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)

The determination of protein nitrogen in feeds and wheat by microcomputer controlled titration is described. The method involves direct titration of ammonia with standard hypochlorite titrant in the presence of bromide. The titrant is delivered by an automatic buret, and the microcomputer controlled, automatically computed potentiometric end points are precise to 0.1% over a 5-fold concentration range of nitrogen. Digestions performed with both mercury and copper catalysts show comparable results. Samples are weighed before digestion by an electronic balance interfaced to the computer which records sample number and weight. An automatic pipet aliquots, dilutes, and buffers samples directly from the digestion tubes; the samples can be immediately titrated with the automatic titrator. The results for protein in NBS standards and check feed samples from an offical testing program compare closely with average values reported for these standards. Results show that feed and wheat samples contained 10-100% protein. Precision for successive aliquots of the same digests is 0.1-0.4%relative standard deviation; precision for multiple digestions of the same sample is 0.1-0.8%.
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PMID:Microcomputer controlled titration for determination of protein nitrogen in feeds and wheat. 39 95

A semiautomated method consisting of digestion of animal feeds in a block digestor and determination of ammonia by ammonia-salicylate reaction has been studied collaboratively, along with the official final action Kjeldahl method, sec. 7.016. Each collaborator analyzed 16 feed samples, tryptophan, ammonium dihydrogen phosphate NBS standard, and ammonium sulfate primary standard. Statistical analysis showed that the 2 methods agreed. The semiautomated method has been adopted as official first action.
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PMID:Collaborative study of a semiautomated method for the determination of crude protein in animal feeds. 124 27

Separation and determination of sample constituents by capillary isotachophoresis are entirely based on physical phenomena. The method has therefore been proposed as a universal reference method for ionic constituents. The present paper shows that even neutral species can be adequately determined after suitable preceding reactions. Urea was completely hydrolysed by urease (EC 3.5.1.5) to ammonia and bicarbonate, followed by direct measurement of the ammonium ion concentration by capillary isotachophoresis. Standard Reference Material No. 912a urea (National Bureau of Standards) was used as a primary standard. The analytical linear range of the method extends to 64 mmol urea per litre. The precision of the method was in the range of 1.05-2.64% (CV) and the analytical recovery of added urea was excellent (99.4%, SD 1.13%). Further proof of accuracy was obtained by analysing the NBS human reference serum (standard reference material 909). The mean result by the capillary isotachophoretic method, 9.52 +/- 0.085 mmol/l, agrees well with the reference value, 9.64 mmol/l. The results obtained by capillary isotachophoresis showed good agreement with those obtained by the coupled-enzyme method (r = 0.995).
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PMID:Isotachophoretic determination of urea-ammonium in plasma: a candidate reference method. 223 Jun 62

The effect of prolonged exposure to ammonia on fluid-phase, receptor-mediated, and adsorptive (non specific) endocytosis in cultured neuroblastoma (Neuro-2a) cells were studied using fluorescein-labeled dextran, concanavalin A conjugated with fluorescein isothiocyanate, and cationized ferritin as tracers. Ammonia treatment increased the rate of endocytosis of cationized ferritin as well as the number of cell elements involved in the process. Moreover, the number of cytoplasmic components containing acid phosphatase activity was also found to increase following ammonia treatment. In contrast, flow-cytometric analyses showed that, under experimental conditions, exposure to ammonia did not alter the intralysosomal pH and had little effect on the fluid-phase and receptor-mediated endocytosis of fluorescein-labeled dextran and concanavalin-A fluorocrome, respectively.
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PMID:Effects of prolonged exposure to ammonia on fluid-phase, receptor-mediated, and adsorptive (non specific) endocytosis in cultured neuroblastoma cells. A flow-cytometry and cytochemical study. 244 72

Human IgM kappa antibody to a membrane antigen of human tumors of neuroectodermal origin (melanoma, glioma and neuroblastoma) has been detected in the spent culture fluid of an Epstein-Barr virus (EBV)-transformed human B-lymphoblastoid cell line, L72. The chemical nature of the antigen was identified as ganglioside GD2. The antibody was purified by precipitation of L72 culture fluid with ammonia sulfate and hypotonic buffer followed by ultracentrifugation and Sephacryl S-300 super gel filtration. Approximately 27 mg of pure human IgM was obtained from 101 of spent medium. Total IgM and antibody activity recovery efficiency was 60% and 75%, respectively. The monoclonal character of the immunoglobulin produced by the L72 cell line was determined by agarose isoelectric focusing and immunofixation techniques. 1 mg of the purified IgM possessed an antibody titer endpoint to a GD2-positive melanoma cell line of 1:10,000 as assayed by immune adherence and 1:100 titer by complement-dependent cytotoxicity in vitro. The effect of pure anti-GD2 on suppression of melanoma growth in vivo was tested using a nude mouse model. Three-week-old CD-1 nude mice bearing 2-3 mm M14-A subcutaneous melanoma nodules were treated intraperitoneally with anti-GD2 and rabbit complement. Tumor growth was retarded for 25 days when compared to that of control mice receiving non-specific human IgM and complement. On Day 15, treated tumors were 80% smaller than control tumors. These result indicated that the pure human monoclonal antibody to GD2 may have potential for cancer therapy.
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PMID:Human monoclonal antibody to tumor-associated ganglioside GD2. 609 19

Cis-9,10-octadecenoamide (oleamide) was isolated from the cerebrospinal fluid of sleep-deprived mammals and shown to induce sleep in rats. The enzyme catalyzing the hydrolysis of the amide bond of oleamide as well as of anandamide, the putative endogenous ligand of cannabinoid receptors, was purified from rat liver, cloned, shown to be expressed also in brain and named fatty acid amide hydrolase (FAAH). The enzymatic synthesis of oleamide from oleic acid and ammonia by rat brain microsomes has been also described. However, no evidence has been reported so far on the neuronal origin of oleamide, necessary in order to postulate for this compound a role as a neuromodulator. Here we show for the first time that oleamide is produced by a neuronal cell type and that its biosynthesis in intact neurons is not likely to occur through the direct condensation of oleic acid and ammonia. A lipid metabolite was extracted and purified from mouse neuroblastoma N18TG2 cells through a sequence of chromatographic steps and characterized as oleamide by means of gas chromatography/electron impact mass spectrometry (GC/EIMS). The amount of oleamide, as estimated by GC analyses carried out in comparison with known amounts of synthetic oleamide, was 55.0+/-09.5 pmols/10(7) cells, compared to less than 0.7 pmol/10(7) cells for anandamide in the same cells. When N18TG2 cells were prelabeled with [14C]oleic acid and the lipids extracted and purified, a radioactive component with the same chromatographic behavior as oleamide was found whose levels: (1) were not significantly influenced by stimulation with ionomycin; (2) were slightly increased by incubation with FAAH inhibitor phenyl-methyl-sulphonyl-fluoride (PMSF); (3) appeared to correlate with [14C]oleic acid incorporation into phospholipids but not with free [14C]oleic acid levels. N18TG2 cell membranes were shown to contain an enzymatic activity catalyzing the synthesis of oleamide from oleic acid and ammonia. This activity was inhibited by FAAH selective inhibitors arachidonoyltrifluoromethylketone and methylarachidonoylfluorophosphonate, as well as by an excess of anandamide, and by PMSF at the same concentration which increased oleamide formation in intact cells. These data suggest that a FAAH-like enzyme working "in reverse" may be responsible for the formation of oleamide in cell-free preparations but not in whole cells.
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PMID:The sleep inducing factor oleamide is produced by mouse neuroblastoma cells. 934 54

Hyperammonemia is a consistent finding in many metabolic disorders. The excess ammonia (NH4Cl) interferes with brain energy metabolism possibly in part by inhibiting the tricarboxylic acid (TCA) cycle. Inhibition of the TCA cycle may result in depletion of ATP in the brain cells. In this study, the acute and chronic effect of NH4Cl (7.5 mM and 15 mM) on the metabolism of isolated neurons and neuroblastoma cells was examined. These cells were treated with NH4Cl for 15 minutes and 24 hours. Morphologic and metabolic toxicity were greater in neuroblastoma cells than in primary neurons. Following 15 minutes treatment, concentration of lactate increased significantly in neuroblastoma cells but, the concentration of other metabolites did not change significantly in neuroblastoma cells and in primary neurons. Following 24 hours treatment, the glucose utilization increased in both cell types. This high utilization of glucose in neuroblastoma cells was in concert with an increase in lactate and decrease in glutamate and ATP. In primary neurons, following 24 hours treatment, the glucose utilization significantly increased, but the concentration of the other metabolites did not change significantly. Neuroblastoma cells consumed more glucose than primary neurons in absence of NH4Cl, but generated the same amount of lactate as neurons.
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PMID:The effect of ammonium chloride on metabolism of primary neurons and neuroblastoma cells in vitro. 1109 81

N-[5-[N-(2-Amino-5-chloro-3,4-dihydro-4-oxoquinazolin-6-yl)methylamino]-2-thenoyl]-L-glutamic acid (6) and N-[5-[N-(5-chloro-3,4-dihydro-2-methyl-4-oxoquinazolin-6-yl)methylamino]-2-thenoyl]-L-glutamic acid (7), the first reported thiophene analogues of 5-chloro-5,8-dideazafolic acid, were synthesized and tested as inhibitors of tumor cell growth in culture. 4-Chloro-5-methylisatin (10) was converted stepwise to methyl 2-amino-5-methyl-6-chlorobenzoate (22) and 2-amino-5-chloro-3,4-dihydro-6-methyl-4-oxoquinazoline (19). Pivaloylation of the 2-amino group, followed by NBS bromination, condensation with di-tert-butyl N-(5-amino-2-thenoyl)-L-glutamate (28), and stepwise cleavage of the protecting groups with ammonia and TFA yielded. Treatment of 9 with acetic anhydride afforded 2,6-dimethyl-5-chlorobenz[1,3-d]oxazin-4-one (31), which on reaction with ammonia, NaOH was converted to 2,6-dimethyl-5-chloro-3,4-dihydroquinazolin-4-one (33). Bromination of, followed by condensation with and ester cleavage with TFA, yielded. The IC(50) of and against CCRF-CEM human leukemic lymphoblasts was 1.8+/-0.1 and 2.1+/-0.8 microM, respectively.
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PMID:Synthesis and in vitro antitumor activity of thiophene analogues of 5-chloro-5,8-dideazafolic acid and 2-methyl-2-desamino-5-chloro-5,8-dideazafolic acid. 1193 65

3-Aminopropanal (3-AP), a degradation product of polyamines such as spermine, spermidine and putrescine, is a lysosomotropic small aldehyde that causes apoptosis or necrosis of most cells in culture, apparently by inducing moderate or extensive lysosomal rupture, respectively, and secondary mitochondrial changes. Here, using the human neuroblastoma SH-SY5Y cell line, we found simultaneous occurrence of apoptotic and necrotic cell death when cultures were exposed to 3-AP in concentrations that usually are either nontoxic, or only cause apoptosis. At 30 mM, but not at 10 mM, the lysosomotropic base and proton acceptor NH3 completely blocked the toxic effect of 3-AP, proving that 3-AP is lysosomotropic and suggesting that the lysosomal membrane proton pump of neuroblastoma cells is highly effective, creating a lower than normal lysosomal pH and, thus, extensive intralysosomal accumulation of lysosomotropic drugs. A wave of internal oxidative stress, secondary to changes in mitochondrial membrane potential, followed and gave rise to further lysosomal rupture. The preincubation of cells for 24 h with a chain-breaking free radical-scavenger, alpha-tocopherol, before exposure to 3-AP, significantly delayed both the wave of oxidative stress and the secondary lysosomal rupture, while it did not interfere with the early 3-AP-mediated phase of lysosomal break. Obviously, the reported oxidative stress and apoptosis/necrosis are consequences of lysosomal rupture with ensuing release of lysosomal enzymes resulting in direct/indirect effects on mitochondrial permeability, membrane potential, and electron transport. The induced oxidative stress seems to act as an amplifying loop causing further lysosomal break that can be partially prevented by alpha-tocopherol. Perhaps secondary brain damage during a critical post injury period can be prevented by the use of drugs that temporarily raise lysosomal pH, inactivate intralysosomal 3-AP, or stabilize lysosomal membranes against oxidative stress.
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PMID:Human neuroblastoma (SH-SY5Y) cells are highly sensitive to the lysosomotropic aldehyde 3-aminopropanal. 1524 52

On-line analysis and control are critical for the optimization of product yields in animal cell culture. The close monitor of viable cell number helps to gain a better insight into the metabolism and to refine culture strategy. In this study, we use the oxygen uptake rate (OUR) to estimate the number of viable cell and the OUR-based feed-back control strategy for nutrients feeding to improve the efficiency of cell culture. A hybridoma cell line (HAb18) was cultured in fed-batch and perfusion model using serum free medium in 5L CelliGen Plus bioreactor (NBS Co., American) and 5L Biostat B bioreactor (Braun Co., Germany). The system and the method for online monitoring OUR in bioreactors, based on the dynamic measurement of dissolved oxygen (DO), were developed. The method of on-line cell concentration estimation was established based on the relationship between the growth of the hybridoma and the uptake rate of oxygen. This method was then used to determine OUR and the concentrations of cell, antibody, glucose, lactate, glutamine and ammonia in the bioreactors at given times. The relationship between OUR and nutrients metabolism was studied and OUR-based feed-back control strategy, which used the state deltaOUR = 0 as the regulation point, was established and used to control the rates of nutrients or medium feeding rate in the perfusion culture. The results showed that there was close relationship between OUR, concentration of live cells, productivity of antibody and consumption of glutamine. The sudden decrease in OUR may be caused by glutamine depletion, and with different delay times, the viable cell concentration and antibody productivity also decreased. The further analysis revealed the linear relationship between OUR and the density of live cells in the exponential growth phase as qOUR = (0.103 +/- 0.028) x 10(-12) mol/cell/h. These findings can be applied to the on-line detection of live cell density. Our study also indicated that by adjusting the perfusion rate with OUR-based feed-back control strategy, it is feasible to continuously increase in viable cell density and antibody concentration in the perfusion culture.
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PMID:[On-line monitoring of oxygen uptake rate and its application in hybridoma culture]. 1596 90


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