Lymphocytoid lines from persons with sex chromosome anomalies

Permanent lymphocytoid cell lines have been established from patients with the XYY and XXY chromosome constitutions. Large amounts of these and other cell lines with genetic defects can be provided for various studies.

Biphasic pattern of thymus regeneration after whole-body irradiation

Whole-body irradiation of mice with 300 or 400 R causes a precipitous fall in thymus weight, followed by an increase in the mitotic index and an almost complete restoration of thymus mass. This phase is followed by a secondary fall in thymus weight and gradual recovery. This secondary fall can be prevented by intravenous injection of bone marrow or shielding of the hind limbs during irradiation. The hypothesis is proposed that the thymus depends on the migration of cells from the bone marrow to the thymus for the maintenance of its cell population. Bone marrow cells with chromosome markers injected intravenously into normal or lightly irradiated (150 R) animals do not populate the host bone marrow to any significant degree. After whole-body irradiation with heavy doses (400 R), donor cells dominate the marrow. There may be a competition between dividing cells in the bone marrow which regulates proliferation of hemic cells. Bone marrow cells with marker chromosomes do not repopulate the thymus in irradiated animals until long after repopulating the bone marrow. It is possible that these cells have to pass through the marrow or the blood-marrow barrier to acquire characteristics needed for entering the thymus. After whole-body irradiation with 500 R or more, the first phase of regeneration of the thymus, represented by an increase in the mitotic index, does not occur to a significant degree. Apparently cells in the thymus capable of proliferation have been largely eliminated, and restoration of organ mass depends chiefly on seeding from other sources, probably the bone marrow. After whole-body irradiation with 200 R, only the first phase of thymus weight loss and regeneration takes place. Probably bone marrow injury is too small to interfere with the supply of cells repopulating the thymus.

Lipid composition of the subcellular elements, and mitochondrial respiration of the heart and liver in hypercholesterolemic rabbits

Rabbits were fed a diet containing 3% cholesterol for 2–6 months. Total cholesterol, cholesterol ester, phospholipids, and triglycerides were increased in the plasma. Total cholesterol and cholesterol ester were also increased in the heart mitochondria and supernatant, and liver mitochondria, microsomes, and supernatant, but triglycerides and phospholipids in all cell fractions studied remained within the normal ranges. The respiratory control ratio, P/O ratio, and oxygen consumption of the cardiac and hepatic mitochondria were not affected by the increase in cholesterol content. Possible mechanisms responsible for the altered lipid composition in the cells of rabbits on a high-cholesterol diet, as well as that for the unchanged mitochondrial respiratory function are discussed.

Continuous gas chromatography

Continuous gas chromatography has been achieved with a radialflow chromatographic channel free of packing and formed between two closely spaced (50 to 75 microns) disc surfaces (optically flat and solvent-coated) rotating at one-half or one revolution per second. This technique provides high capacity and immediate response (in a fraction of a second). Mixtures of hydrocarbon gases have been separated at flow rates of 6 to 30 cubic centimeters per minute with 100 to 150 cubic centimeters per minute of nitrogen carrier gas in a chromatographic channel only 39 millimeters long.