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Biomedical subjects

R B Holtzman

Publications and source records attributed to R B Holtzman.

At least 37 records · Page 2Linked to original sources
PubMed1983

Distribution and retention in bone of 226Ra and comparison with the ICRP 20 model.

Analyses are presented of the ratios of 226Ra to calcium in over 650 samples of compact and cancellous bone from 66 female and 26 male subjects who had died from less than 1 to 60 yr after first exposure to radium. The 226Ra/Ca ratios were normalized to the terminal 226Ra skeletal content. The 226Ra/Ca ratios for vertebrae were essentially identical to those for other cancellous bone for a given subject. Comparisons of the data with predictions of the ICRP model of alkaline earth metabolism show that for female cancellous bone the normalized 226Ra/Ca ratios tended to be greater than predicted, while those for female cortical bone (femoral and tibial shaft) tended to be less. The data for males were fitted better by the model. A modification of the model to reduce the amount of radium deposited in soft tissue fitted the data better in some respects. A straight line linear least squares fit to the data appeared to fit as well as, or better than, the models. A radiation effect was suggested in that the normalized 226Ra/Ca ratio for vertebrae relative to the ratio expected increased with skeletal absorbed dose for vertebrae. However, no such effect was apparent for compact bone or for the cancellous bone as a whole.

Bone and Bones↗
PubMed1983

Plugged haversian canals and local dose in radium cases.

Haversian canal plugging is a common lesion in bone from human radium cases, signaling vascular damage. Its incidence is correlated with the whole body radium dose. However, since the vascular supply to bone forms an extensive anastomotic plexus facilitating propagation of vascular damage from a primary site of high radium content, we do not know if the degree of plugging is related to the local bone dose. In this report, we compare the incidence of plugging of osteons in different regions (16 sections) of humeri of three radium cases with terminal 226Ra body contents of 0.203, 1.03 and 15.4 muCi to the local dose of radium in adjacent bone sections. While the first and third subjects had received 226Ra only, the second had had a large intake of 228Ra as well. The background incidence of plugging in 35 "normal" humeri from dissecting room populations (45-90 yr) ranged from 0 to 1%, with an average of 0.3%. The least squares linear regression equation for the relation between the percent of canals plugged (PCP) and dose, PCP = (0.00214 +/- 0.00014) rad + (3.26 +/- 3.6), predicts for our three radium cases a development of about 0.002% plugs/rad. The correlation coefficient was very high (r = 0.97, n = 16, P less than 0.01). When normalized to radiation dose from the two decay series, 226Ra and 228Ra appear to be equally effective in producing plugged canals.

Adult↗
PubMed1983

Dolomite toxicity.

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Biological Products↗
PubMed1979

Metabolic balances of cadmium, copper, manganese, and zinc in man.

Balance studies of cadmium, copper, manganese, and zine were carried out under constant dietary conditions in eight adult males during two calcium intake levels of 200 and 800 mg/day and in an additional single case during a calcium intake of 1500 mg/day. The dietary content and the excretions of these elements in urine and stool were determined. The mean dietary content of cadmium was 32.9 micrograms/day, of copper 1020 micrograms/day, of manganese 2130 micrograms/day, and of zinc 12.4 mg/day. The ratio of the fecal/urinary cadmium excretion was approximately 1.5 and the main pathway of excretion of the other three elements was via the intestine, while the urinary excretions were very low. The different trace element balances were either slightly negative or in equilibrium, except that the zinc balances was positive in 50% of the cases. All balances should be considered maximal values, as the losses in sweat were not determined. The calcium intake level had little effect on the excretion and retention of these trace elements.

Adult↗
PubMed1966

Lead-210 and polonium-210 in tissues of cigarette smokers.

Concentrations of lead-210 and polonium-210 in rib bones taken from 13 cigarette smokers were about twice those in six nonsmokers, the polonium-210 being close to radioactive equilibrium with the lead-210. In alveolar lung tissue the concentration of lead-210 in smokers was about twice that in nonsmokers. These differences are attributed to additional intake by inhalation of lead-210.

Humans↗