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At least 955 records · Page 53Linked to original sources
PubMed1983

Effects of ethane-1-hydroxy-1,1-diphosphonate (EHDP) upon the kinetics of bone resorption and bone formation at the whole bone level in prelabelled chicks.

Chicks chronically prelabelled with 45Ca, 3H-tetracycline, and 3H-proline were used to measure the weekly effect of EHDP (5 mg P/kg for 28 days) on bone turnover at the whole bone level in vivo. Direct measurements were made of cortical bone resorption (loss of 3H-tetracycline and 3H-collagen from whole femur, blood-bone ratio of 45Ca), skeletal collagen formation and bone mineralization (collagen and calcium mass per whole femur, respectively). Chicks were sacrificed after 5, 14, 21 and 28 days of EHDP administration. By five days of treatment, EHDP caused a greater inhibition of bone mineralization (86%) than bone resorption (30-39%) without affecting skeletal collagen mass. The blood-bone ratio of 45Ca decreased 34%, which was similar in degree to the inhibition of 3H-tetracycline loss (30%) and 3H-collagen loss (39%). Almost complete inhibition of bone resorption and bone mineralization occurred by 14 days of treatment without effects on skeletal collagen mass. No additional effect was seen at 21 and 28 days of EHDP treatment. In chicks, EHDP inhibits almost completely bone mineralization (bone formation) and cortical bone resorption without affecting skeletal collagen mass.

Animals↗
PubMed1980

Influence of a diphosphonate on the cellular aspect of young bone tissue.

Stimulated by the rather sparse information in the literature on cellular changes induced by EHDP, we carried out electron microscopic investigations on young bone tissue and on de novo bone formation. Cellular changes could be observed during continuous administration of EHDP. The osteoblasts demonstrated temporary storing of crystalloid structures in the mitochondria, and atypical osteocytes showed persistent changes indicative of hyperactivity. The osteoclasts exhibited varying ultrastructural features with respect to the number and appearance of nuclei, Golgi, RER, and lysosomes. These changes under the influence of EHDP could be an indication of altered activity of the osteoclast. The possible interference of EHDP with bone cell metabolism is discussed.

Animals↗
PubMed1976

The metabolic heterogeneity of glycosaminoglycans of the different zones of the epiphyseal growth plate and the effect of ethane-1-hydroxy-1, 1-diphosphonate (EHDP) upon glycosaminoglycan synthesis in vivo.

The synthesis of total and unextractable glycosaminoglycans of rabbit epiphyseal growth plate was studied by determination of the incorporation in vivo of 35S-sulphate into various glycosaminoglycans separated by microfractionation procedures using CPC and ECTEOLA columns. In the narrow hypertrophic zone, hyaluronic acid and chondroitin sulphate of low molecular weight were found to be unextractable with 3M guanidinium chloride for 24 h, thus being firmly bound within the tissue. While the unextractable chondroitin sulphate showed a sharply reduced synthesis rate in the hypertrophic zone compared with that in the columnar and resting zones, a rapid increase in the synthesis of extractable chondroitin sulphate toward the calcification front is indicated. At microfractionation, solubility profiles indicated that the unextractable chondroitin sulphate was of predominantly lower molecular weight and/or charge density compared to that of the whole tissue, most evident in the hypertrophic zone. The distribution pattern of incorporated 35S showed a close correspondence to the distribution of the various chondroitin sulphate fractions both for extracted and unextracted tissue. In the hypertrophic zone, higher radioactivity was found for chondroitin sulphate of predominantly low molecular weight and/or charge density in extracted compared to unextracted tissue. Low doses of EHDP caused no change of distribution of the various glycosaminoglycans but generally inhibited their synthesis.

Animals↗
PubMed1999

Unintentional human skeletal imaging with 99mTc-methylene diphosphonate 45 months beyond expiration.

Eight patients were inadvertently administered, and imaged with, 99mTc-labeled MDP which was 45 months expired. Two cases are presented. All patients were subsequently imaged with normal MDP. The images obtained with expired MDP were clinically acceptable. No differences in scan abnormalities were observed compared with normal MDP for any of the patients. None of the patients suffered any side effects attributable to the expired MDP.

Adult↗
PubMed1976

Studies on photophosphorylation utilizing methylene diphosphonate analogs of ADP and ATP.

Spinach chloroplasts were able to photophosphorylate the ADP analog alpha,beta-methylene adenosine 5'-diphosphate (AOPCP). Phosphorylation of AOPCP was catalyzed by chloroplasts that were washed or dialyzed to remove free endogenous nucleotides. In the presence of glucose, hexokinase, AOPCP and 32Pi, the 32P label was incorporated into alpha,beta-methylene adenosine 5'-triphosphate (AOPCPOP). In contrast to photophosphorylation of AOPCP, the ATP analog AOPCPOP was a poor substrate for the ATP-Pi exchange reaction and its hydrolysis was neither stimulated by light and dithiothreitol nor inhibited by Dio-9. Photophosphorylation of AOPCP was inhibited by the alpha,beta- and beta,gamma-substituted methylene analogs of ATP, while phosphorylation of ADP was unaffected by them. The ATP-Pi exchange was also unaffected by both ATP analogs, while the weak AOPCPOP-Pi exchange was inhibited by the beta,gamma-methylene analog of ATP. Direct interaction of methylene analogs with the chloroplast coupling factor ATPase was indicated by the enzymatic hydrolysis of AOPCPOP on polyacrylamide gels.

Adenosine Diphosphate↗