Showing papers by "National Institutes of Health published in 1971"
TL;DR: The retardation coefficient is shown both empirically and theoretically to be a uniform function of molecular weight of protein-SDS complexes over specified ranges, providing a rationale for determining molecular weight from plots of the negative logarithm of relative mobility against molecular weight.
1,904 citations
TL;DR: A method of separation has been developed and applied to radioimmunoassays of insulin, parathyroid hormone, growth hormone and arginine vasopressin, which provides several advantages over the double-antibody precipitation method.
Abstract: Aqueous polyethylene glycol causes precipitation of antibody-bound peptide hormones labeled with radioactive iodine with little or no precipitation of free hormones. Based on this finding, a method of separation has been developed and applied to radioimmunoassays of insulin, parathyroid hormone, growth hormone and arginine vasopressin. The new method provides several advantages over the double-antibody precipitation method. It appears particularly valuable in immunoassays of substances of low molecular weight.
1,447 citations
TL;DR: The method has succeeded in producing specific antisera to the subunits of HCG and testosterone conjugates with one immunization of 20 to 100 μg of immunogen, and the potential of the method for producing specificantisers to glycoprotein and other hormones with limited amounts of purified material prompts this report.
Abstract: We have succeeded in producing specific antisera to the subunits of HCG and testosterone conjugates with one immunization of 20 to 100 μg of immunogen. The potential of the method for producing specific antisera to glycoprotein and other hormones with limited amounts of purified material prompts this report. Materials and Methods CR 100α and CR 100β, the subunits of HCG,. were prepared by Drs. R. E. Canfield and F. Morgan (1). Testosterone-3-(0-carboxymethy1) oxime was coupled to either bovine serum albumin (Armour) or keyhole limpet hemocyanin (Calbiochem) (2). Equal volumes of complete Freund's adjuvant, a 0.15 M NaCl solution of the immunogen and dried tubercle bacilli (2.5 mg/ml of total mixture) were homogenized for 5–10 minutes at increasing speeds to maximum setting in a Sorvall Omnimixer. Fur was shaved from the back and proximal limbs of 3 month old New Zealand white rabbits and the emulsion administered intradermally at 30–50 sites so that each animal received a total of 2 ml of the emulsion. At...
1,378 citations
TL;DR: Within a prospective study of 56,109 total births, 457 youngsters have been found to have congenital heart disease, and essentially equal numbers of blacks and whites had all types of coarctation of the aorta in line with the study population, which is 47% black and 53% white.
Abstract: Within a prospective study of 56,109 total births, 457 youngsters have been found to have congenital heart disease. The overall incidence is 8.14/1000 total births, 8.0/1000 for the Negro and 8.3/1...
1,144 citations
TL;DR: Evidence is presented to indicate a generalized role for the terminal sialic acid residues of circulating glycoproteins of desialylated plasma proteins inducers of gonadotropic hormones and follicle-stimulating hormone.
1,036 citations
TL;DR: The current practice of assessing the importance of blood pressure at all ages largely on the basis of diastolic pressure and the commonly held view concerning the innocuous nature of an elevated level of systolic pressure in the elderly requires reevaluation.
Abstract: A comparison of the contribution of systolic versus diastolic blood pressure to risk of coronary heart disease and the role of mean arterial pulse pressure and systolic lability have been examined prospectively in 5,127 men and women during 14 years of biennial follow-up studies. Similar gradients of risk of subsequent coronary heart disease were observed whether persons were classified by their systolic or diastolic pressure, and no “safe” or critical level could be identified. Assessment of the net effect of each, employing discriminant analysis, indicated a stronger association of systolic than diastolic pressure with risk of coronary heart disease. Neither the systolic and diastolic pressure measurements in combination nor the pulse pressure and the mean arterial pressure measurements alone discriminated better than the systolic measurement alone. Systolic lability did not predict incidence of coronary heart disease independently of the associated level of blood pressure. There was a trend of declining relative importance of diastolic and a corresponding increase in the importance of systolic pressure with advancing age. Only in those under 45 was diastolic pressure predominant. The level of casually obtained blood pressure was a good predictor of coronary heart disease. The current practice of assessing the importance of blood pressure at all ages largely on the basis of diastolic pressure and the commonly held view concerning the innocuous nature of an elevated level of systolic pressure in the elderly requires reevaluation.
840 citations
TL;DR: The correlation among a variety of physiological properties and the histochemical characteristics of muscle fibers belonging to single motor units in a mixed mammalian muscle is directly demonstrated.
Abstract: The correlation among a variety of physiological properties and the histochemical characteristics of muscle fibers belonging to single motor units in a mixed mammalian muscle is directly demonstrated. The population of motor units making up the cat gastrocnemius was classified into three nonoverlapping groups on the basis of a combination of physiological parameters. The muscle fibers belonging to motor units of each physiological type exhibited a distinctive histochemical profile, such that the three basic histochemical "fiber types" exactly matched the three physiologically defined groups. Within each individual motor unit, the muscle fibers were histochemically uniform.
761 citations
TL;DR: Relative mobility values for macromolecules in polyacrylamide gel electrophoresis at various gel concentrations are used to compute the retardation coefficient, KR, molecular radius, R, free mobility, M0, and valence, V.
690 citations
TL;DR: The treatment given here offers wide flexibility in dealing with cell surfaces in the languages of the cell physiologist, biochemist and physical chemist.
635 citations
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TL;DR: In this article, the authors gave a value of 188,000 for the molecular weight of a stable, catalytically inactive complex of 1 mole hydroxocobalamin and 1 mole of the apoenzyme complex of glycerol dehydrase.
Abstract: In spite of the considerable progress made in recent years toward the understanding of the chemistry and biological function of the cobalt-containing B(12) group of compounds, much of the information still is more descriptive than definitive in nature. In general terms, it is known that the free vitamin forms can function as methyl group carriers and that the 5'-deoxyadenosyl or coenzyme forms serve as hydrogen carriers; but the mechanism of these processes is not understood in detail. More systematic studies of the pure chemistry of these complex molecules containing a carbon-cobalt covalent bond are needed before the biochemist can interpret many of his observations on the enzyme-catalyzed reactions. Even in relatively simple solutions it is difficult to ascertain the state of oxidation of several of the vitamin forms, and these problems are compounded when the reactive thiol compounds and complex proteins of the biological systems also are present. For example, both vitamin B(12r) (the Co(2+) form) and corresponding analogs are known to disproportionate in solution to B(12s) (Co(1+)) and B(12a) (Co(3+)) under a variety of mild conditions (12, 57). This means that in the biological systems it is exceedingly difficult to ascertain the chemical nature of many B(12) intermediates and reaction products. The role of the protein moiety of the various B(12)-linked enzymes in the catalytic processes is little known as is, also, the mode of binding of the B(12) derivative to the protein. These types of questions perhaps can be answered eventually by the crystallographers, whose art is becoming increasingly sophisticated. Note added after preparation of manuscript. In contrast to the values given in Table 4 for the molecular weights of the two dissimilar protein moieties of glycerol dehydrase, a recent report (57a), gives a value of 188,000 for the molecular weight of a stable, catalytically inactive complex of 1 mole of hydroxocobalamin and 1 mole of the apoenzyme complex of glycerol dehydrase. The latter is presumed to contain one equivalent of each of the two dissimilar protein subunits. The original estimate of 240,000 as the molecular weight of the unstable sulfhydryl protein moiety (39) was undoubtedly made on partially aggregated material.
556 citations
TL;DR: 125I-insulin binding to liver membranes was inhibited by unlabeled insulin at physiological concentrations, and monoiodoinsulin prepared by this method was bound to isolated fat cells and to purified plasma membranes from liver.
TL;DR: The sequences of the 35 and 36 amino-terminal amino acids of two purified amyloid fibril proteins have been determined and indicate that these two proteins are derived from homogeneous immunoglobulin light chains of variable region subgroup VκI.
Abstract: The sequences of the 35 and 36 amino-terminal amino acids of two purified amyloid fibril proteins have been determined. Results indicate that these two proteins are derived from homogeneous immunoglobulin light chains of variable region subgroup V(kappaI). The relation between amyloidosis and immunoglobulins is thus more firmly established.
TL;DR: Previous molecular weights proposed for the human erythrocyte membrane glycoprotein utilizing SDS gel electrophoresis are probably incorrect and a new value of 55,000 is proposed based on corrected SDS-gel data.
TL;DR: Each membrane is found to have an identifiable glycoprotein subunit pattern composed of at least 6 to 11 different sized subunits, and most of the staining intensity is present in one to three subunits.
TL;DR: Various levels of structural organization in collagen are described by means of a distinctive molecular conformation arising from special regularities in its amino acid sequence and their chemical basis.
Abstract: Publisher Summary Collagen is the major protein constituent of a wide range of vertebrate and invertebrate species and it occurs in diverse tissues such as bone, skin, tendon, cornea, and basement membrane. It has been implicated in morphogenesis and various complex regulatory mechanisms during growth and wound healing that the role of collagen in mature tissue is primarily structural. It fulfills this function by means of a distinctive molecular conformation arising from special regularities in its amino acid sequence. This chapter describes these various levels of structural organization in collagen and their chemical basis. The triple-stranded, coiled-coil structure of collagen as determined by X-ray diffraction is widely accepted. Its rodlike shape and dimensions of about 3000 X 15 A are also well established. However, the physical evidence says that in cross section the collagen molecule must contain three polypeptide chains. It does not indicate whether the chains are parallel or antiparallel, whether there are many short ones or perhaps one long chain folded back on it twice, or whether they are identical or nonidentical.
TL;DR: The first in a now-classic series of five articles in which Rodbell concluded that GTP was likely the active biological factor in separating glucagon, a hormone that can act to increase blood glucose levels, from the cell's receptor, had important implications for the treatment of various disorders and diseases.
TL;DR: Evidence is presented to establish the identity of the radioactive derivative as 5-acetamido-3, 5-dideoxy-l-arabino-2-heptulosonic acid and to indicate it as the sole site of tritium incorporation in the carbohydrate chain.
TL;DR: A pharmacokinetic model is presented to predict the detailed distribution and excretion of methotrexate in several mammalian species over a wide range of doses.
TL;DR: Plasma membranes prepared from rat livers treated with digitonin or phospholipase A under conditions which result in substantial loss of glucagon- Stimulated adenyl cyclase activity but no loss of fluoride-stimulated activity are thought to reflect extensive modification of the structures responsible for hormone sensitivity without destruction of the catalytic component of the adeny cyclase system.
TL;DR: The simplicity of the present assay permits the use of epoxide hydrase a a marker enzyme for microsomal membranes in hepatic microsomes increases during maturation of rats and following pretreatment of rats with phenobarbital or 3-methylcholanthrene.
TL;DR: It is concluded that the previous reports that tyrosine hydroxylase is stimulated by Fe2+ can be explained by the known ability ofFe2+ to decompose H2O2.
TL;DR: The data indicate the existence of at least two forms of benzo[ a ]pyrene hydroxylating enzyme systems in rat tissues which can be differentially induced in vivo by administration of phenobarbital or methylcholanthrene.
TL;DR: Six clonal lines of human choriocarcinoma have been established from a tumor previously adapted to passage in the hamster cheek pouch, providing systems for the examination of many aspects of placental physiology and biology.
Abstract: Six clonal lines of human choriocarcinoma have been established from a tumor previously adapted to passage in the hamster cheek pouch. All clones have continued to produce chorionic gonadotropin (CG) for over 2 yr. The rates of hormone secretion and growth differed among the clonal lines. In one clone, cell count and CG production showed log increases and plateau phases, but the log phase of CG synthesis occurred as the rate of cell replication slowed. Accordingly, CG production per cell increased progressively with time. These functional cell lines provide systems for the examination of many aspects of placental physiology and biology.
TL;DR: The genetic locus described appears of major significance in the biology of murine leukemia and has no effect on growth of certain laboratory-passaged leukemia viruses which propagate equally well on embryo cells of all mouse strains, F1, and backcross hybrids.
Abstract: Previous studies have indicated that all naturally occurring murine leukemia viruses propagate significantly more efficiently on embryo cells of either NIH Swiss or BALB/c mice. Studies of the plaquing efficiency of representative viruses on embryo cells of various inbred and hybrid mice indicate that the pattern of sensitivity of the cells is genetically determined. All of 23 strains tested were found to resemble either NIH Swiss (N-type) or BALB/c (B-type) with respect to plaquing efficiency of these viruses. Virus growth on embryo cells derived from (N-type x B-type)F1 hybrids indicated dominance of resistance to both types of viruses. Backcross hybrid studies indicated that a single locus is the primary determinant of the host-range patterns observed. This locus has no effect on growth of certain laboratory-passaged leukemia viruses which propagate equally well on embryo cells of all mouse strains, F1, and backcross hybrids. Though other genetic and nongenetic factors influence viral growth or expression in vitro and in vivo, the genetic locus described appears of major significance in the biology of murine leukemia.
TL;DR: Prenatal administration of 2,4,5-T did not affect the postnatal growth and development of the CD rat, and when these compounds were administered in combination, the activity was not potentiated at the doses employed.
TL;DR: Evidence is presented to identify plasma membranes of liver as the major locus of binding for circulating glycoproteins and the binding process involves a dual role for sialic acid in that its presence on the membranes is essential, whereas its existence on the glycoprotein is incompatible with binding.
TL;DR: It has become increasingly evident that most of the oxidative reactions are catalyzed by enzyme systems in liver endoplasmic reticulum, which is disrupted by homogenization to form microsomes, and the diversity of the reactions catalyzing by these enzymes is virtually unique in biochemistry.
Abstract: The biological fate of a drug depends on a host of factors, including those which determine its volume of distribution, its excretion into air, bile, and urine, and its metabolism by various enzyme systems in the body. A number of foreign compounds closely resemble normal body substances and thus can interact with rather specific transport systems, carrier proteins, and enzymes. Analogues of purines, pyrimidines, fatty acids, steroids, amino acids, and biogenic amines belong to this group. In general, however, foreign compounds have no endogenous counterpart and are metabolized by nonspecific enzymes and transported by either passive diffusion or nonspecific transport systems. I t is now known that most foreign compounds are metabolized along a diversity of chemical pathways leading to a wide variety of urinary metabolites. Several years ago, Dr. R. T. Williams' pointed out that foreign compounds are usually converted into metabolites of ever increasing polarity until finally they can be readily excreted by the kidney. This process is usually carried out in two general phases (TABLE 1): (1) Polar groups are introduced into nonpolar compounds by oxidation, reduction, and hydrolysis reactions, or alkyl groups are removed to uncover potential polar groups; (2) the polar group is conjugated with glucuronate, sulfate, glycine, glutamine, acetate, or methyl groups. The metabolites formed by these various reactions have different volumes of distribution and are excreted by the kidney at different rates. Thus, the relative amounts of metabolites in urine provide only indirect and frequently fallacious estimates of their concentrations in body tissues and blood plasma. For this reason, many studies of drug metabolism include the isolation of metabolites from tissues. Even in these studies, however, the relative importance and location of the enzymes operative in drug metabolism in different tissues are obscure because the metabolites may be located in tissues other than those in which they are formed. Studies in uitro have revealed that liver is the main site for the metabolism of foreign compounds by nonspecific enzymes, although metabolism may also occur to varying extents in other tissues and bacterial flora of the gastrointestinal tract. During the past several years, it has become increasingly evident that most of the oxidative reactions are catalyzed by enzyme systems in liver endoplasmic reticulum, which is disrupted by homogenization to form microsomes. Indeed, the diversity of the reactions catalyzed by these enzymes is virtually unique in biochemistry (TABLE 2).
TL;DR: The relation between amyloidosis and immunoglobulins is thus more firmly established and a pathogenetic mechanism for amyloids fibril formation is suggested.
Abstract: "Amyloid" fibrils have been created from some human Bence Jones proteins by proteolytic digestion under physiologic conditions. These fibrils with an antiparallel, β-pleated sheet conformation consist of only a portion of the variable region of the immunoglobulin light polypeptide chain and share the physical properties of amyloid fibrils. The relation between amyloidosis and immunoglobulins is thus more firmly established and a pathogenetic mechanism for amyloid fibril formation is suggested.