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Sample records for aminopropionitrile

  1. Mechanisms for the inversion of chirality: Global reaction route mapping of stereochemical pathways in a probable chiral extraterrestrial molecule, 2-aminopropionitrile

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Ramanpreet; Vikas, E-mail: qlabspu@pu.ac.in, E-mail: qlabspu@yahoo.com [Quantum Chemistry Group, Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014 (India)

    2015-02-21

    2-Aminopropionitrile (APN), a probable candidate as a chiral astrophysical molecule, is a precursor to amino-acid alanine. Stereochemical pathways in 2-APN are explored using Global Reaction Route Mapping (GRRM) method employing high-level quantum-mechanical computations. Besides predicting the conventional mechanism for chiral inversion that proceeds through an achiral intermediate, a counterintuitive flipping mechanism is revealed for 2-APN through chiral intermediates explored using the GRRM. The feasibility of the proposed stereochemical pathways, in terms of the Gibbs free-energy change, is analyzed at the temperature conditions akin to the interstellar medium. Notably, the stereoinversion in 2-APN is observed to be more feasible than the dissociation of 2-APN and intermediates involved along the stereochemical pathways, and the flipping barrier is observed to be as low as 3.68 kJ/mol along one of the pathways. The pathways proposed for the inversion of chirality in 2-APN may provide significant insight into the extraterrestrial origin of life.

  2. The lysyl oxidase inhibitor (β-aminopropionitrile) reduces leptin profibrotic effects and ameliorates cardiovascular remodeling in diet-induced obesity in rats.

    Science.gov (United States)

    Martínez-Martínez, Ernesto; Rodríguez, Cristina; Galán, María; Miana, María; Jurado-López, Raquel; Bartolomé, María Visitación; Luaces, María; Islas, Fabián; Martínez-González, José; López-Andrés, Natalia; Cachofeiro, Victoria

    2016-03-01

    Lysyl oxidase (LOX) is an extracellular matrix (ECM)-modifying enzyme that has been involved in cardiovascular remodeling. We explore the impact of LOX inhibition in ECM alterations induced by obesity in the cardiovascular system. LOX is overexpressed in the heart and aorta from rats fed a high-fat diet (HFD). β-Aminopropionitrile (BAPN), an inhibitor of LOX activity, significantly attenuated the increase in body weight and cardiac hypertrophy observed in HFD rats. No significant differences were found in cardiac function or blood pressure among any group. However, HFD rats showed cardiac and vascular fibrosis and enhanced levels of superoxide anion (O2(-)), collagen I and transforming growth factor β (TGF-β) in heart and aorta and connective tissue growth factor (CTGF) in aorta, effects that were attenuated by LOX inhibition. Interestingly, BAPN also prevented the increase in circulating leptin levels detected in HFD fed animals. Leptin increased protein levels of collagen I, TGF-β and CTGF, Akt phosphorylation and O2(-) production in both cardiac myofibroblasts and vascular smooth muscle cells in culture, while LOX inhibition ameliorated these alterations. LOX knockdown also attenuated leptin-induced collagen I production in cardiovascular cells. Our findings indicate that LOX inhibition attenuates the fibrosis and the oxidative stress induced by a HFD on the cardiovascular system. The reduction of leptin levels by BAPN in vivo and the ability of this compound to inhibit leptin-induced profibrotic mediators and ROS production in cardiac and vascular cells suggest that interactions between leptin and LOX regulate downstream events responsible for myocardial and vascular fibrosis in obesity.

  3. The lathyrogenic effect of isonicotinic acid hydrazide (INAH) on the chick embryo and its reversal by pyridoxal.

    Science.gov (United States)

    LEVENE, C I

    1961-04-01

    When applied to the chorio-allantoic membrane of the chick embryo, isoniazid was shown to produce an increase in the fragility of the embryo and in the amount of collagen which was extractable from the bones with cold 1 M sodium chloride. The administration of pyridoxal reversed these phenomena almost completely. The effect of isoniazid differed from that of beta-aminopropionitrile in that the latter was of greater magnitude, and was not affected by pyridoxal; whereas beta-aminopropionitrile caused skeletal deformities, isoniazid even at 12 times the concentration produced no deformities. The aldehyde group of pyridoxal was shown to be necessary for its interaction with isoniazid.

  4. Biotechnology Conference: Drug Delivery and Drug Targeting Systems Held in London, United Kingdom on 14-15 December 1987

    Science.gov (United States)

    1988-07-10

    where the drug release is triggered or control- hydride copolymer) inside an albumin- urease system led by water or biological fluids and includes...topical delivery of beta- aminopropionitrile (BAPN), a collagen polymerization Drug Delivery inhibitor , for acute spinal cord injury in dogs...intercelluarjunctions. The magnitude of these properties peptidase inhibitors into the system to quench inactiva- may be used by pharmaceutical scientists to estimate

  5. ポリアクリルアミド ゲル ニヨル パパイン ノ コテイカ

    OpenAIRE

    "河邊,誠一郎/河邊,要太郎"; "カワベ,セイイチロウ/カワベ,ヨウタロウ/ウサミ,ショウジ"; "Kawabe,Seiichiro/Kawabe,Yohtaro/Usami,Shoji"

    1981-01-01

    "Papain was immobilized in crosslinked polyacrylamide gel by entrapment. The method is based on the polymerization of acrylamide in the presence of varying amount of N, N'-methylene bisacrylamide, 3-dimethyl aminopropionitrile and potassumpersulfate as crosslinking monomer, polymerization accelerator and initiator, in an aqueous medium containing the dissolved papain. It appeared that the only acrylamide as polymerization monomer decreased the activity of papain. Then, to protect papain again...

  6. Assaying embryotoxicity in the test tube: current limitations of the embryonic stem cell test (EST) challenging its applicability domain.

    Science.gov (United States)

    Riebeling, Christian; Hayess, Katrin; Peters, Annelieke K; Steemans, Margino; Spielmann, Horst; Luch, Andreas; Seiler, Andrea E M

    2012-05-01

    Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.

  7. Epidermal growth factor receptor inhibitor protects against abdominal aortic aneurysm in a mouse model.

    Science.gov (United States)

    Obama, Takashi; Tsuji, Toshiyuki; Kobayashi, Tomonori; Fukuda, Yamato; Takayanagi, Takehiko; Taro, Yoshinori; Kawai, Tatsuo; Forrester, Steven J; Elliott, Katherine J; Choi, Eric; Daugherty, Alan; Rizzo, Victor; Eguchi, Satoru

    2015-05-01

    Angiotensin II (Ang II) has been implicated in the development of abdominal aortic aneurysm (AAA). In vascular smooth muscle cells (VSMC), Ang II activates epidermal growth factor receptor (EGFR) mediating growth promotion. We hypothesized that inhibition of EGFR prevents Ang II-dependent AAA. C57BL/6 mice were co-treated with Ang II and β-aminopropionitrile (BAPN) to induce AAA with or without treatment with EGFR inhibitor, erlotinib. Without erlotinib, 64.3% of mice were dead due to aortic rupture. All surviving mice had AAA associated with EGFR activation. Erlotinib-treated mice did not die and developed far fewer AAA. The maximum diameters of abdominal aortas were significantly shorter with erlotinib treatment. In contrast, both erlotinib-treated and non-treated mice developed hypertension. The erlotinib treatment of abdominal aorta was associated with lack of EGFR activation, endoplasmic reticulum (ER) stress, oxidative stress, interleukin-6 induction and matrix deposition. EGFR activation in AAA was also observed in humans. In conclusion, EGFR inhibition appears to protect mice from AAA formation induced by Ang II plus BAPN. The mechanism seems to involve suppression of vascular EGFR and ER stress.

  8. Intracellular lysyl oxidase: Effect of a specific inhibitor on nuclear mass in proliferating cells

    Energy Technology Data Exchange (ETDEWEB)

    Saad, Fawzy A. [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Torres, Marie [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Wang, Hao [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Graham, Lila, E-mail: lilagraham@cs.com [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States)

    2010-06-11

    LOX, the principal enzyme involved in crosslinking of collagen, was the first of several lysyl oxidase isotypes to be characterized. Its active form was believed to be exclusively extracellular. Active LOX was later reported to be present in cell nuclei; its function there is unknown. LOX expression opposes the effect of mutationally activated Ras, which is present in about 30% of human cancers. The mechanism of LOX in countering the action of Ras is also unknown. In the present work, assessment of nuclear protein for possible effects of lysyl oxidase activity led to the discovery that proliferating cells dramatically increase their nuclear protein content when exposed to BAPN ({beta}-aminopropionitrile), a highly specific lysyl oxidase inhibitor that reportedly blocks LOX inhibition of Ras-induced oocyte maturation. In three cell types (PC12 cells, A7r5 smooth muscle cells, and NIH 3T3 fibroblasts), BAPN caused a 1.8-, 1.7-, and 2.1-fold increase in total nuclear protein per cell, respectively, affecting all major components in both nuclear matrix and chromatin fractions. Since nuclear size is correlated with proliferative status, enzyme activity restricting nuclear growth may be involved in the lysyl oxidase tumor suppressive effect. Evidence is also presented for the presence of apparent lysyl oxidase isotype(s) containing a highly conserved LOX active site sequence in the nuclei of PC12 cells, which do not manufacture extracellular lysyl oxidase substrates. Results reported here support the hypothesis that nuclear lysyl oxidase regulates nuclear growth, and thereby modulates cell proliferation.

  9. Collagen telopeptides (cross-linking sites) play a role in collagen gel lattice contraction

    Science.gov (United States)

    Woodley, D. T.; Yamauchi, M.; Wynn, K. C.; Mechanic, G.; Briggaman, R. A.

    1991-01-01

    Solubilized interstitial collagens will form a fibrillar, gel-like lattice when brought to physiologic conditions. In the presence of human dermal fibroblasts the collagen lattice will contract. The rate of contraction can be determined by computer-assisted planemetry. The mechanisms involved in contraction are as yet unknown. Using this system it was found that the rate of contraction was markedly decreased when collagen lacking telopeptides was substituted for native collagen. Histidinohydroxylysinonorleucine (HHL) is a major stable trifunctional collagen cross-link in mature skin that involves a carboxyl terminal, telopeptide site 16c, the sixteenth amino acid residue from the carboxy terminal of the telopeptide region of alpha 1 (I) in type I collagen. Little, if any, HHL was present in native, purified, reconstituted, soluble collagen fibrils from 1% acetic acid-extracted 2-year-old bovine skin. In contrast, HHL cross-links were present (0.22 moles of cross-link per mole of collagen) in lattices of the same collagen contracted by fibroblasts. However, rat tail tendon does not contain HHL cross-links, and collagen lattices made of rat tail tendon collagen are capable of contraction. This suggests that telopeptide sites, and not mature HHL cross-links per se, are essential for fibroblasts to contract collagen lattices. Beta-aminopropionitrile fumarate (BAPN), a potent lathyrogen that perturbs collagen cross-linking by inhibition of lysyl oxidase, also inhibited the rate of lattice cell contraction in lattices composed of native collagen. However, the concentrations of BAPN that were necessary to inhibit the contraction of collagen lattices also inhibited fibroblast growth suggestive of cellular toxicity. In accordance with other studies, we found no inhibition of the rate of lattice contraction when fibronectin-depleted serum was used. Electron microscopy of contracted gels revealed typical collagen fibers with a characteristic axial periodicity. The data

  10. Lathyrism-induced alterations in collagen cross-links influence the mechanical properties of bone material without affecting the mineral

    Science.gov (United States)

    Paschalis, E.P.; Tatakis, D.N.; Robins, S.; Fratzl, P.; Manjubala, I.; Zoehrer, R.; Gamsjaeger, S.; Buchinger, B.; Roschger, A.; Phipps, R.; Boskey, A.L.; Dall'Ara, E.; Varga, P.; Zysset, P.; Klaushofer, K.; Roschger, P.

    2011-01-01

    In the present study a rat animal model of lathyrism was employed to decipher whether anatomically confined alterations in collagen cross-links are sufficient to influence the mechanical properties of whole bone. Animal experiments were performed under an ethics committee approved protocol. Sixty-four female (47 day old) rats of equivalent weights were divided into four groups (16 per group): Controls were fed a semi-synthetic diet containing 0.6% calcium and 0.6% phosphorus for 2 or 4 weeks and β-APN treated animals were fed additionally with β-aminopropionitrile (0.1% dry weight). At the end of this period the rats in the four groups were sacrificed, and L2–L6 vertebra were collected. Collagen cross-links were determined by both biochemical and spectroscopic (Fourier transform infrared imaging (FTIRI)) analyses. Mineral content and distribution (BMDD) were determined by quantitative backscattered electron imaging (qBEI), and mineral maturity/crystallinity by FTIRI techniques. Micro-CT was used to describe the architectural properties. Mechanical performance of whole bone as well as of bone matrix material was tested by vertebral compression tests and by nano-indentation, respectively. The data of the present study indicate that β-APN treatment changed whole vertebra properties compared to non-treated rats, including collagen cross-links pattern, trabecular bone volume to tissue ratio and trabecular thickness, which were all decreased (p < 0.05). Further, compression tests revealed a significant negative impact of β-APN treatment on maximal force to failure and energy to failure, while stiffness was not influenced. Bone mineral density distribution (BMDD) was not altered either. At the material level, β-APN treated rats exhibited increased Pyd/Divalent cross-link ratios in areas confined to a newly formed bone. Moreover, nano-indentation experiments showed that the E-modulus and hardness were reduced only in newly formed bone areas under the influence