Isolation and properties of mitochondrial RNA from yeast.
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Centrifugation, Density Gradient↗
Biomedical subjects
S A Leon
Publications and source records attributed to S A Leon.
Avidity of antibodies in SLE: relation to severity of renal involvement.
The avidity of antibodies to DNA in the sera of 8 patients with SLE was determined by saturation analysis and Scatchard plots. Five of the patients had severe lupus nephritis; the other 3 had relatively mild or no kidney disease. The Scatchard plots revealed components with high relative avidity in the patients with severe nephritis (K values 4.4-10.4 X 10(5) M-1 for nDNA), compared with the patients who had mild or no kidney disease (K values 0.3-1.8 X 10(5) M-1 for nDNA). Avidity measurements may be helpful in the evaluation and treatment of patients with SLE.
Affinity Labels↗
Effects of hyperthermia on bone. I. Heating rate patterns induced by microwave irradiation in bone and muscle phantoms.
We describe the initial heating rate patterns generated by microwave irradiation of 915 MHz, with constant power output, in muscle-equivalent phantoms containing a freshly excised bone, and compared with those in phantoms consisting of muscle-equivalent gel only. At 1 cm depth the muscle was cooler in the centre of the field when bone was present underneath. Also, the orientation of the bone in the field had a pronounced effect on the heating rate profiles in the overlying muscle: when the long axis of the bone was parallel to E field, a hot area in the centre of the field was observed; after rotation of the applicator by 90 degrees so that the long axis of the bone was perpendicular to the E field, more homogeneous heating was obtained along most of the field. In contrast, the heating patterns obtained in the cortex of the bone at similar depth (1.3 cm) were not substantially influenced by its orientation in the field. Depending on field location, the heating rate of the cortical bone closest to the applicator was within 50-75% of the SAR in muscle at the same depth. We believe that these data may be useful for the extension of such measurements in vivo, to permit the effective application of hyperthermia, with or without radiation, in the treatment of bone lesions.
Bone Neoplasms↗
Effects of hyperthermia on bone. II. Heating of bone in vivo and stimulation of bone growth.
Previous studies in vitro have shown that it is possible to achieve comparable temperature distribution in bone and the adjacent soft tissues, under appropriate experimental conditions. The objective of the present work was to determine the effects of hyperthermia on bone in vivo. In order to obtain direct temperature measurements in bone, catheters were surgically installed on top of and inside the medullary cavity of the femur of normal rabbits. The thighs were irradiated with 915 MHz microwaves for 45 min, once or twice a week. The temperatures on and inside the bone were maintained between 42.5 and 44.0 degrees C; the resulting temperatures in the muscle were within 1.0 degrees C at depths equidistant from the applicator. After four to six treatments the femora were excised for histopathological examination. New trabecular bone was deposited around the catheters; most bone components including periosteum, osteoid, and fully calcified matrix could be seen. Large numbers of osteoblasts and osteoclasts lined the trabecular surfaces, and numerous cement lines were visible, running in all directions, indicating extensive bone deposition and remodelling. In contrast, control bones (catheters installed--no hyperthermia) showed much less ossification, with many areas of thin incomplete osteoid. Further, bones treated with hyperthermia only (no surgical trauma) showed no such changes. Thus, it appears that following an initial insult, hyperthermia promotes bone deposition.
Animals↗