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Note on the distribution of mineral salts and “bone seeking” radioisotopes in spongious bone tissue
265 NOTE
ON THE
SEEKING”
DISTRIBUTION RADIOISOTOPES A. ENGSTROM
Department
of Medical
OF MINERAL IN SPONGIOUS
SALTS
AND
BONE
“BONE
TISSUE l
and G. BERGENDAHL
Physics, Karolinska
Institutet,
Stockholm, Sweden
Received June 30, 1958
Tm knowledge
of the distribution of the bone-seeking radioisotopes in the mineralized tissues is of fundamental importance for estimating local dose rates given by radioactivity contained in the skeleton. Especially the problem of internal poisoning with QOSr, one of the main fission products and present, among other things, in the radioactive fall out, has recently attracted a great deal of interest. In general it can be stated that microscopic areas in bone with a comparatively low content of mineral salts show a relatively high uptake of radioisotopes, for example %a, V,r, lraBa, 32P0,, %O, and others. These bone structures are termed “reactive bone” or “reactive sites”. The content of mineral salts within microscopic bone specimens has been studied by X-ray microscopy (microradiography) both on a qualitative and quantitative basis [I]. The bone trabeculae in the spongious bone show extensive areas of low mineralization, hence these areas have a high affinity for the radioisotopes. When the hazard of radiation emitted from these isotopes in uivo has to be evaluated, the spongious bone tissue can be considered critical as the radioactive bone lamellae enclose the bone marrow. The distribution of mineral salts within such spongious bone has been studied by microradiography according to our standard procedures. The distribution of radioactive calcium has been studied on the same specimens, both what regards labelling in uivo and in uitro. In general the in vivo and in vitro labelling give the same pattern. In Fig. 1 is shown at a low magnification a section through a vertebral bone and the corresponding radioautogram. It is seen that the structures possessing a relatively low content of mineral salts show a considerable uptake of %a. This specimen was incubated in a %aCl, solution for 2 hours. At higher magnification, Fig. 2, it is seen that the distribution of mineral salts within the thin bone lamellae varies and that the degree of uptake of %a diminishes with increasing mineralization. (In the microradiogram the whiteness of a structure is proportional to its mineral content). Fig. 3 shows the microradiogram and radioautogram of a section of a rib from a dog which three days before the bone biopsy had received %a intraperitoneally. Also here the uptake of isotope follows the same pattern, i.e. lowly mineralized structures have a higher isotope uptake than well mineralized areas. In this specimen, however, the degree of mineralization is fairly homogeneous. 1 This investigation has in part been supported by grant D 700, National Institute of Dental Research, National Institute of Health, Bethesda, hfd., and in part by European Office of Air Research and Jlevelopment Command, Brussels, contract AF 61 (052).15. Experimental
Cell Research 15
266
A. Engstriim and G. Bergendahl
of a 200 ,u thick section of a human vertebral bone showing the : distriFig. l.- --cI, Microradiogram b, Radioautogram of the same sectio 111after bution of ossified tissues (white in the illustration). incubai ion in a WaCl, solution. Mag. 4.5 x . Experimental
Cell Research 15
“Bone seeking” radioisofopes in bone fissue
267
3 Fig. 2.-Leff, Microradiogram of a few bone lamellae in spongious bone showing the varying degi ree of mineralization within the bone structure itself. Righf, Radioautogram of the same secti Ion after in uilro Iabelling with %a. The lowly mineralized areas (greyish) have a relatively hi gh uptake of isotope. Mag. 44 x . Fig. 3.-Left, Microradiogram of a cross section of a rib from dog, given %a intraperitonea 1lY before bone biopsy. Mag. 10 x . Right, Radioautogram of the same section. Experimental
Cell Research 15
268
R. M. Iuerson
Summarizing this and earlier extensive work it is submitted that the bone lamellae in spongious bone have a high uptake of radioisotopes (dried powder of spongious bone has at least twice the radioactivity of powdered compact bone) depending upon the greater number of reactive sites per unit volume in comparison with that of compact bone. This non-uniform distribution of radioisotopes within the bone lamellae has been used for the calculation of the local, internal dose rates given by YSr with the purpose of stating limits for total body burden, e.g. in connection with the fall-out problem [ 11. REFERENCE 1. ENGSTRGM, A., BJ~RNERSTEDT, FL, CLEMEDSON, C.-J. and NELSON, A., Bone and Radiostrontium. Almqvist and Wiksell, Stockholm, John Wiley and Son, New York, 1958.
NUCLEAR
TRANSFER
STUDIES ON ULTRAVIOLET-IRRA4DIATED AMOEBA PROTEUS R. M. IVERSON’S~*~
Laboratoire
de Morphologic
Animale,
Universit.? Libre de Bruxelles,
Bruxelles,
Belgique
Received June 14, 1958
Snmnzsof
the effect of ultraviolet light (UV) upon cells have indicated that the sites of injury are predominantly nuclear [I, 10, 11, 201 although the cytoplasm can also be injured 18, 18, 191. One of the methods employed to determine the site of UV action is the post-irradiation detection of differences in the chemical constituents largely localized in either the nucleus or the cytoplasm. These studies have shown that the synthesis of deoxyribonucleic acid (DNA) is inhibited by UV [12, 14, 151, with a smaller inhibition of the synthesis of ribonucleic acid (RNA) [13]. The question raised by these studies is whether UV, acts independently upon both the DNA and the RNA synthetic sites, or upon the DNA, which then influences the synthesis of RNA and other cellular constituents. This question has been investigated in the present study by nuclear transfers in Amoeba proteus between UV irradiated and unirradiated cells, the effects being observed in survival time and reaction to cytochemical tests. If the effect of UV is primarily nuclear, by replacing the nucleus of an irradiated cell with an unirradiated nucleus one should observe a reversal of UV injury in that cell. Conversely, an irradiated nucleus placed in unirradiated (and enucleated) cytoplasm should injure the cell. Amoeba proteus cells were grown by the method employed in the laboratory of Dr. Brachet [4]. Prior to an experiment the cells were starved for three days in non1 Public Health Service Research Fellow of the National Cancer Institute. 2 It is a pleasure to acknowledge the aid of Dr. J. Brachet and his co-workers during this investigation and of Dr. P. de Fonbrune for instruction in the use of the micromanipulator. 3 Present address: Department of Zoology, University of Miami, Coral Gables 46, Florida, U.S.A. Experimental
Cell Research 15
ON THE
SEEKING”
DISTRIBUTION RADIOISOTOPES A. ENGSTROM
Department
of Medical
OF MINERAL IN SPONGIOUS
SALTS
AND
BONE
“BONE
TISSUE l
and G. BERGENDAHL
Physics, Karolinska
Institutet,
Stockholm, Sweden
Received June 30, 1958
Tm knowledge
of the distribution of the bone-seeking radioisotopes in the mineralized tissues is of fundamental importance for estimating local dose rates given by radioactivity contained in the skeleton. Especially the problem of internal poisoning with QOSr, one of the main fission products and present, among other things, in the radioactive fall out, has recently attracted a great deal of interest. In general it can be stated that microscopic areas in bone with a comparatively low content of mineral salts show a relatively high uptake of radioisotopes, for example %a, V,r, lraBa, 32P0,, %O, and others. These bone structures are termed “reactive bone” or “reactive sites”. The content of mineral salts within microscopic bone specimens has been studied by X-ray microscopy (microradiography) both on a qualitative and quantitative basis [I]. The bone trabeculae in the spongious bone show extensive areas of low mineralization, hence these areas have a high affinity for the radioisotopes. When the hazard of radiation emitted from these isotopes in uivo has to be evaluated, the spongious bone tissue can be considered critical as the radioactive bone lamellae enclose the bone marrow. The distribution of mineral salts within such spongious bone has been studied by microradiography according to our standard procedures. The distribution of radioactive calcium has been studied on the same specimens, both what regards labelling in uivo and in uitro. In general the in vivo and in vitro labelling give the same pattern. In Fig. 1 is shown at a low magnification a section through a vertebral bone and the corresponding radioautogram. It is seen that the structures possessing a relatively low content of mineral salts show a considerable uptake of %a. This specimen was incubated in a %aCl, solution for 2 hours. At higher magnification, Fig. 2, it is seen that the distribution of mineral salts within the thin bone lamellae varies and that the degree of uptake of %a diminishes with increasing mineralization. (In the microradiogram the whiteness of a structure is proportional to its mineral content). Fig. 3 shows the microradiogram and radioautogram of a section of a rib from a dog which three days before the bone biopsy had received %a intraperitoneally. Also here the uptake of isotope follows the same pattern, i.e. lowly mineralized structures have a higher isotope uptake than well mineralized areas. In this specimen, however, the degree of mineralization is fairly homogeneous. 1 This investigation has in part been supported by grant D 700, National Institute of Dental Research, National Institute of Health, Bethesda, hfd., and in part by European Office of Air Research and Jlevelopment Command, Brussels, contract AF 61 (052).15. Experimental
Cell Research 15
266
A. Engstriim and G. Bergendahl
of a 200 ,u thick section of a human vertebral bone showing the : distriFig. l.- --cI, Microradiogram b, Radioautogram of the same sectio 111after bution of ossified tissues (white in the illustration). incubai ion in a WaCl, solution. Mag. 4.5 x . Experimental
Cell Research 15
“Bone seeking” radioisofopes in bone fissue
267
3 Fig. 2.-Leff, Microradiogram of a few bone lamellae in spongious bone showing the varying degi ree of mineralization within the bone structure itself. Righf, Radioautogram of the same secti Ion after in uilro Iabelling with %a. The lowly mineralized areas (greyish) have a relatively hi gh uptake of isotope. Mag. 44 x . Fig. 3.-Left, Microradiogram of a cross section of a rib from dog, given %a intraperitonea 1lY before bone biopsy. Mag. 10 x . Right, Radioautogram of the same section. Experimental
Cell Research 15
268
R. M. Iuerson
Summarizing this and earlier extensive work it is submitted that the bone lamellae in spongious bone have a high uptake of radioisotopes (dried powder of spongious bone has at least twice the radioactivity of powdered compact bone) depending upon the greater number of reactive sites per unit volume in comparison with that of compact bone. This non-uniform distribution of radioisotopes within the bone lamellae has been used for the calculation of the local, internal dose rates given by YSr with the purpose of stating limits for total body burden, e.g. in connection with the fall-out problem [ 11. REFERENCE 1. ENGSTRGM, A., BJ~RNERSTEDT, FL, CLEMEDSON, C.-J. and NELSON, A., Bone and Radiostrontium. Almqvist and Wiksell, Stockholm, John Wiley and Son, New York, 1958.
NUCLEAR
TRANSFER
STUDIES ON ULTRAVIOLET-IRRA4DIATED AMOEBA PROTEUS R. M. IVERSON’S~*~
Laboratoire
de Morphologic
Animale,
Universit.? Libre de Bruxelles,
Bruxelles,
Belgique
Received June 14, 1958
Snmnzsof
the effect of ultraviolet light (UV) upon cells have indicated that the sites of injury are predominantly nuclear [I, 10, 11, 201 although the cytoplasm can also be injured 18, 18, 191. One of the methods employed to determine the site of UV action is the post-irradiation detection of differences in the chemical constituents largely localized in either the nucleus or the cytoplasm. These studies have shown that the synthesis of deoxyribonucleic acid (DNA) is inhibited by UV [12, 14, 151, with a smaller inhibition of the synthesis of ribonucleic acid (RNA) [13]. The question raised by these studies is whether UV, acts independently upon both the DNA and the RNA synthetic sites, or upon the DNA, which then influences the synthesis of RNA and other cellular constituents. This question has been investigated in the present study by nuclear transfers in Amoeba proteus between UV irradiated and unirradiated cells, the effects being observed in survival time and reaction to cytochemical tests. If the effect of UV is primarily nuclear, by replacing the nucleus of an irradiated cell with an unirradiated nucleus one should observe a reversal of UV injury in that cell. Conversely, an irradiated nucleus placed in unirradiated (and enucleated) cytoplasm should injure the cell. Amoeba proteus cells were grown by the method employed in the laboratory of Dr. Brachet [4]. Prior to an experiment the cells were starved for three days in non1 Public Health Service Research Fellow of the National Cancer Institute. 2 It is a pleasure to acknowledge the aid of Dr. J. Brachet and his co-workers during this investigation and of Dr. P. de Fonbrune for instruction in the use of the micromanipulator. 3 Present address: Department of Zoology, University of Miami, Coral Gables 46, Florida, U.S.A. Experimental
Cell Research 15