617 research outputs found
New dysplasia or achondrogenesis type 1 B? The importance of histology and molecular biology in delineating skeletal dysplasias.
No full textThree novel mutations in the ANK membrane protein cause craniometaphyseal dysplasia with variable conductive hearing loss
No full textCraniometaphyseal dysplasia (CMD) is a rare, sclerosing skeletal disorder caused by mutations in ANKH, which encodes a putative pyrophosphate transporting membrane protein. Six distinct ANKH mutations have been described to date. We report here on three novel mutations in simplex patients with CMD. The c.1015T>C (p.Cys339Arg) mutation found in Patient A was associated with congenital facial palsy, early-onset conductive hearing loss, and a generalized undermodeling of the long bones. The c.1172T>C (p.Leu391Pro) mutation in Patient B was associated with facial palsy, progressive conductive hearing loss, and generalized undermodeling of tubular bones. A milder phenotype without cranial nerve affection was observed in Patient C, associated with a c.1001T>G (p.Leu334Arg) mutation. All affected residues lie in evolutionarily conserved sequence blocks. These additional cases and the associated mutations contribute to an improved appreciation of the variability of this rare skeletal dysplasia. (c) 2010 Wiley-Liss, Inc
A broad spectrum of clinical presentations in congenital disorders of glycosylation I: a series of 26 cases.
No full textOwing to the remarkable clinical variability of CDG, this novel disease probably remains largely underdiagnosed. The successful treatment of CDG Ib patients with oral mannose emphasises the paramount importance of early diagnosis of PMI deficiency
Effect of substituents on the thermal decomposition of diazirines: Experimental and computational studies
No full textThe thermal decomposition of phenylehlorodiazirine (1), phenyl-n-butyldiazirine (2), and 2-adamantane-2,3'-[3H] diazirine (3) has been studied in solution in the presence Of C-60. The C-60 probe technique indicates that in the decomposition diazirine 1 yielded exclusively phenylchlorocarbene, diazirine 2 yielded mainly a diazo intermediate, and diazirine 3 yielded a mixture of carbene and diazo compound. In the case of diazirine 2, 13% of (E)-1-phenyl-1-pentene resulted from the direct thermal rearrangement of diazirine without the participation of a carbene. As well, the thermal decomposition of these diazirines has been studied theoretically with ab initio and density functional methods. The experimental results are broadly in agreement with the theoretical predictions. The calculations further indicate that the rebound reaction between carbene and molecular nitrogen leading to the formation of a diazo intermediate is an important reaction in the gas-phase decomposition of diazirine.PT: J; CR: AKASAKA T, 2000, J AM CHEM SOC, V122, P7134 AMRICH MJ, 1964, J AM CHEM SOC, V86, P292 BECKE AD, 1988, PHYS REV A, V38, P3098 BECKE AD, 1993, J CHEM PHYS, V98, P5648 BONNEAU R, 1998, ADV CARBENE CHEM, V2, P1 BONNEAU R, 1998, J PHOTOCH PHOTOBIO A, V116, P9 CELEBI S, 1993, J AM CHEM SOC, V115, P8613 DIEDERICH F, 1994, CHEM SOC REV, P243 DIEDERICH F, 1994, NATURE, V369, P199 FIGUERA JM, 1976, AN QUIM, V72, P737 FIGUERA JM, 1978, J CHEM SOC F1, V74, P809 FREY HM, 1962, P CHEM SOC, P79 FREY HM, 1963, J CHEM SOC, P3514 FREY HM, 1964, J CHEM SOC, P4700 FREY HM, 1965, J CHEM SOC, P1700 FREY HM, 1965, J CHEM SOC, P3101 FREY HM, 1966, ADV PHOTOCHEM, V4, P225 FRISCH MJ, 2001, GAUSSIAN 98 REVISION GONZALEZ R, 1995, J ORG CHEM, V60, P2618 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 HEHRE WJ, 1972, J CHEM PHYS, V56, P2257 HIRAO K, 1992, CHEM PHYS LETT, V190, P374 HIRAO K, 1992, CHEM PHYS LETT, V196, P397 HIRAO K, 1992, INT J QUANTUM CHEM S, V26, P517 HIRAO K, 1993, CHEM PHYS LETT, V201, P59 HIRSCH A, 1993, ANGEW CHEM INT EDIT, V32, P1138 HIRSCH A, 1994, CHEM FULLERENES HIRSCH A, 1999, FULLERENES RELATED S ISAEV SD, 1973, ZH ORG KHIM+, V9, P724 JENNINGS BM, 1976, J AM CHEM SOC, V98, P6416 LAUFER AH, 1971, J AM CHEM SOC, V93, P4137 LEE C, 1988, PHYS REV B, V37, P785 LIU M, 1987, CHEM DIAZIRINES LIU MTH, 1972, CAN J CHEM, V50, P3009 LIU MTH, 1972, J PHYS CHEM-US, V76, P797 LIU MTH, 1977, CAN J CHEM, V55, P3596 LIU MTH, 1982, CHEM SOC REV, V11, P127 MERRER DC, 2001, ADV CARBENE CHEM, V3, P53 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 MOORE CB, 1964, J CHEM PHYS, V41, P3504 NAKANO H, 1993, J CHEM PHYS, V99, P7983 NAKANO H, 1995, MR2D VER 2 PAULSEN SR, 1960, ANGEW CHEM, V72, P781 PLATZ MS, 1998, ADV CARBENE CHEM, V2, P133 PLATZ MS, 2002, CARBENE CHEM, P27 PLATZ MS, 2002, CARBENE CHEM, P44 ROOS BO, 1987, ADV CHEM PHYS, V69, P399 SCHMIDT MW, 1993, J COMPUT CHEM, V14, P1347 SCHMITZ E, 1961, TETRAHEDRON LETT, P612 SHILOV AE, 1968, TETRAHEDRON LETT, P4177 SMITH AB, 1993, J AM CHEM SOC, V115, P5829 STEVENS IDR, 1990, J CHEM SOC P2, P661 SUZUKI T, 1991, SCIENCE, V254, P1186 SUZUKI T, 1992, J AM CHEM SOC, V114, P7301 TAYLOR R, 1993, NATURE, V363, P685 TAYLOR R, 1996, CHEM FULLERENS WAKAHARA T, 2002, J AM CHEM SOC, V124, P9465; NR: 57; TC: 5; J9: J ORG CHEM; PG: 8; GA: 721XFSource type: Electronic(1
Kinetic and spectroscopic properties of carbene-diazirine ylides
No full textThe formation of a metastable carbene-diazirine ylide (CDY), characterized by an UV absorption spectrum in the range of 270-290 nm and yielding azine by rearrangement, is shown to be a general process in the photolysis of diazirines. However, the yield of formation and the lifetime of CDY greatly depend on the system considered. The decreasing value of the rate constant of the reaction, carbene + diazirine --> CDY, from similar to 10(9) M-1 s(-1) for singlet dialkylcarbenes, Ad: (adamantylidene) and BCN: (bicyclo[3.3.1]non-9-ylidene), to similar to 10(8) M-1 s(-1) for benzylchlorocarbene and to similar to 10(6) M-1 s(-1) for cyclopropyl and phenylchlorocarbenes, reflects the decreasing reactivity of these carbenes. The lifetime of these ylides is determined by the value of the activation energy barrier for their rearrangement to azine, E-a approximate to 15.5 kcal/mol for dialkylcarbenes, approximate to 11.5 kcal/mol fur alkylchlorocarbenes, and <10 kcal/mol for phenylchlorocarbene. This decrease of E-a is related to the strong stabilization of the azine when proceeding from CR2=N-N=CR2 to Ph-CCl=N-N=CCl-Ph. Another mechanism for the formation of azine, by a second-order reaction of the diazo isomer of the diazirine, is clearly identified in the case of photolysis of the BCN(N-2) diazirine.PT: J; CR: BONNEAU R, 1989, J AM CHEM SOC, V111, P5974 BONNEAU R, 1992, J PHOTOCH PHOTOBIO A, V68, P97 BONNEAU R, 1997, PURE APPL CHEM, V69, P979 BONNEAU R, 1998, J PHOTOCH PHOTOBIO A, V116, P9 BRINKER UH, 1998, ADV CARBENE CHEM, V2 DOYLE MP, 1987, J ORG CHEM, V52, P1619 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 JACKSON JE, 1988, J AM CHEM SOC, V110, P5595 LIU MTH, 1992, J AM CHEM SOC, V114, P3604 LIU MTH, 1992, J ORG CHEM, V57, P2483 LIU MTH, 1992, J PHOTOCH PHOTOBIO A, V63, P115 LIU MTH, 1994, INT J CHEM KINET, V26, P1179 LIU MTH, 1994, J PHOTOCH PHOTOBIO A, V84, P133 LIU MTH, 1994, RES CHEM INTERMEDIAT, V20, P195 LIUEAU R, 1989, J PHYS CHEM-US, V93, P7300 MERRER DC, 1998, J ORG CHEM, V63, P3010 MOSS RA, 1990, J AM CHEM SOC, V112, P1638 MOSS RA, 1990, J AM CHEM SOC, V112, P5642 OIDA S, 1967, CHEM PHARM BULL, V15, P545 OIDA S, 1968, CHEM PHARM BULL, V16, P654 SHUSTOV GV, 1999, CAN J CHEM, V77, P540 TURRO NJ, 1980, J AM CHEM SOC, V102, P7576; NR: 22; TC: 8; J9: J PHYS CHEM A; PG: 6; GA: 311EYSource type: Electronic(1
Benzylchlorocarbene: origins of Arrhenius curvature in the kinetics of the 1,2-H shift rearrangement
No full textBenzylchlorocarbene (1, BCC) was generated photochemically from benzylchlorodiazirine (2) in isooctane, methylcyclohexane (MCH), and tetrachloroethane (TCE) at temperatures from similar to 30 to -75 degrees C. At -70 degrees C in isooctane, the identified products included Z/E-beta-chlorostyrenes 4 (46.6%), alpha-chlorostyrene 5 (2.4%), 1,1-dichloro-2-phenylethane 6 (1.9%), a BCC-isooctane insertion product 8 (5.5%), carbene dimers 9 (3.8%), and azine 3 (30%). The significant incursion of intermolecular products 3, 8, and 9 implies that laser flash photolytic (LFP) kinetic data for the decay of BCC obtained at low temperature is biased and should not be employed in Arrhenius analyses. Accordingly, previously obtained curved Arrhenius correlations for BCC do not necessarily implicate quantum mechanical tunneling (QMT) in the 1,2-H shift rearrangement of BCC to 4. Similarly in MCH, where BCC affords a solvent insertion product in similar to 44-53% yield, the curved Arrhenius correlation (Figure 1) cannot be readily interpreted. In polar solvents such as TCE, clean H-shift reactions of BCC are obtained even at -71 degrees C; an Arrhenius correlation of LFP kinetic data is linear from 3 to -71 degrees C (Figure 2), affording E-a = 3.2 kcal mol(-1) and log A = 10.0 s(-1). Therefore, QMT does not appear to play a major role in the 1,2-H shift rearrangement of BCC at ambient or near ambient temperature in solution.PT: J; CR: BONNEAU R, 1996, J AM CHEM SOC, V118, P3829 DEAN JA, 1992, LANGES HDB CHEM DIX EJ, 1993, J AM CHEM SOC, V115, P10424 DOX AW, 1941, ORG SYNTH, V1, P5 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 ISAACS NS, 1995, PHYSICAL ORGANIC CHE, P304 JACKSON JE, 1988, J AM CHEM SOC, V110, P5595 KAZANIS S, 1991, J PHYS CHEM-US, V95, P4430 KEATING AE, 1997, COMMUNICATION 0804 LAVILLA JA, 1989, J AM CHEM SOC, V111, P6877 LAVILLA JA, 1990, TETRAHEDRON LETT, V31, P5109 LIU MTH, 1984, TETRAHEDRON, V40, P887 LIU MTH, 1985, CHEM COMMUN, P982 LIU MTH, 1985, J ORG CHEM, V50, P3218 LIU MTH, 1990, J AM CHEM SOC, V112, P3915 LIU MTH, 1992, J AM CHEM SOC, V114, P3604 LIU MTH, 1992, J PHOTOCH PHOTOBIO A, V63, P115 LIU MTH, 1994, ACCOUNTS CHEM RES, V27, P287 LIU MTH, 1994, J PHOTOCH PHOTOBIO A, V84, P133 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 MODARELLI DA, 1993, J AM CHEM SOC, V115, P470 MOSS RA, 1987, J AM CHEM SOC, V109, P4341 MOSS RA, 1990, J AM CHEM SOC, V112, P1638 MOSS RA, 1994, ADV CARBENE CHEM, V1, P59 MOSS RA, 1996, J AM CHEM SOC, V118, P12588 MOSS RA, 1997, CHEM COMMUN 0321, P617 MOSS RA, 1997, TETRAHEDRON LETT, V38, P7049 STORER JW, 1993, J AM CHEM SOC, V115, P10426 SUGIYAMA MH, 1992, J AM CHEM SOC, V114, P966 TOMIOKA H, 1984, J AM CHEM SOC, V106, P454 WHITE WR, 1992, J ORG CHEM, V57, P2841 WIERLACHER S, 1993, J AM CHEM SOC, V115, P8943 YEN VQ, 1962, ANN CHIM, V7, P785; NR: 33; TC: 8; J9: J ORG CHEM; PG: 7; GA: ZM109Source type: Electronic(1
Embryonic expression of the human MID1 gene and its mutations in Opitz syndrome
No full textOpitz syndrome (G/BBB syndrome, MIM145410, and MIM300000) is a midline congenital malformation characterised by hypertelorism, hypospadias and oesophagolaryngotracheal defects leading to swallowing difficulties and hoarse voice. This condition is genetically heterogeneous with an X-linked recessive form mapped to Xp22.3 and at least one autosomal dominant form mapped to chromosome 22q11.2. Recently, mutations in MID1 have been identified in the X-linked form of the disease but the gene for the autosomal dominant form on 22q11 remains unknown.
Here we report on MID1 mutations screening in a series of 14 patients with Opitz syndrome and the MID1 expression pattern in human embryos using hybridisation in situ. Finally, we investigated the contribution of chromosome X-inactivation studies to identify the X-linked form of the disease.
Six MID1 mutations were identified in our series. All mutations were novel except the R495X mutation previously reported in three unrelated patients. We report heart and hindbrain expression of MID1 during early human development. Obligate carrier mothers showed a random pattern of X-inactivation.
Vermis hypoplasia or agenesis was frequently present (4/9) in patients with MID1 mutation. The heart and hindbrain expression of MID1 during early human development further supports the view that heart defects and vermis hypoplasia or agenesis are features to be included in the malformative spectrum of the syndrome. Finally, the study of X-inactivation pattern in women does not help discrimination between X-linked and autosomal forms of the disease
Comment on “Repulsion between calcite crystals and grain detachment during water-rock interaction” by Levenson and Emmanuel, 2017
No full textInternational audienceforces between calcite surfaces and their effect on the brittle strength of calcite-bearing rocks. Geophysical Research Letters 42, 4786-479
Inferior Thyroid Artery Injury After Attempts of Internal Jugular Venous Catheterization
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