Osteosarcoma Of Spine Research Articles

Serial radiography has provided us previously with information on the latent period, site of origin, and rate of growth of radiation-induced osteogenic sarcomas in mice (1, 2). We are now using the same technic to investigate the growth and development of osteosarcomas in mice inoculated soon after birth with FBJ virus. This virus was first obtained from a spontaneous osteosarcoma of the thoracic spine of an untreated CFl/Anl mouse (3). An extract of that tumor was injected into 5 mice on the day of birth, and in 2 of them osteosarcomas of the spine developed nine and eleven months later. An extract of the tumor appearing at eleven months was injected into 31 newborn mice, and by nine months bone cancer had developed in 12 of the 24 that survived to weaning. Since that time the oncogenic agent has been transferred by inoculating newborn mice with tumor material that has passed through a 0.45 micron, HA type millipore filter. The fact that electron microscopy demonstrates viral particles both in cellfree extracts and in ultrathin sections of the osteosarcomas (Fig. 1) further supports the opinion that these tumors are indeed caused by a virus. Materials and Methods For the present study 87 CFl/Anl mice received 0.1 ml of cell-free filtrate from virus-induced osteosarcomas soon after birth by intraperitoneal or subcutaneous injection. They have been examined radiographically one to three times a week since they were one day old. Sixty-four of the mice survived to weaning. To increase the number of potential tumors, 28 mice inoculated with FBJ virus at birth were added to the serial radiographic series when they were forty days old, and 14 were added at eighty-six days of age. At the present time there are 37 osteosarcomas among the 106 animals. Ventrodorsal radiographs are taken with the unanesthetized mice held in position by clips extending from the feet to the four corners of a rectangular frame. A beryllium-window rotating anode x-ray tube with 0.5 mm and 1.5 mm focal spots is used without filtration. Kilovoltage varies with the size of the animal, 15 kVp being used for newborn mice which weigh about 1.3 g, and 35 kVp being used for mice weighing 30 g or more. Target-to-film distances range from 12.5 to 15 in., and times from three-twentieth to one second. Living mice are radiographed at 200 mA with larger focal spot; after death 50 m A and the smaller focus are used. No-Screen x-ray film gives good results, but Kodak Type AA Industrial film is far superior for these studies. The air dose for typical exposures on AA film is 1 to 5 R, but we felt that in the present experiment exposures of this magnitude would not jeopardize the results. Ten control mice radiographed repeatedly under the same conditions as the virus-treated mice have not shown any ill effects to date. Radiologic Findings and Discussion

Read full abstract