Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Variation in the copper contents of liver biopsy specimens was determined by destructive activation analysis of 39 punctates of one liver. The error of method was evaluated by repeated analysis of both the NBS standard Bovine Liver material and homogenized liver. The inhomogeneity of the biopsy specimens with regard to their copper concentrations was shown by comparison of the coefficients of variation. Because of the relatively small variability of the copper concentrations, however, the analysis of single liver punctates provides adequate information for the diagnosis and course of Morbus Wilson.
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PMID:[On the precision of copper determination in liver punctates by neutron activation analysis]. 714 21

The biological effects of ceruloplasmin have been exclusively ascribed to its roles as a copper carrier and an antioxidant. Although neuronal involvement of ceruloplasmin is closely related to aging and certain neuronal disorders, neuronal effects of ceruloplasmin are unknown and the possible modulation of membrane potential and ion channels by ceruloplasmin has not been investigated. In the present study, the membrane electrical properties of neuroblastoma cells in the presence of ceruloplasmin were studied using the patch-clamp technique. Ceruloplasmin induced a rapid and sustained membrane depolarization. This capacity of ceruloplasmin was abolished either when the copper was removed from ceruloplasmin or when ceruloplasmin was heat-inactivated. The depolarizing effect of ceruloplasmin was not due to an enhanced Ca2+ or Na+ influx but it seemed to result from a reduced K+ efflux since ceruloplasmin significantly inhibited a TEA-sensitive delayed rectifier K+ channel. To our knowledge, this is the first report which indicates that ceruloplasmin is an endogenous neuronal depolarizing factor.
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PMID:Ceruloplasmin: an endogenous depolarizing factor in neurons? 786 49

Diethyldithiocarbamate (DDC) was used to treat the neuroblastoma cell line Neuro-2a. Cell injury caused by DDC affects the calcium-binding protein calmodulin (CaM) and alters copper homeostasis in these cells. Neuro-2a cells were treated with 1 x 10(-5) M DDC for 1 h and were harvested at various time points over a 24-h period. Light microscopy of control cells showed CaM deposited around the cell periphery and along the neuritic processes. Treated cells showed the same distribution until 3 h after treatment. Electron microscopy showed CaM deposited around the cell periphery and within the cytoplasm and nucleus of control cells. Treated cells showed a time-dependent localization of CaM in relation to cellular disorganization. Staining of electrophoretic transfers by ProtoGold showed that CaM was present in all control samples and treated samples through 6 h. Atomic absorption spectrophotometry showed no difference in calcium levels between control and treated samples, but copper levels were significantly elevated. This study indicated that degenerative changes induced by DDC altered calmodulin levels. These changes may have been caused by elevated copper content within the cells and subsequent cell injury.
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PMID:Effects of diethyldithiocarbamate on calmodulin in neuroblastoma cells. 839 42

The influence of bovine serum amineoxidase (SAO), a circulating copper-enzyme, on neuronal K+ channels is described. Bovine SAO enhanced K+ channel currents in N1E-115 neuroblastoma cells in a time-dependent manner. Unlike ceruloplasmin (another copper-protein, shown as depolarizing factor in neurons), SAO had no effect on resting potential of neurons. However, pretreatment of cells with SAO inhibited ceruloplasmin-induced membrane depolarization. Although ceruloplasmin alone inhibited K+ channel currents, it further enhanced K+ channel currents in the presence of SAO. Therefore, SAO may be another endogenous modulator of neuronal K+ channels with effect and mechanisms different from those of ceruloplasmin.
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PMID:Modulation of K+ channel currents by serum amineoxidase in neurons. 860 55

An isomaltotriose-producing endo-dextranase was simply purified from cell-free culture broth of a Fusarium sp. by ethanol fractionation and consecutive column chromatographies using DEAE-Toyopearl and Bio-Gel P-100. The purified enzyme was judged to be homogeneous on PAGE and SDS-PAGE as well as isoelectric focusing. The molecular mass of the enzyme was estimated to be about 69 kDa by SDS-PAGE. The enzyme is an acidic protein with a pI of 4.6. The optimum pH and temperature were pH 6.5 and 35 degrees C, respectively. The enzyme was completely stable over the range of pH 4.5-11.8 at 4 degrees C for 24 h and at temperatures below 45 degrees C. Inactivation of the enzyme was found to be partial with 5 mM Cu2+, being about 70% inhibition and complete with 5 mM of Fe3+, Hg2+, Ag+ or NBS. The enzyme split dextran in an endo-lytic action to produce a large amount of isomaltotriose and a slight amount of isomaltose and glucose. The anomeric configurations of the reaction products formed by the enzyme were alpha-form, indicating that the alpha-glycoside linkages in the substrate are retained. The final yield of isomaltotriose from dextran T-2000 was about 62%.
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PMID:Purification and characterization of an isomaltotriose-producing endo-dextranase from a Fusarium sp. 950 22

The novel endogenous cannabinoid 2-arachidonoylglycerol (2-AG) was rapidly inactivated by intact rat basophilic leukaemia (RBL-2H3) and mouse neuroblastoma (N18TG2) cells through diffusion/hydrolysis/reacylation processes. The hydrolysis of 2-AG was inhibited by typical esterase inhibitors and by more specific blockers of 'fatty acid amide hydrolase' (FAAH), the enzyme catalysing the hydrolysis of the other 'endocannabinoid', anandamide (AEA). No evidence for a facilitated-diffusion process was found. A 2-AG-hydrolysing activity was detected in homogenates from both cell lines, with the highest levels in membrane fractions. It exhibited an optimal pH at 10, and recognized both 2- and 1(3)- isomers of monoarachidonoylglycerol with similar efficiencies. The apparent Km and Vmax values for -3H-2-AG hydrolysis were 91 microM and 29 microM and 2.4 and 1.8 nmol.min-1.mg of protein-1 respectively in N18TG2 and RBL-2H3 cells. [3H]2-AG hydrolysis was inhibited by Cu2+, Zn2+ and p-hydroxymercuribenzoate, and by 2- or 1(3)-monolinoleoyl- and -linolenoyl-glycerols, but not by the oleoyl, palmitoyl and myristoyl congeners. Purified fractions from solubilized membrane proteins catalysed, at pH 9.5, the hydrolysis of 2-AG as well as AEA. Accordingly, AEA as well as FAAH inhibitors, including arachidonoyltrifluoromethyl ketone (ATFMK), blocked [3H]2-AG hydrolysis by N18TG2 and RBL-2H3 membranes, whereas 2-AG inhibited [14C]AEA hydrolysis. FAAH blockade by ATFMK preserved from inactivation the 2-AG synthesized de novo by intact N18TG2 cells stimulated with ionomycin. These data suggest that FAAH may be one of the enzymes deputed to the physiological inactivation of 2-AG, and create intriguing possibilities for the cross-regulation of 2-AG and AEA levels.
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PMID:The novel endogenous cannabinoid 2-arachidonoylglycerol is inactivated by neuronal- and basophil-like cells: connections with anandamide. 951 56

Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used for routine analysis of small samples of human milk. The concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), phosphorus (P), and zinc (Zn) were determined in 203 milk samples from postpartum women at different stages of lactation after stepwise digestion in HNO3, HClO4, and H2O2 under heat. Validation of the procedure was achieved using certified reference material of bovine liver (NBS 1577) with mean recoveries of 103.5%. The concentrations of the above elements in milk matrix were comparable with previously reported values. The analytical results from breast milk will provide reference information for mineral studies of Brazilian mothers and breast-fed infants.
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PMID:Multielement determination in small samples of human milk by inductively coupled plasma atomic emission spectrometry. 952 47

The movement of copper ions across membrane barriers of vital organs and tissues is a priority topic in nutrition and one for which there continues to be little understanding of the mechanism. Reports of membrane-bound, copper-transporting adenosine triphosphatases (Cu-ATPases) selective for copper ions have brought new focus to the problem and prompted fresh ideas. Using a cell culture model approach, we attempted to learn whether transport into and out of cells depends on a Cu-ATPase. Measurement of transport kinetics in fibroblasts, brain glial cells, neuroblastoma cells, and placental cells showed differences in the rates of copper uptake and response to sulfhydryl reagents. BeWo cells, a human choriocarcinoma placental cell line, behaved as did Menkes fibroblasts by avidly absorbing copper but not releasing copper to the immediate environment. Further tests showed that BeWo cells did not express the transcript for the membrane-bound Cu-ATPase that has been identified with Menkes syndrome. Transcript induction, however, was achieved by growing BeWo cells on porous filters that allowed apical and basolateral surfaces to form. With transcript expression, the cells showed a capacity to release copper into the medium. BeWo cells also synthesized a form of ceruloplasmin whose structure differed from that of the plasma protein and hence may be a product of a different gene. BeWo cells may also express the gene for Wilson disease, thus linking Menkes and Wilson proteins to maternal delivery of copper. We constructed a model in which both ATPases work in concert in a vesicle-based transport mechanism. The vesicle model may help us understand the transport of copper across the placenta and all cells in general.
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PMID:Functional analysis of copper homeostasis in cell culture models: a new perspective on internal copper transport. 958 41

Metal ions such as Ca2+, Mg2+, or Zn2+, are important for many cell functions, for example, signal transduction and the modulation of enzyme activity. The relationship between apoptosis and metal cations, especially Ca2+, has been described in many reports. We have investigated the role of metal cations in the regulation of apoptosis in the mouse neuroblastoma cell line, Neuro-2A. When Neuro-2A cells were treated with ethylene diaminetetraacetic acid (EDTA), apoptosis was detected as growth inhibition, DNA fragmentation with a ladder pattern in agarose gel electrophoresis, and nuclear decomposition. However, in case of the treatment with ethylene glycol bis- (beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA), which has a higher chelating specificity for Ca2+ than EDTA, DNA fragmentation was not detected. Moreover, the apoptosis induced by EDTA was inhibited by exogenous Zn2+. The membrane permeable Zn2+ chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) also induced apoptosis of the Neuro-2A cells, and addition of equimolar exogenous Zn2+ or Cu2+, but not Mn2+ or Fe2+, prevented TPEN-induced apoptosis. The results suggest that Zn2+ may be a key regulator of apoptosis in Neuro-2A cells.
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PMID:Induction of apoptosis in Neuro-2A cells by Zn2+ chelating. 966 37

Alanyl aminopeptidase (AAP-S) was purified to homogeneity from rat liver cytosol. The molecular weight of the purified enzyme was calculated to be approximately 100,000 on Sephacryl S-200 HR and to be 90,000 on SDS-PAGE in the presence of beta-mercaptoethanol. These findings suggested that the enzyme exists as a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrates Ala-, Tyr- and Met-MCAs, and moderately hydrolyzed Arg-, Lys-, Leu-, Phe- and Lys-Ala-MCAs at pHs ranging from 7.5to 8.0. The enzyme also hydrolyzed several amino acid 4-methyl-coumaryl-7-amide (MCA) substrates. The order for k(cat)/Km values of AAP-S at the optimal pH (pH 7.5) was Lys->Met->Arg->Ala->Leu->Phe->Tyr->Lys-Ala-MCAs. It was strongly inhibited by bestatin, leuhistin, actinonin, amastatin, 1, 10-phenanthroline, PCMBS, Zn2+, Cd2+, Co2+, Cu2+ and Hg2+, and puromycin. The amino acid sequence of the first 43 residues of the enzyme was determined as Pro1-Glu-Lys-Arg-Pro5-Phe-Glu-Arg-Leu-Pro10-Thr-Glu-Val-Ser-Pro 15-Ile-Asn-Tyr-Ser-Leu20-(Cys)-Leu-Lys-Pro-Asp25-Leu-Leu- Asp-Phe-Thr30-Phe-Glu-Gly-Lys-Leu35-Glu-Ala-Ala-Ala-Gln40 -Val-Arg-Gln-. This N-terminal amino acid sequence is almost identical with those of puromycin-sensitive enkephalin-degrading aminopeptidases in rat and human brains, and the mouse neuroblastoma cell line Neuro2A. These findings suggest that the AAP-S from rat liver cytosol is a puromycin-sensitive aminopeptidase. Furthermore, with immunohistochemistry the enzyme was strongly stained in the cytosol of the rat liver cells.
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PMID:Isolation and characterization of an alanyl aminopeptidase from rat liver cytosol as a puromycin-sensitive enkephalin-degrading aminopeptidase. 968 21


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