Erythropoietin: isolation by affinity chromatography with lectin-agarose derivatives.

Affinity chromatography using agarose-bound lectins was used to isolate erythropoietin from crude preparations of sheep plasma and human urinary erythropoietin. On the basis of previous estimates of the sugar content of the hormone, six lectins (wheat germ agglutinin, phytohemagglutinin, Ricinus communis 120, soybean agglutinin, concanavalin A, and limulin) were chosen for study. Only wheat germ agglutinin-agarose and phytohemagglutinin-agarose derivatives had significant affinity for erythropoietin.

Cardiac cellular responses to altered nutrition in the neonatal rat.

Rats reared in litters of 18, 12, and 6 to determine whether preweanling nutritional state would alter rates of cardiac cell division, weighed 31.7, 39.1, 48.

Complicated colobomatous microphthalmos in the BW rat: a new form of inherited retinal degeneration.

A new model of inherited retinal degeneration has been found in the rat. It is inherited in association with a number of other ocular defects, including microphthalmos, coloboma, retinal dysplasia, optic nerve hypoplasia and/or aplasia, as well as medullation of the nerve fiber layer of the retina. Together, these abnormalities constitute a condition referred to as complicated colobomatous microphthalmos.

Topographic separation of adenylate cyclase and hormone receptors in the plasma membrane of toad erythrocyte ghosts.

Brief sonication of whole erythrocyte plasma membranes (ghosts) from toads at 4 degrees does not inactivate adenylate cyclase [ATP pyrophosphate-lyase (cyclizing); EC 4.6.1.

Normal amino acid uptake by cultured human fibroblasts does not require gamma-glutamyl transpeptidase.

The uptake kinetics for four amino acids (cystine, glutamine, methionine, and alanine) which are among the best gamma-glutamyl acceptors have been determined for normal human fibroblasts and for a cell line containing undetectable quantities (< 0.5% normal mean) of gamma-glutamyl transpeptidase activity. Apparent Km and V(max) for uptake for each of the four amino acids were normal in the mutant fibroblasts.

Effects of hypoxia on cardiac growth in neonatal rat.

To determine whether low oxygen environments enhance cardiac cell division in the neonatal period, newborn rat pups were reared for 21 days in 12-15% oxygen. Left ventricle and right ventricle weights were 30 and 180% greater than controls matched for body weight (P less than 0.001) as were left ventricle/body weight ratios (3.

Ankylosing spondylitis with complete heart block.

A patient with complete heart block due to ankylosing spondylitis exhibited an unusually brisk increase in ventricular rate with exercise. Despite broad ventricular (QRS) complexes, His bundle electrograms demonstrated a His deflection before each QRS complex and thus established the level of atrioventricular (A-V) block to be proximal to or localized to the His bundle. A junctional pacemaker accounted for the brisk response to exercise, atropine, or isoproteronol.

Impaired parasympathetic responses in patients after myocardial infarction.

To assess whether vagal and sympathetic responses are impaired 3 months after myocardial infarction, 27 patients, 15 age-matched control subjects and 13 young normal subjects underwent physiologic stress tests. In patients, facial immersion in water at 25 degrees and 0 degrees C provoked less slowing of heart rate than in age-matched control subjects. Young normal persons responded with the greatest reduction in heart rate.

Surface morphology of lens fibers from eyes of normal and microphthalmic (Browman) rats.

The surface features of cortical fibers from lenses of normal adult rats and microphthalmic rats of the Browman strain have been studied by scanning electron microscopy. In the normal lenses, superficial cortical fibers follow a straight course from inner to outer pole whereas the deeper cortical fibers, while straight near the poles, pursue an undulating or zig-zag course at and near the equator. Almost all of the fibers are hexagonal in cross section and all fibers throughout their entire length are bound by interdigitating processes at each corner of the hexagon to corners of two adjacent fibers.

Ultrastructural study of lesions induced in rabbit cornea by Herpes Simplex virus types 1 and 2.

Herpes simplex virus types 1 and 2 were used to infect rabbit corneas (without abrasion), and the resulting lesions were compared by light and electron microscopy. The type 1-induced lesion developed more quickly; the infected epithelial cells underwent a progression of defined morphological changes leading to organelle destruction, cell rounding, and death. Virus particles were abundant in the nuclei and cytoplasm of all types of cell in the epithelium, in intercellular spaces, and on the basement membrane.

Structure and function of cholera toxin and hormone receptors.

The enterotoxin from Vibrio cholerae is a protein of 100,000 mol wt which stimulates adenylate cyclase activity ubiquitously. The binding of biologically active 125I-labeled choleragen to cell membranes is of extraordinary affinity and specificity. The binding may be restricted to membrane-bound ganglioside GM1.

Lesions produced by human herpesviruses 1 and 2. Morphologic features in rabbit corneal epithelium.

The morphologic features of corneal lesions produced in rabbits by human herpesviruses, types 1 and 2 (HH1 and HH2), were studied using light and electron microscopic techniques. Also, healing lesions produced by the HH1 virus and treated by idoxuridine were similarly investigated. Scanning electron micrographs showed that although the morphology of HH1 and HH2 lesions was similar in most respects.

Insulin: interaction with membrane receprots and relationship to cyclic purine nucleotides and cell growth.

Insulin action is discussed with emphasis on events that occur at the plasma membrane. A summary is presented of previous studies which indicate that the insulin receptor of fat and liver cells is a large glycoprotein, partially buried in the outer surface of the plasma membrane, with a high (K-D approximately 10-10 M) and specific affinity for insulin. The participation of membrane phospholipids in the binding of insulin and the role of sialic acid residues in the transmission of the insulin binding signal are discussed.

Insulin and epidermal growth factor. Human fibroblast receptors related to deoxyribonucleic acid synthesis and amino acid uptake.

Receptors for insulin and epidermal growth factor (EGF) have been studied in confluent cultured intact human fibroblast monolayers. 125-I-EGF binds specifically to fibroblast monolayers. Half-maximal binding is observed at 4 times 10 minus 10 M EGF; at saturation of binding approximately 4 times 10-4 molecules of EGF are bound per cell.