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PubMedDate not supplied

[The effect of diphosphonates on the metabolism of calcium, its regulation and the state of the bone tissue in the modelling of the physiological effects of weightlessness].

The diphosphonates AMOA and OEDP had a positive action on calcium metabolism and regulation and the osseous tissue in tilt-suspension and hypokinetic Wistar rats in 40-60-day experiments. During special regimens of physical training, ksidifon (OEDP) produced preventive effects on calcium metabolism and renal calciuretic function in man during 120-day antiorthostatic hypokinesia and the agent may be recommended for prevention of alterations in mineral metabolism and osseous tissue at long-term bed rest.

Animals↗
PubMed1977

Interaction of dichloromethylene diphosphonate and vitamin D on bone of thyroparathyroidectomized rats.

Dichloromethylene diphosphonate (Cl2MDP) antagonized the action of vitamin D on bone in thyroparathyroidectomized rats by reducing the metabolic activity of osteoblasts and osteocytes and decreasing the number of osteoclasts. Ultrastructurally, osteoblasts in Cl2MDP-treated rats were interpreted to be less active in bone matrix synthesis. Osteocytes in Cl2MDP-treated rats were interpreted ultrastructurally to be inactive; there was no evidence of bone resorption when compared to osteocytes in rats given vitamin D alone. Abnormal osmiophilic densities in the pericellular bone matrix of rats given vitamin D alone were not present in rats given vitamin D and Cl2MDP. The ultrastructure of osteoclasts was unaltered by Cl2MDT. These cellular changes were associated with a decrease in serum calcium and increase in bone ash and magnesium concentration in rats given high levels (10 mg/kg) of Cl2MDP. Bone adenosine triphosphatase and alkaline phosphatase activities were not affected by Cl2MDP. These results suggest that Cl2MDP may limit the hypercalcemia of hypervitaminosis D by directly inhibiting bone cells in addition to its physicochemical action.

Adenosine Triphosphatases↗
PubMed1977

[Inhibition of mouse spleen inorganic pyrophosphatase by methylene diphosphonic acid].

Some properties of mouse spleen cytosol inorgainc pyrophosphatase (PPi-ase) (E. C. 3.6.1.1) as well as the effect of methylene diphosphonic acid (PCP) on the PPi-ase activity were studied. Specific staining for the enzyme PAAG disc-electrophoresis was developed; it was shown that the PPi-ase formed only one band in 7.5% PAAG. The enzyme pH optimum being 8.0, the optimal [Mg++]/[PPi] ratio was about 2; Km =7.7x10(-4) M, Vmax=0.77 mkM. min-1. mg protein-1. PCP was shown to competitively inhibit the pyrophosphatase reaction, Ki=2.5x10(-4) M +/- 0.2x10(-4) M.

Animals↗
PubMed1991

[Diphosphonates in the treatment of osteoporosis].

The efficacy of diphosphonates in the treatment of diseases with increased osteoclastic bone resorption has been clearly demonstrated. Recent results show that these substances are also effective in the treatment of osteoporosis. Intermittent application of the first generation bisphosphonate, etidronate, up to three years is free of risk, stabilizes trabecular bone density after two years and seems to decrease the progression of deformations of the vertebral column in women with postmenopausal osteoporosis and vertebral fractures. In order to prove this benefit clearly, further studies of longer duration are needed. Continuous application of the second generation bisphosphonate, pamidronate, leads to an increased density of vertebral bodies in osteoporotic patients up to four years and a decreased frequency of new vertebral fractures. These results must however still be confirmed by controlled studies with more patients. There are also indications that a continuous treatment with pamidronate is able to prevent the steroid-induced bone loss. There are on the contrary no results about the effect of bisphosphonates on the fracture rate of peripheral bones and only limited results about the use of bisphosphonates in the prevention of postmenopausal bone loss. Before bisphosphonates can be offered as an alternative solution to hormone substitution therapy, we still need extensive studies about efficacy and safety.

Bone Density↗
PubMed1977

Effect of dichloromethane diphosphonate on calcium homeostatic mechanisms in pregnant cows.

The administration of 4 mg/kg/day of dichloromethane diphosphonate (Cl2MDP) subcutaneously to pregnant cows fed a low-calcium diet significantly reduced bone resorption as indicated by microradiographic evaluation of endosteal surfaces of cross sections of ribs. Plasma parathyroid hormone levels were similar between Cl2MDP-treated and control cows prepartum, during EDTA infusions, and near parturition. Ultrastructurally, chief cells of the parathyroid glands of both groups of cows were in the active stage of the secretory cycle. The chronically stimulated chief cell from cows administered Cl2MDP had a large cytoplasmic area containing many lipofuscin granules and lysosomal bodies and a few secretory granules near the large Golgi apparatus or aligned along the plasma membrane. Uptake of calcium 45 by the duodenal mucosa incubated in vitro was greater in Cl2MDP-treated cows compared to control cows. The administration of Cl2MDP significantly reduced rapidly mobilization calcium reserves. Following an intravenous EDTA infusion and the spontaneous calcium drain associated with parturition and the beginning of lactation, Cl2MDP-treated cows developed severe hypocalcemia. The rapid mobilization of calcium reserves in cows administered Cl2MDP prepartum was impaired mainly because of diminished resorption of bone despite adequate parathyroid hormone secretion in response to severe postpartal or EDTA-induced hypocalcemia.

Animals↗
PubMed1977

Comparison of Tc-99m methylene diphosphonate with Tc-99m pyrophosphate in the detection of acute myocardial infarction: concise communication.

Myocardial scans were obtained in ten patients with proven myocardial infarction. Scintigraphy on consecutive days was performed with technetium-99m methylene diphosphonate and technetium-99m pyrophosphate. Images obtained with the two tracers were generally equal in quality. Those with PPi exhibited denser uptake, while background activity was lower with MDP.

Diphosphates↗
PubMedDate not supplied

[Use of xydiphone diphosphonate for correcting the course of posttraumatic bone regeneration in protracted hypodynamia].

Experiments were conducted on rats to study the effect of daily injection of xydiphone diphosphonate in a dose of 5 mg/100 g on bone tissue in normal motor activity and in hypodynamia caused by amputation of a limb and posttraumatic regeneration. It was established that xydiphone inhibits thinning of the diaphyseal cortical layer induced by hypodynamia and normalizes the parameters which characterize posttraumatic bone tissue regeneration in an unsupported position of the limb.

Animals↗
PubMedDate not supplied

[Dynamic scintigraphy with sodium 1-hydroxy-ethane-1,1 diphosphonate for the differential diagnosis of osteomalacia in patients in the terminal stage of chronic kidney failure].

A total of 28 patients were examined. Of them 17 were exposed to systematic hemodialysis, 11 examinees sustained transplantation of the kidney. Dynamic scintigraphy was performed with a computerized gamma-camera. The authors studied the kinetics of the blood discharge of Tc99m-labelled sodium 1-hydroxyethane-1,1 diphosphonate and its accumulation in the osseous tissue. In supine position of the patient a collimator could demonstrate simultaneously pelvic spines, ortal bifurcations and femoral trochanters. Immediately after the administration of the agent the recording was started: 8 frames for the first 2 min, then 38 frames for 38 min by the matrix 64 X 64. Blood REP levels were found by subtraction of the value of its activity in the projection of postero superior pelvic spine from the values in the site of the aortal bifurcation. The authors revealed that in case of osteomalacia the REP blood elimination coefficient (K1) was less than 0.1 min-1 and proposed to use it for distinguishing osteomalacia from other patterns of renal osteodystrophy. Factors that could change the amount of K1 values are discussed.

Bone and Bones↗
PubMedDate not supplied

[Kinetics of bone uptake of 99m Tc-labeled diphosphonates. Preliminary results].

The bone fixation of diphosphonates depends on the degree of osteogenesis, the blood bone flow and the capillary permeability. The precise characteristics of the fixation kinetic are not very well known. The authors propose a new method which makes possible to study them and expose their results. For average persons the fixation curves present an ascending line, an apex, reach within 40 mn and a descending line. Any affection don't seem to have characteristic curves; on the contrary it is possible to have different curves for a same affection which implies doubtless various anatomic and metabolic data.

Bone Diseases↗
PubMedDate not supplied

[Clinical comparison of the kinetics of 99mTc pyrophosphate and 99mTc methylene diphosphonate (author's transl)].

In a series of 10 patients the hematic and plasmatic clearances of 99mTc-pyrophosphate (PYP) and 99mTc-metylene-diphosphonate (MDP) have been studied. The analysis of the results shows that the elimination both hematic and plasmatic of MDP is significantly faster than that of PYP. Moreover the plasmatic elimination of PYP is faster than its hematic elimination. This fact is probably due to a partial absorption of the radionuclide on the surface of the red cells. No significant differences result in the urinary elimination of both radionuclides. As a consequence the MDP has a lower fundus activity and a lower irradiation dose to the blood and to the whole body. For those reasons this radionuclide is proposed as the preferred agent in bones scintigraphy.

Diphosphates↗
PubMed1979

Comparison of Tc-99m pyrophosphate and Tc-99m methylene diphosphonate in acute myocardial infarction: concise communication.

This study compared Tc-99m pyrophosphate (PPi) and Tc-99m methylene diphosphonate (MDP) for myocardial infarct imaging in 24 patients with diagnosed acute myocardial infarction. The radiopharmaceuticals were administered randomly and interpreted without knowledge of the sequence used. Twenty-three patients (96%) had positive Tc-99m PPi scintigrams, but only 17 (71%) had a positive Tc-99m MDP study (P less than 0.05). In addition, a comparison of the relative intensity with each agent revealed greater intensity with Tc-99m in 21 cases, equal intensity in two cases, and less intensity in only one case (p less than 0.001). These findings support the superiority of Tc-99m PPi as the agent of choice for myocardial scintigraphy in acute infarction.

Acute Disease↗
PubMed1986

Iodine-131-labeled diphosphonates for palliative treatment of bone metastases: II. Preliminary clinical results with iodine-131 BDP3.

The kinetics, dosimetry, and response of iodine-131 alpha-amino-(4-hydroxybenzylidene)-diphosphonate ([131I]BDP3) treatment were investigated with patients who had pain symptoms from bone metastases of various primary carcinoma. The blood clearance of [131I]BDP3 was rapid. More than 90% disappeared from the blood pool at 2 hr after injection. The excretion of the activity occurred solely through the kidneys and mean total-body retention at 48 hr was 48.6%. The urinary activity showed a metabolite which must be formed by an in vivo cleavage reaction of a phosphorus-carbon bond. The uptake of in vivo cleaved [131I]iodide in the unblocked thyroid was approximately 0.5%. The effective half-life of [131I]BDP3 in metastatic bone (median 182 hr; range 177-205 hr) proved to be longer than in unaffected areas (145 hr; 140-165 hr). Palliative therapies were performed with 18 patients. They received doses ranging between 6 and 48 mCi [131I]BDP3. The response was 44% complete pain relief, 6% substantial pain relief, 22% minimal improvement, and 28% no change. The duration of response ranged between 1 and 8 wk.

Benzylidene Compounds↗
PubMed1989

[Diphosphonates. Current trends and therapeutic prospects].

Diphosphonates are compounds characterized by a P-C-P bond. They are thus analogs of pyrophosphate and can be useful for treating several bone diseases. The authors synthetically review the mechanism of action of these drugs and their most important clinical applications. The authors finally mention the interesting therapeutic possibilities deriving from the development of new members of this class.

Bone Diseases↗
PubMed1989

[Diagnosis of osteomalacia using dynamic scintigraphy with diphosphonate in terminal renal insufficiency].

In the diagnosis of osteomalacia in patients with terminal renal insufficiency after the method of dynamic scintigraphy with diphosphonate major emphasis should be placed on the coefficient of RP blood elimination (C1). The disease should be diagnosed in C1 below 0.1 min.-1. A relative increase in the coefficient of cumulative RP in the bones (C2) as compared to C1 (greater than 2-fold) should be regarded an accessory sign in the diagnosis of osteomalacia.

Diphosphonates↗
PubMed1987

Immunomodulation with liposomes: the immune response elicited by liposomes with entrapped dichloromethylene-diphosphonate and surface-associated antigen or hapten.

Macrophages in the murine spleen were eliminated by the intravenous administration of dichloromethylene-diphosphonate (DMDP) encapsulated in liposomes. The immune response against an antigen (bovine serum albumin, BSA) or hapten (dinitrophenyl, DNP) associated with the surface of the DMDP liposomes was studied. Significant effects of macrophage elimination on the primary (IgM), but not on the secondary (IgG), anti-BSA response were found. Dramatic effects on the response against liposome-associated DNP were observed in macrophage-depleted mice. The number of anti-DNP antibody-forming cells in the spleen decreased from 300 to 28 per section, and anti-DNP serum titres dropped to 12% of their normal values. Since a similar phenomenon was observed for TNP-Ficoll, a thymus-independent type-2 antigen (and not for thymus-dependent or thymus-independent type-1 antigens), we suggest that this response should be classified as thymus-independent type-2 on grounds of its in vivo behaviour. We conclude that adjuvant activity (and memory formation) of liposomes with antigen exposed on their surface occurs irrespective of the presence or absence of splenic macrophages, and that DMDP liposomes could be useful in drug targeting with antigenic liposomes.

Animals↗
PubMed1987

Dichloromethylene diphosphonate action in hematologic and other malignancies.

We have studied the administration of both oral and intravenous dichloromethylene diphosphonate (Cl2MDP) in patients with hypercalcemia and/or hypercalciuria due to increased bone resorption in the setting of multiple myeloma (N = 16) or chronic lymphocytic leukemia (N = 1). The effectiveness of 1600 mg of oral Cl2MDP twice daily was studied in 14 subjects with refractory multiple myeloma, active osteolytic disease and either persistent hypercalciuria (urinary Ca greater than 200 mg per g creatine on a low Ca intake) or hypercalcemia (serum Ca greater than 11.0 mg/dl), in a double-blind, placebo-controlled, 16 week-long trial. Of the 12 patients who received Cl2MDP (2 died in the placebo phase), 11 had marked reductions in urinary calcium (P less than 0.001), which fell into the normal range in 9. Urinary hydroxyproline decreased significantly in 8. Eight of the 11 responders also appeared to have decreases in bone pain associated with Cl2MDP therapy. Similar results were found when this protocol was used in a study of 10 women with breast cancer metastatic to bone. In addition, intravenous Cl2MDP was studied in 12 patients with hypercalcemia of malignancy, of whom 2 had multiple myeloma and 1 had chronic lymphocytic leukemia (CLL) associated with extensive osteolytic bone destruction. We gave 2.5 mg/kg on the first treatment day and 5 mg/kg daily thereafter for up to six more days. Serum calcium fell to normal after a mean of four days in the three patients with hematologic malignancies as well as in eight of the nine with solid tumors. Both urinary Ca and OHP also declined significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1987

Duration of effect of oral diphosphonate therapy in Paget's disease of bone.

The effects of the diphosphonates etidronate and clodronate were studied in 144 patients with Paget's disease. All five programmes of treatment tested induced a similar suppression of disease activity as judged by serum alkaline phosphatase concentrations, but the proportion of patients responding and the duration of responses differed significantly between programmes. The proportion responding to etidronate 5-10 mg/kg/day for six months was less than for other regimens, and the most sustained response was after treatment with clodronate 1600 mg daily for six months. More complete biochemical suppression was associated with the more prolonged responses irrespective of the regimen used.

Administration, Oral↗