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S A Book

Publications and source records attributed to S A Book.

At least 37 records · Page 2Linked to original sources
PubMed1984

Squamous cell carcinoma in the jaws of beagles exposed to 90Sr throughout life: beta flux measurements at the mandible and tooth surfaces and a hypothesis for tumorigenesis.

We present the first detailed dose-response measurements for 90Sr-induced soft tissue tumors other than hemopoietic dyscrasias in chronically exposed beagles. Twenty-four of 387 dogs exposed to 90Sr beginning in utero and by continuous ingestion to 540 days of age developed squamous cell carcinoma of the jaw during their lifetime. Eleven of the 24 tumors were observed in dogs ingesting 12 microCi/day and receiving cumulative average doses of 6500-12,000 rad. None of these tumors was observed in dogs ingesting less than 1.25 microCi/day and receiving cumulative skeletal average doses of 2100-3900 rad, but four were observed at this level. The teeth of these animals acquired a 90Sr burden that is not removed by skeletal remodeling. Measurements of the radiation dose to soft tissue adjacent to the mandible and teeth of dogs chronically fed 90Sr indicated the first 10 micron of soft tissue adjacent to teeth received a radiation dose initially about the same as the average skeletal doses. By 2000-3000 days, these tissues received about two to three times that calculated for the average skeletal dose, or about four to six times the mean marrow dose. We suggest that these tumors arise from epithelial rests, which are embryonic tissue trapped in the periodontal membrane between teeth and bone.

Administration, Oral↗
PubMed1983

Lifetime bone cancer dose-response relationships in beagles and people from skeletal burdens of 226Ra and 90Sr.

The life-time tumor dose-response relationships observed in beagles injected with 226Ra or fed 90Sr at the University of California, Davis, provide a basis for understanding the induction of bone cancer for these bone-seeking radionuclides and for scaling to people. In these studies 385 dogs were exposed to graded dosage levels of 90Sr and 243 dogs were exposed to graded dosage levels of 226Ra with a total of 159 unexposed controls. The results show different dose-response relationships for bone cancer for the two radionuclides based upon the gravimetric average dose rates and cumulative doses to bone. These relationships were found to be well represented by three-dimensional log-normal dose-response surfaces that yield risk as a function of average dose-rate and time after beginning of exposure. All dose-rates suggested a 100% risk at some later time post-exposure but the time required to reach a given level of risk was long for low dose rates so that there exists a practical threshold in that at lower dose rates individuals may die spontaneously from causes associated with natural aging prior to the expected appearance of radiogenic cancer. The risks to people at various 226Ra body burdens (average skeletal dose rates) are estimated based on the model.

Animals↗
PubMed1983

Iodine-129 uptake and effects of lifetime feeding in rats.

Irradiation of thyroid glands in rats at a dose rate of approximately 1 rad/day from continually ingested 129I resulted in no significant increase in thyroid tumors compared to controls, nor in other thyroidal effects, nor was there any difference in longevity between the two groups. Marked decreases in 131I uptake by thyroid glands of 129I-fed rats were observed, but these decreases reflected "blocking" of the thyroid by the large quantities of iodine required because of the low specific activity of 129I. In view of the lack of effects on the thyroid gland invoked by lifetime exposures to 129I, and considering the low specific activity of the radionuclide and the limited capacity of the thyroid gland for iodine, the hazard from 129I appears to be extremely limited.

Administration, Oral↗
PubMed1980

Bone cancer from radium: canine dose response explains data for mice and humans.

Analysis of lifetime studies of 243 beagles with skeletal burdens of radium-226 shows that the distribution of bone cancers clusters about a linear function of the logarithms of radiation dose rate to the skeleton and time from exposure until death. Similar relations displaced by species-dependent response ratios also provide satisfactory descriptions of the reported data on deaths from primary bone cancers in people and mice exposed to radium-226. The median cumulative doses (or times) leading to death from bone tumors are 2.9 times larger for dogs than for mice and 3.6 times larger for people than for dogs. These response ratios are well correlated with the normal life expectancies. The cumulative radiation dose required to give significant risk of bone cancer is found to be much less at lower dose rates than at higher rates, but the time required for the tumors to be manifested is longer. At low dose rates, this time exceeds the normal life-span and appears as a practical threshold, which for bone cancer is estimated to occur at an average cumulative radiation dose to the skeleton of about 50 to 110 rads for the three species.

Animals↗
PubMed1977

Age related changes in serum throxine and 125I-triiodothyronine resin sponge uptake in the young dog.

Serum thyroxine (T4) concentrations and 125I-labelled triiodothyronine resin sponge uptakes (T3-RSU) were determined in young dogs every 10 days between 3 and 103 days of age. When compared to the adult mean of 1.7 microgram T4/100 ml serum, the T4 in young dogs was elevated throughout the ages studied. The serum T4 concentration was twice the adult value at 3 days of age, rose to over five times the adult value in the 1st month of life, and declined again to twice the adult mean by 103 days of age. Serum T3-RSU values decreased from 52% at 3 days (approximately equal to the adult mean) to about 30% from 13 to 23 days, indicating an increase in the thyroid hormone binding capacity of serum proteins in the first few weeks of life. Thereafter, T3-RSU rose to near 50% again. The change in binding capacity appeared to explain, at least in part, the apparent hyperthyroid-like T4 concentrations of the young dog.

Age Factors↗
PubMed1976

Influence of age on thyroidal 131I uptake in Beagle pups.

Parameters in radioiodine metabolism by the thyroid gland were investigated in 98 beagle pups 0-110 da of age and in 6 adults. Significant age-related differences in thyroidal 131I uptake, uptake/g of thyroid, and retention and subsequent radiation dose were observed. Significant differences were also found in uptake/g, retention and subsequent radiation dose were observed. Significant differences were also found in uptake/g, retention, and dose between litters of the same age. Seventy-da-old pups had the highest mean uptake (approximately 25% of the administered dose) and fastest release rate (effective half-life approximately 3.6 da), whereas neonates less than 12 hr of age showed the highest peak concentration (157% of administered dose/g thyroid). The calculated radiation doses to the thyroid were highest in newborn pups, averaging over 100 rads per microcurie of 131I administered, or about 10 times the dose/muCi for adults.

Aging↗
PubMedDate not supplied

Scaling toxicity from laboratory animals to people: an example with nitrogen dioxide.

Published data on the toxicity of nitrogen dioxide (as a model compound) from five laboratory animal species were utilized to scale the relationship of dose and toxic effect to the human species. A minute volume of inspired air was used as a metabolic scaling factor, predicting a median lethality during the time of exposure of 174 ppm NO2 for a 1-h exposure for people. This work demonstrates a method of predicting effects in people when only data for laboratory animals exist. It also shows the value of planning toxicology studies that utilize several animal species, so that their data may be applied to forecasting the human condition.

Animals↗