Ga-67 scans were performed at three-month intervals in a 52-year-old man with an extensively aggressive variant of multiple myeloma, characterized by anaplastic tumor cells, less increase in serum levels of monoclonal IgA than might be expected from an extensive growth of extraosseous lesions, fever without evidence of infection, and short survival time. The findings on the Ga-67 study showed a rapid extension of extraosseous lesions during this aggressive phase. Aggressive multiple myeloma should be included in the list of clinical applications of Ga-67 citrate to tumor imaging.
In hyperthermic treatment of malignant tumors, thermal tissue injury increases dramatically with every degree that the tissue increases above 42.5 °C. Accurate temperature monitoring during hyperthermia is important. Generally, tissue temperature is monitored by inserting sensors into the target tissue ; however, the painful procedure is not tolerated by some patients. We devised a noninvasive method to monitor tissue temperature during radio-frequency hyperthermia. The method functions by detecting the magnetic field induced by the radio-frequency currents that flow through the heated tissue. This technique uses small multi-channel coil antennas to detect radio-frequency currents and generates a two-dimensional image of their distribution in the tissue. The temperature distribution was estimated from the temperature increase and the intensity of the current of the radio frequency. A 4 % agar phantom was used as a model for target tissue receiving hyperthermic treatment. Around the agar phantom, 16 small coils were arranged in a ring. A rectifying circuit and a leveling circuit were connected to each coil antenna, and the current was converted with a fixed resistance into voltage. Since the voltage output from each antenna was attenuated at 1/2πr (r : distance from the radio-frequency current), single-peaked projection data were prepared. After treatment with various signals, radio-frequency currents that flowed through the heated object were determined as a two-dimensional current distribution profile by back-projection. When the insertion of an iron rod into the agar phantom produced a hot spot, the current distribution was examined and compared with the two-dimensional temperature distribution evaluated by thermography. A good correlation was observed between the distribution of radio-frequency currents detected by the coil antennas and the temperature distribution detected by thermography. The linear relationship observed in this study between the two-dimensional distribution of radio-frequency currents and the thermographic temperature distribution suggests the possibility of non-invasive evaluation of temperature distribution in the hypothermic target and the clinical usefulness of this method for temperature monitoring during hyperthermia.
PTH receptors on two stable clonal rat osteosarcoma cell lines, ROS 17/2 and ROS 17/2.8, were characterized using an HPLC-purified, synthetic, sulfur-free, radioiodinated analog of bovine PTH, [Nle8,Nle18,Tyr,34]bovine PTH-(1–34)amide. PTH binding is specific for PTH agonists and antagonists and is dependent on the time and temperature of incubation. There is an excellent correlation between binding affinities of PTH agonists and antagonists in these intact cell systems with those in canine renal membranes. Peptides unrelated to PTH do not bind. Both ROS 17/2 and 17/2.8 have a single class of saturable, high affinity PTH binding sites that, by kinetic analysis and Scatchard analysis of saturation and competition studies, has a dissociation constant (Kj) of 0.8–1.4 nM. Bmax is approximately 36,000 and 72,000 sites per cell in ROS 17/2 and 17/2.8, respectively. A close correlation was found between the binding of PTH agonists to their receptors in ROS 17/2 cells with their relative biological potencies as measured by stimulation of adenylate cyclase in plasma membranes prepared from these cells. Prolonged treatment of ROS 17/2 and 17/2.8 cells with PTH agonists results in a dose- and time-dependent decrease of available cell-surface binding sites, without alterations in Kd. PTH antagonists do not regulate PTH receptors. Regulation of PTH receptors by PTH agonists is dependent on the dose and time of exposure to ligand over a dose range of 10-8 to 10-11 M. Cells exposed to agonists (≥10-8 M) for 48 h show maximally decreased receptor number; continued exposure to agonists (≥10-8 M) does not further decrease PTH receptor number, which remains constant at about 15% of control values. Agonist-induced downregulation occurs with less than 10"11 M agonists, a concentration less than 10% of the minimal dose detected by direct ligand competition. Treatment of ROS 17/2 cells with PTH agonists results in a dose- and time-dependent decrease of PTH-stimulated adenylate cyclase. This agonist-induced desensitization correlates closely with the decreased availability of PTH receptors: it is maximal in cells exposed to agonists (>10-8 M) for 48 h and also does not decrease further with continued exposure of the cells to agonist. Future studies with these stable ROS cell lines should permit detailed analysis of the biochemical mechanisms underlying homologous and heterologous regulation of PTH receptors and desensitization and sensitization of the adenylate cyclase response. (Endocrinology122: 1208–1217, 1988)
Abstract The effects of glucocorticoids on parathyroid hormone (PTH) receptors was studied using rat osteosarcoma-derived cells (ROS 17/2), which have an osteoblastic phenotype, and [125I][Nle8, Nle18, Tyr34]bovine(b)PTH-(1–34)amide as the radioligand. Treatment of cells with physiologic concentrations of hydrocortisone resulted in a time and dose-dependent increase in PTH binding. The increase in PTH binding could be observed by 10 h of exposure to hydrocortisone (2 × 10−7 M), was maximally enhanced by 48 h, and was maintained for the subsequent 7 days of continuous exposure to the steroid. With removal of hydrocortisone, PTH receptor binding promptly returned toward control levels. The increase in PTH binding was attributed to an increase in the availability of receptor binding sites, not to altered receptor binding affinity, and was blocked by cycloheximide. PTH-stimulated adenylate cyclase was also enhanced by glucocorticoids, and a close correlation was observed between PTH binding and PTH-stimulated adenylate cyclase. However, hydrocortisone not only increased PTH binding but also enhanced the efficiency of postreceptor signaling: 5′-guanylimidodiphosphate [Gpp(NH)p]- and forskolin-stimulated adenylate cyclase activities were also increased. Thus, enhanced PTH stimulation of adenylate cyclase by glucocorticoids resulted from at least two effects—increased receptor availability and enhanced postreceptor efficiency of transmembranous signaling.
We have partially purified a tumour factor capable of stimulating both bone resorption in vitro and cAMP accumulation in osteoblastic ROS 17/2 cells from three human tumours associated with humoral hypercalcaemia of malignancy. Purification of tumour factor by sequential acid urea extraction, gel filtration and cation-exchange chromatography, reverse-phase high performance liquid chromatography followed by analytical isoelectric focussing provided a basic protein (pI greater than 9.3) with a molecular weight of approximately 13,000 as a major component of the final preparation which retained both the two bioactivities. Bone resorbing activity and cAMP-increasing activity in purified factor correlated with each other. cAMP-increasing activity of the factor was heat- and acid-stable, but sensitive to alkaline ambient pH. Treatment with trypsin destroyed cAMP-increasing activity of the factor. Synthetic parathyroid hormone (PTH) antagonist, human PTH-(3-34) completely inhibited the cAMP-increasing activity of the factor. The results suggest that this protein factor, having its effects on both osteoclastic and osteoblastic functions, may be involved in development of enhanced bone resorption in some patients with humoral hypercalcaemia of malignancy.
Capacitive heating is widely used in hyperthermic treatment of human malignancies. However, the pain on the body surface or thermoesthesia in the subcutaneous fatty layer may prevent an elevation of temperature in the tumors. Impedance matching is improved by a subtrap method entailing the application of two copper plates (10 x 850 x 0.06 mm) as a subtrap circuit to each of two capacitive electrodes. In a clinical trial the Tmax, Tave, Tmin for the subtrap method were all higher in comparison with those for the conventional technique (42.5 +/- 0.7 degrees C, 41.9 +/- 1.0 degrees C, 41.3 +/- 1.1 degrees C vs. 41.1 +/- 1.5 degrees C, 40.6 +/- 1.3 degrees C, 40.0 +/- 1.3 degrees C). Although the maximal radiofrequency (RF) power applied to patients was higher with the subtrap method (875 +/- 189 W vs. 763 +/- 200 W), the incidence of surface pain was reduced dramatically. It is concluded that the subtrap method substantially improves the RF capacitive heating of deep-seated tumors.
A method to improve the adhesion of a best-before date or expiration date on food packaging printed by ink-jet printer is employment of pretreatment, such as plasma irradiation. One of the candidates to be used in this process is the gliding arc which is a kind of atmospheric pressure plasma. In this paper, the effect of exit aperture size of gliding arc was investigated. The experimental parameters were short- and long-sides lengths of the rectangular aperture. Treated width and residual ratio of printed ink after rubbing test was measured. Maximum treatment width was about 40 mm and maximum residual ratio of printed ink was over 60%. The tendency of the effect of the aperture size was considered from downstream gas velocity and normal and high-speed observation of the plasma and its irradiation aspect. As a result, it was found that the arc column played dominant role for this surface treatment.
