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  • 1
    Electronic Resource
    Electronic Resource
    Overexpressed Monomeric Human Acetylcholinesterase Induces Subtle Ultrastructural Modifications in Developing Neuromuscular Junctions of Xenopus laevis Embryos (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Formation of a functional neuromuscular junction (NMJ) involves the biosynthesis and transport of numerous muscle-specific proteins, among them the acetylcholine-hydrolyzing enzyme acetylcholinesterase (AChE). To study the mechanisms underlying this process, we have expressed DMA encoding human AChE downstream of the cytomegalovirus promoter in oocytes and developing embryos of Xenopus laevis. Recombinant human AChE (rHAChE) produced in Xenopus was biochemically and immunochemically indistinguishable from native human AChE but clearly distinguished from the endogenous frog enzyme. In microinjected embryos, high levels of catalytically active rHAChE induced a transient state of over-expression that persisted for at least 4 days postfertilization. rHAChE appeared exclusively as nonassembled monomers in embryos at times when endogenous Xenopus AChE displayed complex oligomeric assembly. Nonetheless, cell-associated rHAChE accumulated in myotomes of 2-and 3-day-old embryos within the same sub-cellular compartments as native Xenopus AChE. NMJs from 3-day-old DNA-injected embryos displayed fourfold or greater overexpression of AChE, a 30% increase in postsynaptic membrane length, and increased folding of the postsynaptic membrane. These findings indicate that an evolutionarily conserved property directs the intracellular trafficking and synaptic targeting of AChE in muscle and support a role for AChE in vertebrate synaptogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.62051670.x
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of Salt-Soluble Forms of Acetylcholinesterase from Bovine Brain (1994)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 63 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The hydrophilic, salt-soluble (SS) form of acetylcholinesterase (AChE) from bovine brain caudate nucleus exists mainly as a tetramer sedimenting at 10.3S (∼40%), and a monomer sedimenting at 3.4S (∼60%). The enzyme is N-glycosylated and contains similar HNK-1 carbohydrates as detergent-soluble (DS) AChE. No O-linked carbohydrates could be detected. Amino acid sequencing showed that the N terminus of SS-AChE is identical to that of DS-AChE. In tetrameric SS-AChE, two pairs of disulfide-linked dimers are associated by hydrophobic forces located in the C terminus. Antibodies were raised against a peptide identical to the last 10 amino acid residues of bovine brain DS-AChE. The peptide included the sequence of residues 574–583 (H-Tyr-Ser-Lys-Gln-Asp-Arg-Cys-Ser-Asp-Leu-OH) of the enzyme. The antibodies cross-reacted with tetrameric, but not with monomeric, SS-AChE, showing that in the latter form, the C terminus is truncated. Limited proteolysis of tetrameric SS-AChE at the C terminus led to the formation of an enzymatically active monomer, which did not react with anti-C-terminal antibody. Although the DS form of AChE contains a structural subunit that serves as membrane anchor, no anchor was detected in SS-AChE. Enzyme antigen immunoassays showed that SS-AChE reacted with all monoclonal antibodies directed against the catalytic subunit of DS-AChE, but not with monoclonal antibodies targeting the membrane-anchored subunits. From our results, we conclude that SS-AChE utilizes the same alternative splicing pattern as DS-AChE, leading to tetrameric SS-AChE devoid of the membrane anchor. The active monomer of SS-AChE is most likely derived from tetrameric forms by limited postsynthetic proteolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.63041446.x
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  • 3
    Electronic Resource
    Electronic Resource
    Subunit Association and Glycosylation of Acetylcholinesterase from Monkey Brain (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 61 (1993), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Cercopithecus monkey brain acetylcholinesterase (AChE; EC 3.1.1.7) consists of about 15% hydrophilic, salt-soluble enzyme and 83% amphiphilic, detergent-soluble enzyme. Sucrose density gradient centrifugation showed that hydrophilic, salt-soluble AChE was composed of about 85% tetramer (10.3S) and 15% monomer (3.3S). In amphiphilic, detergent-soluble AChE, 85% tetramer (9.7S), 10% dimer (5.7S), and 5% monomer (3.2S) were seen. The enzyme is N-glycosylated, and no O-linked carbohydrate could be detected. Use of two monoclonal antibodies, one directed against the catalytic subunit and the other against the hydrophobic anchor, gave new insights into the subunit assembly of brain AChE. It is shown that in tetrameric AChE, not all of the subunits are disulfide-bonded and that two populations of tetramers exist, one carrying one and the other carrying two hydrophobic anchors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1993.tb03629.x
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  • 4
    Electronic Resource
    Electronic Resource
    Feto-maternal haemorrhage associated with genetic amniocentesis: results of a randomized trial (1987)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 94 (1987), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Maternal serum alpha-fetoprotein (AFP) levels were determined before and after genetic amniocentesis (n=283) or ultrasound scan (n=268) in a group of women participating in a randomized trial of genetic amniocentesis. Increases in AFP levels were seen significantly more often after amniocentesis than after ultrasound scan (P〈0·001) and 48 women in the amniocentesis group had increases in AFP (ΔAFP) that were larger than the maximum ΔAFP (±25 μg/1) seen in the ultrasound group. If a ΔAFP of 〈25 μg/1 represents a feto-maternal haemorrhage (FMH) attributable to amniocentesis, the rate of amniocentesis-induced FMH was 17%. Such FMH was seen significantly more often after transplacental amniocentesis or after amniocentesis performed by less experienced operators. No association was detected between birthweight and FMH attributable to amniocentesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1987.tb03145.x
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  • 5
    Electronic Resource
    Electronic Resource
    Enzyme-Linked Immunosorbent Assay of the D2-Glycoprotein (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 41 (1983), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: D2 is a glycoprotein enriched in neuronal membranes and probably involved in intercellular adhesion. An immunochemical relationship between D2 and the neuronal cell adhesion molecule from chick has been demonstrated. Changes in D2 concentration in human body fluids correlate to certain neurological diseases.We here report the purification of the D2 membrane proteins from fetal and adult human brain and the demonstration of physicochemical differences between the two proteins. Enrichments of 133 times (fetal D2) and 350 times (adult D2) were found. Specific rabbit antisera against the purified D2 proteins were produced, and this enabled the setting up of an enzyme-linked immunosorbent assay for D2 quantification in human brain extracts, cerebrospinal fluids, sera, and amniotic fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1983.tb04750.x
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  • 6
    Electronic Resource
    Electronic Resource
    Quantification of the D2-Glycoprotein in Amniotic Fluid and Serum from Pregnancies with Fetal Neural Tube Defects (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 41 (1983), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: D2 is a glycoprotein existing in both membrane-bound and soluble forms. Employing a specific rabbit antibody against purified human brain D2, we developed an enzyme-linked immunosorbent assay (ELISA) for the quantification of D2 and applied it to amniotic fluids from 87 normal and 36 pathological pregnancies. With a cut-off point of 150 ng D2/ml, no false positive D2 values were obtained in any of the amniotic fluids from normal fetuses, although the alpha-fetoprotein concentrations were slightly increased in 13 cases. No false negative D2 values were found in any of the 18 investigated amniotic fluids from fetuses with anencephaly. Of 8 amniotic fluids from fetuses with spina bifida, 2 false negative D2 values were found. No false negative alphafetoprotein values were found in any of the cases with neural tube defects in this study. In 10 amniotic fluids from fetuses with other malformations, 5 samples showed raised D2 concentrations. The D2 level in sera from 10 women carrying normal fetuses and 16 women carrying malformed fetuses was also determined, but no statistically significant difference in D2 level was found in the pathological sera when compared with normal sera. It was concluded that the determination of D2 concentrations in amniotic fluid by means of the D2-ELISA may be used as an additional test in the screening of fetal malformations in early pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1983.tb04751.x
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  • 7
    Electronic Resource
    Electronic Resource
    Ratio of immunochemically determined amniotic fluid acetylcholinesterase to butyrylcholinesterase in the differential diagnosis of fetal abnormalities (1991)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 98 (1991), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. A total of 111 amniotic fluid samples, clear or blood stained, with elevated levels of alpha-fetoprotein and acetylcholinesterase was analysed by immunoassays specific for acetylcholinesterase and butyrylcholinesterase and the acetylcholinesterase/butyrylcholinesterase-ratios determined. Samples from 40 pregnancies associated with anen-cephaly, 47 pregnancies associated with open spina bifida or encephalocele and six pregnancies with fetal intrauterine death or miscarriage all had ratios of 〉0.14. All 11 pregnancies with fetal ventral wall defects had ratios 〈0.14 as had four pregnancies with normal outcome and elevated levels of alpha-fetoprotein and acetylcholinesterase. Three fetuses with both open spina bifida and ventral wall defects were associated with ratios above 0.14. These results suggest that immu-nochemical determination of acetylcholinesterase and butyrylcholinesterase can be used to distinguish pregnancies complicated by anencephaly, open spina bifida, encephalocele and miscarriage from those with ventral wall defects and samples with false positive elevated levels of alpha-fetoprotein and acetylcholinesterase. The procedure is accurate and simple to carry out and well suited to routine use in a clinical chemistry laboratory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1991.tb10311.x
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  • 8
    Electronic Resource
    Electronic Resource
    Genetic predisposition to adverse consequences of anti–cholinesterases in ‘atypical’ BCHE carriers (1995)
    [s.l.] : Nature Publishing Group
    Nature medicine 1 (1995), S. 1082-1085 
    Details
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Normal butyrylcholinesterase (BuChE)1, but not several of its common genetic variants2, serves as a scavenger for certain anti–cholinesterases (anti–ChEs). Consideration of this phenomenon becomes urgent in view of the large–scale prophylactic use of the anti–ChE, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nm1095-1082
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  • 9
    Electronic Resource
    Electronic Resource
    13.α1-Fetoprotein (1973)
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 2 (1973), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. Rocket immunoelectrophoresis suitable for both quantitation and qualitative identification of α1-fetoprotein is presented. By a slight modification of the rocket immunoelectrophoresis it is possible to detect α1-fetoprotein in serum in a concentration of about 0.1 mg/1. A simple method for the final purification of α1-fetoprotein is described. The concentration of α1-fetoprotein in cord blood from 258 newborn infants is shown to be closely related to the gestational age of the newborn infants. The confidence limits for the estimation of gestational age are± 16 days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3083.1973.tb03788.x
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  • 10
    Electronic Resource
    Electronic Resource
    16. Red Cell Carbonic Anhydrases B and C (CA B and CA C) (1973)
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 2 (1973), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. After carbamylation of unpurified haemolysates the human carbonic anhydrases B and C are determined by rocket immunoelectrophoresis. Quantitation of CA B is of diagnostic value in thyroid disorders since a definite low concentration is observed in hyperthyroidism and a less constant elevation is observed in hypothyroidism. In cord blood from newborn infants a close positive correlation is found between both CA B and CA C and gestational age. Without carbamylation it is possible to quantitate only the CA B enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3083.1973.tb03791.x
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