf and were followed throughout life. Bone sarcoma was the principal radiation-induced end point, and the risks associated with average skeletal doses of the four transuranium radionuclides, relative to radium, were determined. The relative biological effectiveness (RBE) was calculated for each emitter by dividing its risk coefficient (bone sarcomas per 10(6) mouse-rad) by the risk coefficient for 226Ra. Combined data for males and females in both black and albino mice gave the following values +/- SD for the RBE relative to 226Ra = 1.0: 239Pu = 15.3 +/- 3.9, 241Am = 4.9 +/- 1.4, 249Cf = 5.0 +/- 1.4, and 252Cf = 2.6 +/- 0.8. About 70% of the tumors occurred in the axial skeleton, and the risk coefficient for females averaged about four times higher than for males when all five nuclides were included. The RBE of fission fragment irradiation from 252Cf for cancer induction, relative to alpha irradiation, for the combined data in all of the animals given 252Cf and 249Cf, was 0.02 +/- 0.28, in agreement with the calculated theoretical value of 0.03, based on the ratio of summed track lengths in tissue.

Alpha Particles↗

Radium retention in mature beagles injected at 5 years of age.

Retention of 226Ra was substantially lower in mature beagles injected at 5 years of age compared to corresponding values for young adult beagles injected at 17 months of age. As with young adults, the percentage retention in mature dogs given about 10 microCi/kg exceeded that in mature dogs given 4 microCi/kg or less. Percentage retention, R, at t days after the injection of 10 microCi/kg in mature beagles could be represented by the equation, R = 64.1e-0.233t + 13.0e-0.0048lt + 22.9e-0.000329t, and for mature beagles given 4 microCi/kg or less, R = 38.8e-0.40t + 30.6e-0.0424t + 11.9e-0.00567t + 18.7e-0.000352t. Measured 222Rn/226Ra ratios in bone were similar in mature and young adults. Roughly 66% of the injected radium was excreted by mature dogs during the first 3 weeks, about two-thirds of the total excretion appearing in the feces. Distribution of 226Ra within the skeleton was similar in mature and young adult beagles.

Age Factors↗

Radium retention and dosimetry in juvenile beagles.

Retention of administered 226Ra was substantially greater in beagles injected as 3-month-old juveniles than as 1.4-year-old young adults, but the measured 222Rn/226Ra ratio in bone was significantly less in juveniles for about the first 600 days after injection. An equation that describes the total-body biological retention R in beagles injected with 226Ra at 3 months of age at any time t (in days) after injection during the first 6.6 years is R = 0.331e-0.206t + 0.245e-0.00374t + 0.424e-0.000114t. The rate constant of the final term in the equation for juveniles is similar to that for young adults, suggesting that this component reflects the net turnover rate in the slowly remodeling component of adult bone. Compared to young adult beagles, animals injected as juveniles had a greater fraction of their retained 226Ra in parts of the skeleton containing much cortical bone, such as paws, and a smaller fraction in those parts containing much trabecular bone.

Age Factors↗

Radium retention and dosimetry in the St. Bernard.

The percentage total-body retention (R) of 226Ra was determined in 14 young adult St. Bernards for the first 4 years after injection to be represented by the equation, R = 34.8 e-0.165t + 24.6 e-0.00537t + 40.6 e-0.000503t, where t is the time after injection in days. It was found that the 222Rn/226Ra ratio in the skeleton was similar to that measured previously for young adult beagles given 226Ra. Excretion of injected 226Ra averaged about 32% in the first 2 weeks, with about 2/3 of the total appearing in the feces. St. Bernards appear to retain more 226Ra than do beagles injected at the same age. The last two terms of the retention equation were used to calculate the average skeletal radiation dose rate and cumulative radiation dose normalized to each dog's individual retention measurements. Allowance was made in the calculations for the changing skeletal retention of 222Rn and its radioactive daughters as a function of time.

Alpha Particles↗

Incidence of plutonium-induced bone cancer in neutered mice.

The incidence of bone cancer, after a single i.p. injection of monomeric 239Pu citrate, is significantly higher in female than in male mice. To evaluate the role of the gonads in this sex-related difference, male and female C57BL/Do (albino) mice were castrated at 40 days of age. Fifty days later, they were given injections of 239Pu. After castration, the frequency of bone sarcomas in the two sexes was approximately equal. This resulted from an increased incidence in the castrated males and a decreased incidence in the ovariectomized females as compared to the intact plutonium-treated mice.

Animals↗

[The effects of radium-224 in children and adults (author's transl)].

During 1944-1952 a large number of German patients were injected with "Peteosthor", a solution of Ra-224 with added traces of eosin and colloidal platinum. In high doses this treatment has been followed by an increased frequency of malignant bone sarcomas, benign exostoses, growth retardation, tooth breakage, kidney diseases, liver diseases and cataracts. This information is being used to estimate the bone cancer risk from Plutonium.

Adolescent↗

Gamma-ray spectrometry of humans at the University of Utah.

A human total-body counter was designed and built with two 20 X 10 cm NaI (Tl) crystals suspended over an "isoresponse surface" upon which the subject reclines. This surface is curved from head to knee and from left to right, so that a gamma-ray emitting object is detected with equal efficiency when placed anywhere upon it. The positioner and detectors are housed in a low background enclosure constructed of steel 31 cm thick with a graded inner lining of lead + cadmium + copper. Calibration of the system was accomplished by administering trace amounts of various radionuclides to 48 human subjects of various sizes, ranging in age from 4--80 years. Counting rates per retained muCi at 0.53, 0.66, 1.53, and 2.75 MeV (83Rb, 137Cs, 42K, and 24Na) were determined as a function of body size and were compared with counting rates per muCi of corresponding emitters centered in a polyethylene cylinder of radius 10.3 cm. Limits of detection, corresponding to three times the standard deviation of a 50 min background, were 170 nCi 90Sr (via Bremsstrahlung X-rays), 0.78 nCi 131I, 0.48 nCi 83Rb, 0.52 nCi 137 Cs, 4.9 nCi 40K (or 5.8 g of natural potassium) and 1.7 nCi 222Rn.

Body Height↗

Thorotrast-associated sarcoma of bone: A case report and review of the literature.

An osteosarcoma developed near the right lesser trochanter of a 55-year-old woman. The neoplasm fulfilled the generally accepted criteria for a Thorotrast related malignancy. Strengthening this relationship was the occurrence of the tumor in an unusual location and uncommon age group. Thorium was confirmed both in the tumor and in bone marrow histiocytes by its characteristic x-ray spectrum. Including this case only twelve Thorotrast-associated neoplasms of bone have been reported. The mean latency period after Thorotrast administration was 26 years. Regression analysis revealed that latency period and Thorotrast dose are inversely related. All tumors were reported to be sarcomas. Six osteosarcomas, one fibrosarcoma, one chondrosarcoma, and one undifferentiated sarcoma were proven histologically. All patients, for whom follow-up was given, had died of the tumor. The reasons behind the low frequency of reported Thorotrast-associated bone malignancies may be the low concentration of 232Th and radioactive daughters in bone, long latency period or the general lack of knowledge concerning the possible relationship between Thorotrast and bone tumors. Statistical association between Thorotrast injection and bone sarcoma is shown. The criteria for the diagnosis of Thorotrastosis are discussed as well as the long term deleterious effects. The distribution of Thorotrast within the body is discussed as well as the associated radiographic changes.

Adult↗