strontium-radioisotopes and Disease-Models--Animal

Strontium 90 ((90)Sr) remains in the environment long after a major nuclear disaster occurs. As a result, populations living on contaminated land are potentially exposed to daily ingesting of low quantities of (90)Sr. The potential long-term health effects of such chronic contamination are unknown. In this study, we used a mouse model to evaluate the effects of (90)Sr ingestion on the immune system, the animals were chronically exposed to (90)Sr in drinking water at a concentration of 20 kBq/l, for a daily ingestion of 80-100 Bq/day. This resulted in a reduced number of CD19(+) B lymphocytes in the bone marrow and spleen in steady-state conditions. In contrast, the results from a vaccine experiment performed as a functional test of the immune system showed that in response to T-dependent antigens, there was a reduction in IgG specific to tetanus toxin (TT), a balanced Th1/Th2 response inducer antigen, but not to keyhole limpet hemocyanin (KLH), a strong Th2 response inducer antigen. This was accompanied by a reduction in Th1 cells in the spleen, consistent with the observed reduction in specific IgG concentration. The precise mechanisms by which (90)Sr acts on the immune system remain to be elucidated. However, our results suggest that (90)Sr ingestion may be responsible for some of the reported effects of internal contamination on the immune system in civilian populations exposed to the Chernobyl fallout.

Topics: Animals; B-Lymphocytes; Disease Models, Animal; Humans; Immune System; Mice; Radiation Exposure; Spleen; Strontium Radioisotopes

Topics: Animals; Disease Models, Animal; Dogs; Gingival Neoplasms; Injections, Intravenous; Neoplasms, Radiation-Induced; Radiation Dosage; Strontium Radioisotopes; Tooth Loss

The aim of this study was to evaluate the contribution of a low calcium diet to the cortical and trabecular osteoporosis seen in ovariectomized rats after 7 weeks on a low calcium diet and to investigate the effects of the bisphosphonate clodronate on this development of osteoporosis. Thirty-six mature, female Wistar rats were randomized into four groups: Ovx-B (bisphosphonate) and Ovx-C (control) were ovariectomized, and Sham-Ca (low calcium) and Sham+Ca (normal calcium) were sham operated. The first three groups were fed a low calcium diet (0.01%) and Sham+Ca normal rat chow (Ca 1.1%). The Ovx-B received 10 mg/kg s.c. clodronate daily for nine weeks, and Ovx-C, Sham-Ca, and Sham+Ca received the same volumes of saline. Bone mineral turnover measured as 85Sr-uptake was increased in all low calcium groups compared to Sham+Ca. The Sham+Ca femora had higher dry weight and ash weight than the other groups, and Ovx-C had higher dry weight compared with Ovx-B and Sham-Ca. Calcium content was lower in both Ovx groups compared to both Sham groups. Magnesium was lower in all groups compared to Sham+Ca and higher in Ovx-B compared with Ovx-C. In the femoral shaft, Sham+Ca had significantly higher ultimate bending moment, energy absorption, and deflection compared to the other three groups. Ultimate bending moment was higher in Sham-Ca than in Ovx-C. Stiffness was increased in both Sham+Ca and Ovx-B compared to Ovx-C. The maximum stress in the femoral midshaft was higher in Sham+Ca than in the other groups, and higher in Ovx-B than in Ovx-C. Histomorphometry showed increased medullary area in all low calcium groups compared to Sham+Ca and larger cortical area in Sham+Ca and Ovx-B compared to Ovx-C. Compared to Sham+Ca the trabecular bone volume was decreased to 30% in Sham-Ca and to 9% in Ovx-C, but was unchanged in Ovx-B. The low calcium diet generally increased bone mineral turnover and reduced the tibial bone volume. Femoral changes led to a reduction of cortical fracture strength and maximal stress. Ovariectomy in addition to a low calcium diet reduced femoral strength even more. Daily injections of clodronate to ovariectomized rats on a low calcium diet increased femoral shaft stiffness and maximum stress, and clodronate preserved both trabecular and cortical tibial bone volume completely.

Topics: Animals; Calcium, Dietary; Clodronic Acid; Disease Models, Animal; Female; Femur; Osteoporosis; Ovariectomy; Rats; Rats, Wistar; Strontium Radioisotopes; Tibia

The Periosteum or periosteal membrane is a continuous composite fibroelastic covering membrane of the bone to which it is intimately linked. It consists of multipotent mesodermal cells (11, 15). Although the bone cortex is the main beneficiary of the principal anatomical and physiological functions of the periosteal membrane, the behaviour of the entire bone remains closely influenced by the periosteal activity. These principal functions are related to the cortical blood supply, osteogenesis, muscle and ligament attachments. Through its elastic and contractile nature, it participates in the maintenance of bone shape, and plays an important role in metabolic ionic exchange and physiological distribution of electro-chemical potential difference across its membranous structure. It has also been suggested that the periosteum may have its own specific proprioceptive property. This presentation will study the histo-anatomy and physiology of the periosteum and will discuss in detail its main functions of cortical blood supply and osteogenesis (fig. 1 and 2). It will also present the third intermediary report on a current study of the quantification of cortical vascularisation of femoral bone via the periosteum, using an isotonic salt solution of 85Strontium. The afferent-efferent (arterio-venous) flows of this solution in the thigh vascular system of guinea pigs were measured by gamma spectrometry after a series of selective macro and micro injections of radioactive salt into the femoral arterial system were carried out. Each vascular territory was meticulously selected and the injections were made according to size, starting with the larger vessels, with or without ligatures of neighbouring vessels, going progressively to smaller and smaller vessels not exceeding 100m in diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Vessels; Disease Models, Animal; Elastic Tissue; Electrochemistry; Female; Femur; Guinea Pigs; Ion Transport; Ligaments; Male; Microcirculation; Muscle, Skeletal; Osteogenesis; Periosteum; Proprioception; Regional Blood Flow; Strontium Radioisotopes

Intraoperative radiation therapy (IORT) research is limited by the lack of small-animal models. We have implanted B16 melanoma into mouse kidneys, which we subsequently operated upon and irradiated with beta rays from a 90Sr ophthalmic applicator. The IORT has effectively prolonged survival and produced some cures. The strategy should be applicable to other murine tumors and to other internal implantation sites.

Topics: Animals; Disease Models, Animal; Female; Intraoperative Care; Kidney Neoplasms; Melanoma; Mice; Mice, Inbred C57BL; Neoplasm Transplantation; Radiotherapy Dosage; Strontium Radioisotopes

Topics: Animals; Cesium Radioisotopes; Coronary Circulation; Digoxin; Disease Models, Animal; Dogs; Electrocardiography; Heart Ventricles; Hemodynamics; Microspheres; Myocardial Contraction; Myocardial Infarction; Strontium Radioisotopes

Using a rabbit model, previous studies showed steroid-induced hyperlipidemia with subsequent fatty embolization of the subchondral arteries and hypertrophy of the marrow fat cells, followed by elevation of femoral head pressure from the normal level of 25 cm to nearly 60 cm H2O after eight weeks of treatment. This has led us to believe that pressure changes lead to decreased blood flow in the femoral head. In our study of 22 New Zealand white adult rabbits, weighing an average of 4.0 kg, 14 received a weekly dose of 12.45 mg of methylprednisolone (Depo-Medrol), and eight served as control. Femoral head blood flow was established using the radioactive microsphere technique. Control and cortisone-treated rabbits had femoral head blood flow measured 6, 8 and 10 weeks after treatment. The average blood flow in the control femoral heads averaged 0.2039 +/- 0.076 ml/min/gm, with no difference in the left side and the right side. In the treated group, the average blood flow at ten weeks was 0.162 +/- 0.039 ml/min/gm on the right and 0.164 +/- 0.037 ml/min/gm on the left, which was significantly different. This is parallel to unpredictable clinical findings in human beings.

Topics: Animals; Disease Models, Animal; Femur Head; Femur Head Necrosis; Hyperlipidemias; Methylprednisolone; Microspheres; Pressure; Rabbits; Strontium Radioisotopes; Time Factors

The four existing animal models of cyclic hematopoiesis are briefly described. The unusual erythropoietin (Ep) responses of the W/Wv mouse, the Sl/Sld mouse, and cyclic hematopoietic dog are reviewed. The facts reviewed indicate that the bone marrow itself is capable of influencing regulatory events of hematopoiesis.

Topics: Anemia; Animals; Bone Marrow; Bone Marrow Cells; Disease Models, Animal; Dog Diseases; Dogs; Erythropoiesis; Erythropoietin; Hematopoiesis; Humans; Hypoxia; Lithium; Mice; Mice, Inbred Strains; Mink; Neutropenia; Periodicity; Prednisolone; Strontium Radioisotopes

A new rapid method for producing myocardial necrosis in rabbits was developed, using percutaneous intramyocardial injection of vasopressin in peanut oil. The 15-min procedure resulted in a mortality rate of 15% and a success rate among surviving animals of 50%. When the lesions were 24 hr old, strontium-85 and a technetium-99m-tagged agent were injected intravenously simultaneously, and the animals were killed 1,6, and 24 hr later for tissue radioassay. Strontium-85 failed to accumulate appreciably in the lesions. Three bone-seeking technetium complexes (pyrophosphate, methylene diphosphonate, and imidodiphosphonate) produced lesion-to-normal myocardial ratios of 6,5, and 14, respectively, at 1 hr, and 20,30, and 33 at 6 hr. The ratios for 99mTc-glucoheptonate were only 2 at 1 hr and 4 at 6 hr, while the ratios of 99mTc-acetylcysteine and 99mTc-citrate were even lower.

Topics: Animals; Citrates; Cysteine; Diphosphates; Diphosphonates; Disease Models, Animal; Myocardial Infarction; Rabbits; Radionuclide Imaging; Strontium Radioisotopes; Sugar Acids; Technetium; Vasopressins

Activity levels of 99TC-labeled compounds, 18F, and 85Sr were obtained at 1, 3, and 5 hr. postinjection in normal and healing fractured bone and in soft-tissue rat specimens. Serial diagnostic bone images and blood and urine kinetics were obtained in patients with each of the TC-labeled compounds. Computer-processed images were used to evaluate in vivo kinetics. 99mTC pyrophosphate provides the best overall characteristics for bone imaging. Improved quality and bioassay procedures are required, however, before any one agent can be designated the radiopharmaceutical of choice for diagnostic bone imaging.

Topics: Animals; Diphosphates; Disease Models, Animal; Fluorine; Fractures, Bone; Humans; Isotope Labeling; Kinetics; Phosphates; Radioisotopes; Radionuclide Imaging; Rats; Strontium Radioisotopes; Technetium; Tibial Fractures; Wound Healing

A transplantable myelogenous leukemia of an inbred Wistar/Furth rat has been established in tissue culture and cloned. The resulting transplantable leukemia line demonstrates in vitro doubling time of 20 hr, colony-forming efficiency of 5% in liquid and methylcellulos-containing medium, and a saturation density of 3.0 x 106 cells/sq cm in liquid medium. Following intraperitoneal inoculation, newborn rats developed solid tumors, ascities, and leukemia with ld50 of5 x 103 cells and mean latency of 60 days. The tumor cell morphology was consistent with that of acute myelogenous leukemia. Histochemical staining for myeloid enzymes revealed no evidence of myeloperoxidase, esterase, or leukocyte alkaline phosphatase; however, fluorescent antibody staining for lysozyme was markedly positive. Serum, urine, and ascitic fluid from rats with transplanted leukemia also contained elevated levels of lysozyme. There was no detectable type-CRNA virus production by this cell line after as long as 100 days in vitro. This inbred rat myelogenous leukemia should provide a useful model for studies of chemotherapy and immunoltherapy of human acute myelogenous leukemia.

Topics: Animals; Animals, Newborn; Ascitic Fluid; Cell Division; Cell Line; Culture Media; Culture Techniques; Disease Models, Animal; DNA; Female; Fluorescent Antibody Technique; Histocytochemistry; Leukemia, Experimental; Leukemia, Myeloid, Acute; Leukocytes; Muramidase; Pregnancy; Rats; Retroviridae; RNA-Directed DNA Polymerase; Staining and Labeling; Strontium Radioisotopes; Urine

The concentration of 99mTc-pyrophosphate was determined in the lower extremities of rabbits (normal, abacterial and bacterial affected soft tissues), in osteoarthritis of the hip joint (capsule and muscle) as well as in knee joint effusions. Compared with the 85Sr-concentration, reflecting the calcification capacity, concentrations of 99mTc-pyrophosphate in soft tissues were found to be lower 2 hours p.i., but were up to elevenfold higher 24 hours p.i. These findings should be due to a fixation of 99mTc-pyrophosphate in collagen containing tissues as in the soft tissue tumors (myosarcoma, synvialioma, breast cancer) presented. A mechanism of delayed equilibration could explain augmented uptake in lymph-edema, ascites and effusions in florid osteoarthritis of the knee joint. The possible dependence of 99mTc-pyrophosphate concentration in bone and soft tissue on collagenous contents is discussed.

Topics: Animals; Ascites; Bone and Bones; Breast Neoplasms; Diphosphates; Disease Models, Animal; Extremities; Freund's Adjuvant; Hip; Humans; Joint Diseases; Joint Prosthesis; Joints; Knee; Osteoarthritis; Phosphates; Rabbits; Rhabdomyosarcoma; Sarcoma, Synovial; Strontium; Strontium Radioisotopes; Technetium; Tibial Fractures; Time Factors; Tin

Topics: Acute Disease; Animals; Arthus Reaction; Cardiac Catheterization; Choroid; Chronic Disease; Disease Models, Animal; Eye; Immunization; Inflammation; Injections; Microspheres; Rabbits; Regional Blood Flow; Serum Albumin, Bovine; Strontium Radioisotopes; Uvea; Uveitis; Vitreous Body

Topics: Animals; Blood Pressure; Cardiac Catheterization; Cardiac Output; Cardiac Tamponade; Cerium; Coronary Circulation; Disease Models, Animal; Dogs; Heart; Microspheres; Myocardium; Pericardium; Radioisotopes; Scandium; Shock, Hemorrhagic; Strontium Radioisotopes

Topics: Animals; Blood Gas Analysis; Blood Transfusion, Autologous; Blood Volume; Cerium Isotopes; Chromium Radioisotopes; Disease Models, Animal; Dogs; Hemodynamics; Iodine Radioisotopes; Lung; Microspheres; Oxygen Consumption; Pulmonary Circulation; Radioisotopes; Respiration; Respiratory Dead Space; Scandium; Shock, Hemorrhagic; Strontium Radioisotopes; Ventilation-Perfusion Ratio