Defective spectrin dimer-dimer association in a family with transfusion dependent homozygous hereditary elliptocytosis.

Red cell membrane proteins have been examined in a family in which three children have severe transfusion-dependent homozygous hereditary elliptocytosis. The membranes in all three show a considerable excess of spectrin dimers over tetramers in spectrin extracts. The red cell membranes of their parents with heterozygous hereditary elliptocytosis show a lesser but significant increase in spectrin dimers.

Tumoral calcinosis.

Tumoral calcinosis is an uncommon, usually solitary, tumour-like mass characterized by soft tissue calcification for no apparent reason. Nearly all cases have occurred in negroes, including 2 previously recorded in this country. We report 7 cases seen over a period of 3 years in English caucasian patients and suggest that the condition is not rare but goes unrecognized under a variety of guises.

Inhibition of protein breakdown by epidermal growth factor in IMR90 human fibroblasts and other mammalian cell lines.

1. Epidermal growth factor (EGF) inhibits intracellular protein breakdown in IMR90 human fibroblasts and other cell lines having EGF receptors. 2.

Effects of microbial proteinase inhibitors on the degradation of endogenous and internalized proteins by rat yolk sacs.

1. The effects of leupeptin and other microbial proteinase inhibitors were measured in rat yolk sacs on the uptake and degradation of formaldehyde-denatured 125I-labelled bovine serum albumin as well as on the degradation of 3H-labelled endogenous protein. 2.

Regulation of intracellular protein degradation by insulin and growth factors.

Protein breakdown in many cell lines is inhibited by growth factors. The response is specific, rapid and additive only at suboptimal concentrations. Transformed cells are typically more sensitive to growth factors than nontransformed cells while the effectiveness of growth factors in human fibroblasts is diminished with senescence.

Insulin inhibition of protein degradation in cell monolayers.

Protein degradation has been measured in confluent monolayers of eleven lines of contact-inhibited cells and ten transformed lines as the rate of release of trichloroacetic acid-soluble radioactivity after prelabeling cell protein with [3H]leucine. Insulin, at contrations from 10(-12) M to 10(-6) M, has been added at the beginning of the 4-hour degradation period to detect selective effects of this hormone as an inhibitor of the inducible proteolysis occurring in serum-free medium. In addition insulin binding measurements have been performed on selected cell lines in an attempt to relate receptor properties to insulin action.

Effects of weak bases on the degradation of endogenous and exogenous proteins by rat yolk sacs.

In rat yolk sacs incubated in vitro, the rates of degradation of endogenous [3H]leucine-labelled proteins and of pinocytically ingested 125I-labelled bovine serum albumin were both decreased in the presence of either ammonium, methylammonium or ethylammonium ions (0-20 mM) or much lower concentrations of chloroquine (0-500 microM). These effects were also accompanied by an inhibition of pinocytosis, as measured by the rate of uptake of 125I-labelled polyvinylpyrrolidone, and by a fall in the [ATP]/[ADP] ratio within the tissue. Re-incubation in inhibitor-free medium of yolk sacs previously exposed to a weak base restored pinocytic and proteolytic capacities, except for tissues exposed to chloroquine at concentrations above 0.

Inactivation of cytosol enzymes by a liver membrane protein.

Non-proteolytic inactivation reactions have been suggested to play an important role in determining the relative rates of enzyme degradation within cells. An inactivation factor is present at high specific activity in hepatocyte plasma membrane which inactivates cytosol enzymes at rates roughly proportional to their rates of degradation in vivo. This factor has been purified about 100-fold and has similar catalytic selectivity to the crude factor.

Effects of amino acid analogues on protein synthesis and degradation in isolated cells.

1. Naturally-occurring and synthetic analogues of phenylalanine, tyrosine, histidine, arginine, proline, tryptophan and the sulphur amino acids have beeen tested in rat reticulocytes and in the Reuber H35 hepatoma for effects on protein synthesis and protein degradation and on the heat lability of phosphoenolpyruvate carboxykinase (EC 4.1.

Real-time, very-long-baseline interferometry based on the use of a communications satellite.

The Hermes satellite, a joint Canadian-American program, has been used to provide a communication channel between radio telescopes in West Virginia and Ontario, for very-long-baseline interferometry (VLBI). This system makes possible instantaneous correlation of the data as well as a sensitivity substantially better than that of earlier VLBI systems, by virtue of a broader observational bandwidth. With the use of a geostationary communications satellite it is possible to eliminate the tape recorders and the most troublesome part of the postobservational data processing.

Attempts to relate enzyme inactivation to degradation in vivo.

Inactivation of liver cytosol proteins has been measured in vitro in the presence of various membranes and disulphides. Inactivation rates correlate with the known degradation rate constants of the enzymes in the intact liver. More extensive studies were carried out with glucose-6-phosphate dehydrogenase (G6PD) and phosphoenolpyruvate carboxykinase (PEPCK) using either cytosol as a source of these enzymes or alternatively highly purified preparations of each enzyme.

Selective control of the degradation of normal and aberrant proteins in Reuber H35 hepatoma cells.

1. Rates of degradation of normal and abnormal protein were measured in hepatoma cells after labelling first for 16h with [14C]leucine plus L-arginine and then for 3h with [3H]-leucine plus the arginine analogue, L-canavanine. 2.

Increased degradation rates of protein synthesized in hepatoma cells in the presence of amino acid analogues.

1. Reuber H35 hepatoma cells incorporate the arginine analogue canavanine into cell protein when arginine is omitted from the incubation medium. 2.

Properties of phosphoenolpyruvate carboxykinase (guanosine triphosphate) synthesized in hepatoma cells in the presence of amino acid analogues.

Phosphoenolpyruvate carboxykinase (GTP) was induced by a combination of dibutyryl cyclic AMP, theophyline and dexamethasone in Reuber H35 hepatoma cells under conditions where an amino acid in the medium was replaced by an appropriate analogue. 2. With canavanine replacing arginine or with 5-fluorotryptophan or 6-fluorotryptophan replacing tryptophan the induced enzyme had a lower catalytic activity-relative to antibody reactivity.

Production and utilization of acetate in mammals.

1. In an attempt to define the importance of acetate as a metabolic precursor, the activities of acetyl-CoA synthetase (EC 6.2.

Galactic water vapor emission: further observations of variability.

Recent observations of the 1.35-centimeter line emission of water vapor from galactic sources show short-term variability in the spectra of several sources. Two additional sources, Cygnus 1 and NGC 6334N, have been observed, and the spectra of W49 and VY Canis Majoris were measured over a wider range of radial velocity.

Spectra, Variability, Size, and Polarization of H2O Microwave Emission Sources in the Galaxy.

Radio spectral line radiation of water molecules at a wavelength of 1.35 centimeters has been measured from eight sources in the galaxy. The sources are less than I arc minute in diameter, have extremely high brightness temperatures, and show many spectral features.