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Query: UMLS:C0027819 (
neuroblastoma
)
27,800
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Tyrosine hydroxylation was studied in intact cells of mouse
neuroblastoma
clone N1E-115 which have high levels of tyrosine 3-monooxygenase (EC 1.14.16.2) and which have been fully characterized for tyrosine transport. Measurement of [3H]OH formed from L-[3,5(-3)H]tyrosine in the medium was the method of assay and [3H]OH formed was stoichiometric with the formation of L-[3H]
3,4-dihydroxyphenylalanine
. Tyrosine hydroxylation was dependent on time of incubation, cell number, and the concentration of [3H]tyrosine in the medium. From velocity vs. [3H]tyrosine concentration experiments, two apparent Km values were obtained: Km1 = 10 +/- 2 microM; Km2 = 140 +/- 10 microM. Substrate inhibition occurred with tyrosine concentrations between 20 and 50 microM. The reaction was twice as fast at pH 5.5 as at pH 7.4. alpha,alpha'-Dipyridyl (1 mM) caused major inhibition (75%) when [3H]tyrosine concentration was 10 microM. L-3-Iodotyrosine was a competitive inhibitor with Ki = 0.3 microM. Dopamine was a non-competitive inhibitor with Ki = 500 microM. 1-Norepinephrine had no effect. These results show that the hydroxylation of tyrosine by living N1E-115 cells has many of the properties of the reaction catalyzed by purified tyrosine 3-monooxygenase from normal tissue.
...
PMID:Properties of tyrosine hydroxylation in living mouse neuroblastoma clone N1E-115. 1217 May 97
Amyloid-beta peptide (Abeta) is the toxic agent in Alzheimer's disease (AD), although the mechanism causing the neurodegeneration is not known. We previously proposed a mechanism in which excessive Abeta binds to regulatory heme, triggering functional heme deficiency (HD), causing the key cytopathologies of AD. We demonstrated that HD triggers the release of oxidants (e.g., H(2)O(2)) from mitochondria due to the loss of complex IV, which contains heme-a. Now we add more evidence that Abeta binding to regulatory heme in vivo is the mechanism by which Abeta causes HD. Heme binds to Abeta, thus preventing Abeta aggregation by forming an Abeta-heme complex in a cell-free system. We suggest that this complex depletes regulatory heme, which would explain the increase in heme synthesis and iron uptake we observe in human
neuroblastoma
cells. The Abeta-heme complex is shown to be a peroxidase, which catalyzes the oxidation of serotonin and
3,4-dihydroxyphenylalanine
by H(2)O(2). Curcumin, which lowers oxidative damage in the brain in a mouse model for AD, inhibits this peroxidase. The binding of Abeta to heme supports a unifying mechanism by which excessive Abeta induces HD, causes oxidative damage to macromolecules, and depletes specific neurotransmitters. The relevance of the binding of regulatory heme with excessive Abeta for mitochondrial dysfunction and neurotoxicity and other cytopathologies of AD is discussed.
...
PMID:Amyloid-beta peptide binds with heme to form a peroxidase: relationship to the cytopathologies of Alzheimer's disease. 1649 52
Catecholamines are biogenic amines that play an important role in the nervous system. Some catecholamines have been used as tumor makers of phenochromocytoma, paraganglioma and
neuroblastoma
. The analysis of total catecholamine metabolites should be useful for one-shot screening of multiple aspects of diseases; however, it is difficult to do this, because the catecholamine metabolites are divided into three groups: five amines, one amino acid and three carbonic acids. Catecholamines and small molecules were separated from plasma proteins by an internal-surface reversed-phase column (protein-coated octadeyclsilica column) and were analyzed by liquid chromatography (LC)/mass spectrometry (MS) using electrospray ionization time-of-flight MS. Using a reversed-phase column and hydrophilic mobile phases, we succeeded in the separation of nine catecholamines, all of which had similar structures. These nine substances were eluted in the following order: norepinephrine, epinephrine, normetanephrine, dopamine, metanephrine,
3,4-dihydroxyphenylalanine
, vanillomandelic acid, 3,4-dihydroxyphenylacetic acid and homovanillic acid. The reproducibility of this method was acceptable. The highest coefficient of variation was 7.4%. In addition, various types of compounds were separated from and detected in plasma proteins by applying LC/MS. The plasma direct injection method, which uses an internal-surface reversed-phase column and an ion-pair reagent, allowed us to separate small molecules from plasma proteins. MS detected some compounds that high-performance LC could not succeed in separating and detecting with UV detection. We think that the method can be applied to find new markers in
neuroblastoma
, by comparing the plasma of patients with that of normal infants. The method can be also used to help in making a diagnosis of other diseases and finding their new makers.
...
PMID:Pretreatment and one-shot separating analysis of whole catecholamine metabolites in plasma by using LC/MS. 1679 60
We evaluated the feasibility and usefulness of reverse transcriptase-polymerase chain reaction (RT-PCR) on fine-needle aspirates for categorization of small blue round cell tumors (SBRCTs). A total of 51 cases, including 25 Ewing sarcoma/peripheral primitive neuroectodermal tumors (PNETs), 11 rhabdomyosarcomas, 13 neuroblastomas, and 2 desmoplastic small round cell tumors (DSRCTs) were analyzed. The detection of the EWS-FLI1 (20/25) and EWS-ERG (4/25) fusion transcripts resolved 24 of 25 cases of Ewing sarcoma/PNET. The PAX3/7-FKHR fusion transcript was detected in 2 of 4 cases of alveolar rhabdomyosarcoma and the EWS-WT1 transcript in both cases of DSRCT. Tyrosine hydroxylase and
3,4-dihydroxyphenylalanine
(dopa) decarboxylase transcripts were demonstrated in 10 of 13 cases of
neuroblastoma
. In comparison, immunocytochemical analysis resolved 19 (76%) of 25 Ewing sarcomas, 9 (82%) of 11 rhabdomyosarcomas, 6 (46%) of 13 neuroblastomas, and 1 (50%) of 2 DSRCTs. Overall, RT-PCR resolved 38 (86%) of 44 vs 35 (69%) of 51 cases by immunocytochemical analysis. RT-PCR is easily applied to fine-needle aspirates of SBRCT and greatly facilitates accurate tumor typing.
...
PMID:Reverse transcriptase-polymerase chain reaction as an ancillary molecular technique in the diagnosis of small blue round cell tumors by fine-needle aspiration cytology. 2023 17
Our purpose was to evaluate the diagnostic role of
18
F-
3,4-dihydroxyphenylalanine
(DOPA) PET/CT at the time of staging in children with
neuroblastoma
and to investigate its ability to assess treatment response. We also investigated the prognostic value of
18
F-DOPA PET/CT at the same time points.
Methods:
We enrolled children with
neuroblastoma
at onset. Before and after induction chemotherapy, all patients underwent
18
F-DOPA PET/CT and
123
I-metaiodobenzylguanidine (MIBG) scanning plus SPECT/CT.
18
F-DOPA PET/CT results were compared with those of
123
I-MIBG whole-body scanning (WBS). For each modality, patient-based analysis and lesion-based analysis were performed and sensitivity was calculated. We applied scoring systems to
123
I-MIBG scanning and
18
F-DOPA PET/CT (i.e.,
123
I-MIBG WBS score and whole-body metabolic burden [WBMB], respectively) and evaluated the association between these parameters, the principal
neuroblastoma
risk factors, and outcome.
Results:
We enrolled 16 high-risk and 2 intermediate-risk
neuroblastoma
patients. On patient-based analysis, sensitivity in detecting primary tumors, soft-tissue metastases, and bone or bone-marrow metastases was 83%, 50%, and 92%, respectively, for
123
I-MIBG WBS versus 94%, 92%, and 100%, respectively, for
18
F-DOPA PET/CT. On lesion-based analysis, the sensitivity of
18
F-DOPA PET/CT in detecting soft-tissue and bone or bone-marrow metastases was 86% and 99%, respectively-significantly higher than that of
123
I-MIBG WBS, at 41% and 93%, respectively. After therapy, on patient-based analysis, the sensitivity in detecting primary tumors, soft-tissue metastases, and bone or bone-marrow metastases was 72%, 33%, and 38%, respectively, for
123
I-MIBG WBS versus 83%, 75% and 54%, respectively, for
18
F-DOPA PET/CT. On lesion-based analysis, the sensitivity of
18
F-DOPA PET/CT in detecting soft-tissue and bone or bone-marrow metastases was 77% and 86%, respectively-significantly higher than that of
123
I-MIBG WBS, at 28% and 69%, respectively. During follow-up, 8 cases of disease progression and 5 deaths occurred. On multivariate analysis, only posttherapeutic
18
F-DOPA WBMB (>7.5) was associated with progression-free survival.
Conclusion:
18
F-DOPA PET/CT is more sensitive than
123
I-MIBG WBS in staging
neuroblastoma
patients and evaluating disease persistence after chemotherapy. In a time-to-event analysis, posttherapeutic
18
F-DOPA WBMB remained the only risk factor associated with disease progression.
...
PMID:Diagnosis, Treatment Response, and Prognosis: The Role of
18
F-DOPA PET/CT in Children Affected by Neuroblastoma in Comparison with
123
I-mIBG Scan: The First Prospective Study. 3154 Oct 36
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