Showing papers by "University of Colorado Denver published in 1971"
Journal Article•
TL;DR: Results indicate that disulfiram is an irreversible inhibitor of aldehyde dehydrogenase in vivo and can be blocked by cycloheximide.
Abstract: Aldehyde dehydrogenase in rat liver mitochondria and supernatant fluid has been assayed by following the rate of NADH production from NAD and aldehyde. Although it is known that disulfiram is a much more potent inhibitor in vitro of aldehyde dehydrogenase than diethyldithiocarbamate, the administration of either compound to rats brings about a decrease in enzyme activity in the livers of such animals. Very similar dose-response curves are obtained if it is assumed that diethyldithiocarbamate undergoes reoxidation to disulfiram in vivo . The decrease and return of activity of the supernatant and mitochondrial enzymes after disulfiram administration are identical in time course. The return of activity can be blocked by cycloheximide. These results indicate that disulfiram is an irreversible inhibitor of aldehyde dehydrogenase in vivo .
179 citations
TL;DR: It is found that healing in lamb fetuses prior to 120 days of gestation occurs without the presence of granulocytes, and the rapid healing cannot be explained by the germ-free environment.
164 citations
TL;DR: The present experiments showed that the thymus of a mouse given 2.5 mg of hydrocortisone acetate was as effective as a normalThymus in cooperating with bone marrow when transferred to irradiated syngeneic mice and stimulated with SRBC.
Abstract: Corticosteroids suppress the humoral antibody response of mice to sheep erythrocytes. This response depends on interactions between thymus-derived helper cells and bone marrow-derived antibody-forming cell precursors (AFC precursors). Previous experiments had shown that spleen cells (a mixture of thymus-derived and marrow-derived cells) were sensitive to corticosteroids while AFC precursors in the bone marrow were resistant. The present experiments showed that the thymus of a mouse given 2.5 mg of hydrocortisone acetate, although containing only about 5% of the number of cells of a normal thymus, was as effective as a normal thymus in cooperating with bone marrow when transferred to irradiated syngeneic mice and stimulated with SRBC. The proliferative response of thymus helper cells to SRBC was also resistant to hydrocortisone. In this context, the majority of thymic cells are in the cortex, are rapidly dividing, are sensitive to corticosteroids and are not iminunocompetent. A small number of thymic cells, probably located in the medulla, are resistant to corticosteroids, but are immunocompetent since they can serve as helper cells. The hydrocortisone-sensitive phase of the splenic response to SRBC was found to be the bone marrow-derived AFC precursor since spleens from hydrocortisone-treated donors had immunocompetence restored by normal bone marrow but not by normal thymus cells.
151 citations
TL;DR: Elevation of carboxykinase activity appears to be due to an increase in the rate of synthesis of this enzyme based on immunological evidence and cycloheximide inhibition of the response to both dexamethasone and DBcAMP.
131 citations
TL;DR: There has been evidence of clearance of body copper stores but without accumulation of copper in biopsy specimens of the transplanted liver after 6 and 17 months, which constitutes proof that Wilson's disease is an inborn error of hepatic metabolism.
103 citations
TL;DR: Ferreira et al. as discussed by the authors synthesized a bradykinin potentiating peptide from Bothrops jararaca venom, which had the same spectrum of pharmacological properties as previously reported for Bradykinin Potentiating Factor.
96 citations
TL;DR: Suggestions will be made for the application to the bone marrow problem of immunosuppressive regimens that have been evolved in the successful transplantation of whole organs such as the kidney, liver, and heart.
94 citations
TL;DR: Results are interpreted to indicate that hydrocortisone and cyclic AMP act at sequential sites n the synthesis of tyrosine transaminase, and the suggestion is made that cyclicAMP may act at a post-transcriptional evel in the case of both thetransaminase and carboxykinase.
80 citations
TL;DR: Nectin is heat labile and has an ultraviolet absorption spectrum typical of a protein and by the method of gel filtration through Sephadex, it is estimated that its molecular weight is 37,000.
68 citations
TL;DR: Under all conditions, PVO 2 was lower than in most other mammals, but always exceeded 20 mm Hg, reflecting the efficient mechanisms of O 2 extraction in the llama.
66 citations
TL;DR: A human enzyme, sulfatase A, was fractionated from liver and purified by electrofocusing and enhanced by the antibody under specified conditions, and could be used to purify the enzyme relatively simply and rapidly.
Journal Article•
TL;DR: The low concentration of this pterin cofactor in chromaffin tissue emphasizes its importance in the regulation of tyrosine hydroxylase activity and the potential susceptibility of the enzyme system to end product feedback inhibition by catecholamines.
Abstract: Tyrosine hydroxylase pterin cofactor has been isolated from bovine adrenal medulla tissue by means of column chromatography on Florisil and Dowex 50-H + columns, and paper chromatography in several solvent systems. The cofactor has been identified as a 6-substituted, unconjugated pteridine by permanganate oxidation to pterin-6-carboxylic acid. Its paper chromatographic behavior and fluorescence spectrum are identical with those of biopterin. The concentration of this pterin in bovine adrenal medulla tissue is estimated to be approximately 10 nmoles/g of tissue. The low concentration of this cofactor in chromaffin tissue emphasizes its importance in the regulation of tyrosine hydroxylase activity and the potential susceptibility of the enzyme system to end product feedback inhibition by catecholamines, which, according to Nagatsu, Levitt, and Udenfriend [ J. Biol. Chem. 239 , 2910 (l964)], appear to antagonize the action of the cofactor competitively in this hydroxylation reaction.
TL;DR: In an analysis of relationships among patient changes on the different variables over the first year of the program, improvement in objective signs, symptoms and psychological adjustment were all positively associated.
TL;DR: The induction of tyrosine aminotransferase in H-4-11-E hepatoma cells (a strain derived from H-35 Reuber hepatoma) in the presence of dibutyryl cyclic adenosine 3',5'-monophosphate (cyclic AMP) requires low concentrations of hydrocortisone.
TL;DR: Cyclophosphamide was substituted for azathioprine in one hepatic and five renal recipients who were suspected of having liver toxicity from azATHioprine 3 months to almost 8 years post-transplantation, and the evidence of liver injury subsided.
TL;DR: It is shown that the cell(s) in mouse spleen which can initiate graft versus host (GVH) reactions are resistant to the action of hydrocortisone.
Abstract: ALTHOUGH corticosteroids are usually considered to be lympholytic and immunosuppressive, some immunocompetent cells, presumably lymphoid, resist the actions of corticosteroids; for example, the graft versus host cell in chicken1 and mouse2 thymus, and the bone narrow antibody-forming cell precursor3. We have shown4 that the cell(s) in mouse spleen which can initiate graft versus host (GVH) reactions are resistant to the action of hydrocortisone. In these experiments, hydrocortisone was given to normal mice of parental strains. Two days later the surviving spleen cells (about 20%) were transferred to adult F1 hybrid recipients, where they showed unimpaired GVH responses as measured by splenomegaly. In these circumstances, the GVH initiator cell was exposed to hydrocortisone before coming into contact with antigen (mainly H2), and it was thus unlikely to be dividing rapidly, if at all5. Because there is evidence that corticosteroids have their greatest effects on rapidly dividing cells6,7 we have investigated the hydrocortisone sensitivity of GVH cells during antigenic stimulation, when thymus-derived cells are known to proliferate8,9.
TL;DR: The activator, which is not sedimented by centrifligation at 100,000 × g.
Abstract: Plasminogen activator was found to diffuse rapidly in large quantities into a warmed buffered saline solution retained in the vascular tree of the lower extremity of the human cadaver. The extractions, carried out 4 to 23 hours after death, yielded an average of 14.5 CTA (Committee on Thrombolytic Agents) units per ml. activator solution, with a total average yield of 9,621 units per leg. Correlations of activator yield with age, cause of death, and time elapsed after death before extraction were not observed. The activator, which is not sedimented by centrifligation at 100,000 × g., converts human plasminogen into plasmin at the zero-order reaction. It is rather stabile in the cold after ammonium sulfate factionation.
TL;DR: To characterize the minute amounts of enzyme activity which still remain in MLD, three aspects of sulfatase A have been studied: the amount of sulf atase A activity present; the kinetic parameters of the enzyme; and the effect on the enzyme activity of various compounds known to interact with enzyme proteins.
Abstract: METACHROMATIC leukodystrophy (MLD) is characterized by deficient activity of sulfatase A (arylsulfatase A; cerebroside sulfatase) and by a corresponding accumulation of cerebroside sulfate. The disease begins at different ages and evolves at different tempos. Late infantile, juvenile, adult, and variant forms occur. Each form tends to have subtly different clinical, neuropathological and chemical findings. How is one to explain the variation within this model disease? Are there any principles which, by extension, might give us a better understanding of the pathogenesis of other diseases? To begin to answer these questions we have started to characterize the minute amounts of enzyme activity which still remain in MLD. Three aspects of sulfatase A have been studied: (1) the amount of sulfatase A activity present; (2) the kinetic parameters of the enzyme; and (3) the effect on the enzyme activity of various compounds known to interact with enzyme proteins. The purposes of
TL;DR: There was a striking prolongation of the minimum time required for the induction of a wheal with a cold stimulus, and there was a significant reduction or elimination of cold sensitivity following natural exposure.
Abstract: We have been able to effectively treat cold-induced urticaria with cyproheptadine In 8 of 9 patients with primary acquired cold urticaria treated with this drug, there was a striking prolongation of the minimum time required for the induction of a wheal with a cold stimulus Concomitant with this change there was a significant reduction or elimination of cold sensitivity following natural exposure The one treatment failure occurred in a patient with an atypical familial form of cold urticaria The apparent effectiveness of cyproheptadine may be related to its broad antimediator activities
TL;DR: The photoreceptor of Amaroucium constellatum consists of three parts: lens cells, pigment cup, and retinal cells, which acts as a light shield, presumably allowing the tadpole to respond directionally to light.
Abstract: The photoreceptor of Amaroucium constellatum consists of three parts: lens cells, pigment cup, and retinal cells The three lens cells lie just beneath the epidermis and extend ventrally into the sensory vesicle A large part of their volume is occupied by a lens vesicle, a region bounded by mitochondria The function of the lens cells is unclear The pigment cup, a hollow hemisphere formed by the pigment cell, acts as a light shield, presumably allowing the tadpole to respond directionally to light No unusual morphological features of this cell have been noticed Each of the seven to ten photoreceptor cells sends a process through the pigment cup towards the lens cells A cilium at the tip of each process gives rise to membranous lamellae which are presumably photosensitive The base of each photoreceptor cell seems to send processes to the cerebral ganglion No synapses have been seen at the base of the photoreceptor cells The cerebral ganglion consists of a cellular cortex surrounding a medullary region of neuropil Two types of synapses, presumably chemical and electrical, are evident Four classes of vesicles are found in these structures
TL;DR: Both the Mg++-low salt and the Mn++-high salt-stimulated RNA polymerases showed an increased activity in the presence of N6, O2'-dibutyryl cyclic AMP.
TL;DR: The results show that the reaction is random with respect to order of substrate addition and that binary complex formation involving either cosubstrate or steroid may occur and that chemical transformation is not a rate-limiting step in the over-all reaction.
TL;DR: These data suggest that, at the 13th day of incubation, specialized mechanisms develop for the rapid distal transport of glycoprotein synthesized within the retinal ganglion cells to terminations in the optic tectum.
Abstract: The development of axonal transport in the optic nerve of the developing chick has been investigated. Following monocular injection of radioactive fucose and proline, the specific activity of protein from paired optic lobes was determined in chick embryos and new-hatched chicks. In addition, the magnitude of the acid soluble precursor pool within lobes was assayed. The specific activity of protein in the optic lobe contralateral to (and innervated by) the injected eye relative to that of protein within the corresponding ipsilateral lobe (not innervated by the injected eye) was used as an index of axonal flow. In embryonic chicks from 8–12 days of age, four hours after injection of 3H-fucase into a single eye, this ratio was somewhat above unity. In the 13-day incubated embryo the ratio rose abruptly to over 10, and remained high throughout the period studied (up to one day after hatch). No similar sharp rise was found for the corresponding ratio for acid soluble radioactivity which remained under 2 in all ages of chicks examined. Parallel experiments with 14C-proline resulted in a smaller and more gradual development of asymmetry of specific activity of protein from paired optic lobes.
These data suggest that, at the 13th day of incubation, specialized mechanisms develop for the rapid distal transport of glycoprotein synthesized within the retinal ganglion cells to terminations in the optic tectum. This phenomenon follows the major development of cerebral oxidative metabolism, but precedes the appearance of spontaneous or evoked potentials within the chick brain.
TL;DR: The results suggest that cyclic AMP in the brain may be involved in the regulation of the function of glial cells as well as neurons.
TL;DR: The antibody produced by immunizing rabbits with normal human sulfatase A did not restore any substantial activity to the MLD enzyme, or to the heat inactivated normal enzyme, so the enzyme protein is present in MLD but is functionally abnormal.
Abstract: A precipitating antibody was produced by immunizing rabbits with normal human sulfatase A. The rabbit antibody precipitated both the normal and the metachromatic leukodystrophy (MLD) sulfatase A from liver supernatant fractions. In the MLD samples, there was negligible sulfatase A activity in the resulting precipitin lines. Thus, the enzyme protein is present in MLD but is functionally abnormal. Ouchterlony double diffusion studies indicated that the sulfatase A protein in MLD was antigenically equivalent to the normal sulfatase A. The antibody does increase the activity of normal sulfatase A. It did not restore any substantial activity to the MLD enzyme, or to the heat inactivated normal enzyme. The existence of an enzyme protein in MLD is of interest. It raises the possibility that the activity of this protein might be increased by a therapeutic agent.
Journal Article•
TL;DR: Evidence is presented suggesting that radioactively labeled, inactive monoaminse oxidase may be taken up by lysosomes.
Abstract: Pargyline (N-methyl-N-2-propynylbenzylamine), an irreversible inhibitor of monoamine oxidase in vitro, was found to bind irreversibly to the enzyme in vivo. The apparent covalent nature of the latter binding was established by exhaustive washing and treatment of the protein with trichloracetic acid. The inhibitor was selective for monoamine oxidase in vivo as well as in vitro, which permitted the determination of the turnover rates of monoaminse oxidase in various subcellular fractions of rat liver. The half-life of mitochondrial monoamine oxidase was approximately 3.5 days, as determined by the rate of recovery of enzyme activity or by the decay of radioactivity after administration of sufficient 7-14C-pargyline to inhibit the enzyme completely. Similarly, the half-life of microsomal monoamine oxidase was found to be approximately 1 day. Evidence is presented suggesting that radioactively labeled, inactive monoaminse oxidase may be taken up by lysosomes. Cycloheximide completely prevented the recovery of monoamine oxidase activity in the microsomal fractions and markedly inhibited the rate of recovery of enzyme activity in the mitochondrial fractions.
TL;DR: The number of gene copies for 5S ribosomal ribonucleic acid (rRNA), relative to that for 16 and 23S rRNA, has been determined by deoxyribonucleo acid (DNA)-RNA hybridization for Escherichia coli and Bacillus megaterium.
Abstract: The number of gene copies for 5S ribosomal ribonucleic acid (rRNA), relative to that for 16 and 23S rRNA, has been determined by deoxyribonucleic acid (DNA)-RNA hybridization for Escherichia coli and Bacillus megaterium. In both cases, the number of 5S rRNA genes equals the number of 16 or 23S rRNA genes. Rapid procedures for preparing extremely highly purified DNA suitable for DNA-RNA hybridization experiments and chemically pure 5S rRNA are described.
TL;DR: The findings support the view that the membrane ATPase in S. faecalis functions in the active transport of K+ and that the organism responds adaptively to lack of K- during growth by producing additional ATPase.