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At least 703 records · Page 39Linked to original sources
PubMed2001

Selective loss of KGDHC-enriched neurons in Alzheimer temporal cortex: does mitochondrial variation contribute to selective vulnerability?

THE RESEARCH OBJECTIVE: of this study was to test whether variation in mitochondrial composition is associated with "selective vulnerability" in Alzheimer brain. The term "selective vulnerability" refers to the loss of relatively vulnerable brain cells and the sparing of relatively resistant brain cells in disorders in which a genetic defect or environmental agent acts on both types of cells. The mechanisms underlying selective vulnerability are largely unknown, but mitochondria may be involved; the composition of mitochondria varies among different types of neurons, and mitochondria have an important role in cell death. Alzheimer's Disease (AD) is one of a number of neurodegenerative disorders in which both selective vulnerability and abnormalities of mitochondria occur. METHODS: We examined by immunohistochemistry the cellular distribution of a mitochondrial constituent (the alpha-ketoglutarate dehydrogenase complex, KGDHC) known to be deficient in AD, in relation to the known selective vulnerability of neurons in areas 21 and 22 of the temporal lobe in this neurodegenerative disorder. RESULTS: In normal human brain, cortical layers III and V contain neurons intensely immunoreactive for KGDHC, compared to other cells in these areas. The KGDHC-enriched cells are lost in AD (p < 0.001). In layer III, the loss of KGDHC-enriched cells is proportional to total loss of neurons, as determined by immunoreactivity to neuron specific enolase (NSE). In layer V, a higher proportion of the KGDHC-enriched neurons are lost than of other (NSE positive) neurons (p < 0.001). SIGNIFICANCE: Variations in mitochondrial composition may be one of the factors determining which cells die first when different types of cells are exposed to the same stress.

Aged↗
PubMedDate not supplied

The origin of extragonadal teratoma: case report of an immature teratoma occurring in a prenatal brain.

We describe a massive congenital intracranial teratoma (MCIT), which had a normal chromosome banding pattern 46,XY karyotype and a normal diploid DNA histogram, and which produced a variety of carcinoembryonic antigens. The volume density of primitive neural components (primitive neural tubes, small undifferentiated neuroepithelial cells, immature glial fibers and pigment cell components without neurofibrillar differentiation) was estimated to be 45%. We discuss the histogenesis, pathobiology and cell cycle kinetics.

Adult↗
PubMed2004

Improving recovery of spinal cord-injured rats by telomerase-driven human neural progenitor cells.

PURPOSE: Human neural progenitor cells hold great promise for treating a variety of human neurological diseases such as spinal cord injury. One of the issues limiting this technology is how to expand neural progenitor cells in vitro to obtain sufficient number of cells for clinical transplantation. We have established a homogeneous population of human neural progenitor cells (hNPC-TERT) immortalized by the human telomerase reverse transcriptase (hTERT) gene. Then we studied whether these cells could differentiate into neural cells in vivo and improve the recovery of spinal cord-injured rats. METHODS: The hNPC-TERT cells had been transplanted into the injured spinal cord and the functional recovery of the rats with spinal cord contusion injury was evaluated through BBB locomotor scale and Motor Evoked Potentials. Additionally, the differentiation of hNPC-TERT cells was shown by immunocytochemistry. RESULTS: As revealed by this animal model, hNPC-TERT cells developed into functional cells in the injured spinal cord and improved recovery from spinal cord injury in both locomotor scores and electrophysiological parameter in this animal model. CONCLUSIONS: This study is the first demonstration of the use of telomerase-driven human progenitor cells to treat spinal cord injury and should provide a new cell source for research of clinical application.

Analysis of Variance↗
PubMedDate not supplied

Treatment of metastatic neuroendocrine carcinomas based on WHO classification.

A single institution prospective trial was conducted to evaluate the efficacy of biotherapy or chemotherapy in metastatic neuroendocrine carcinomas (NECs). The choice of therapy was based on the revised histological classification criteria of the WHO in an effort to define a standardized protocol for therapy of these cancers. Patients with well-differentiated NECs (WD-NECs; n=11) received therapy with octreotide long-acting release and interferon-alpha-2b for a maximum of 1 year; cases with poorly-differentiated NECs (PD-NECs; n=8) were given combination cisplatin, L-leucovorin and 5-fluorouracil chemotherapy for a maximum of 9 cycles. Five patients (4 with WD-NECs) had carcinoid syndrome. Among the patients with WD-NECs (median follow-up 20 months, range 4-40), 4 had partial responses and 7 had stable disease. In patients with PD-NECs (median follow-up 10.5 months, range 3-30), 3 had partial response, 2 stable disease, and the disease progressed in 3 cases. The 2-year survival rate in WD-NECs and PD-NECs was 88% and 66%, respectively. Grade 3-4 side-effects were limited to 9% thrombocytopenia and 12.5% neutropenia. Both these treatment regimens had a good therapeutic index and compared favourably with those previously reported for metastatic WD-NECs and PD-NECs.

Adult↗
PubMed1991

Histogenesis and differentiation potential of central neurocytomas.

The central neurocytoma, a recently identified rare supratentorial brain tumor in young adults, is characterized by intraventricular location and a usually benign clinical course. In order to elucidate the histogenesis and differentiation potential of this neoplasm, we have undertaken an immunocytochemical and molecular biological study of four central neurocytomas. It was found by immunocytochemistry and immunoblotting that all tumors express neuron-specific enolase and synaptophysin. Western blots also revealed expression of the synaptic vesicle protein, synapsin I, neurofilament protein and glial fibrillary acidic protein in several neurocytomas which failed to exhibit immunoreactivity to these marker antigens on paraffin sections. Immunocytochemical reactions with antibodies to synaptophysin and glial fibrillary acidic protein on adjacent sections demonstrated coexpression in individual tumor cells. The neuronal form of the pp60src protein-tyrosine kinase, an oncogene-product specifically expressed in central nervous system neurons, was not detectable in two central neurocytomas investigated. N-myc, a proto-oncogene frequently amplified in childhood neuroblastomas, was present as a single copy gene in all central neurocytomas, indicating that amplification of this gene is not involved in the pathogenesis of the central neurocytoma. In accordance with ultrastructural evidence of synaptogenesis, we conclude that the central neurocytoma is a neuroectodermal tumor with consistent commitment for neuronal differentiation. Since these tumors retain a potential for additional glial differentiation, we propose an origin from bipotential progenitor cells in the periventricular matrix, which in the mammalian brain persists throughout adult life.

Adult↗
PubMed1991

[Subependymal giant cell astrocytoma].

Subependymal giant-cell astrocytomas (SEGA) are rare brain tumors. They occur typically in the walls of the lateral ventricles and very seldom in the wall of the third ventricle. In our experience, all patients with SEGA have had tuberous sclerosis. Between January 1950 and May 1990, of our 345 patients with tuberous sclerosis 22 were found to have SEGA. The diagnosis being made histologically in symptomatic cases or by clinical or neuroradiologic methods. The histological, immunohistochemical and ultrastructural features of this unique tumor are discussed. To date, histopathologic methods have not resolved the issue of whether these tumors are exclusively astrocytic or neuronal in nature, or show features of both. Modern immunohistochemical and/or molecular-biological techniques will no doubt elucidate the histogenesis of this highly characteristic, albeit polymorphous tumor.

Adult↗
PubMed1986

Studies on immunological properties of enolase from carp muscles (Cyprinus carpio) after chemical modification of some amino-acid residues.

After modification of histidine residues, enolase from carp muscles lost the ability to precipitate with antibodies against native enzyme. This ability remained after nitration of tyrosine residues, but the immunoelectrophoretic pattern--localisation and height of arcs--differed from that of native enolase. Minor changes of this pattern were found in enolase with modified tryptophan residues.

Amino Acids↗
PubMed1988

[Clinicopathological study of oligodendroglioma with special reference to immunohistochemical investigation].

The present study was undertaken to evaluate the utility of pathologic features and specific immunohistochemical studies in estimating the prognosis of oligodendroglioma. The pathological diagnosis of an oligodendroglioma was made on HE stained-sections according to WHO classification. Sixteen oligodendrogliomas, twelve mixed oligoastrocytomas and ten anaplastic oligodendrogliomas were immunotested by the peroxidase-antiperoxidase (PAP) method with anti-GFAP serum, anti-S-100 serum and anti-MBP (Myelin basic protein) serum and by the avidin biotin peroxidase-complex (ABC) method with anti-vimentin serum and ant-Leu 7 monoclonal antibody. GFAP positive cells were interpreted as reactive astrocytes, neoplastic astrocytes and neoplastic oligodendrocytes, S-100 positive cells were interpreted as reactive astrocytes and neoplastic astrocytes. Leu 7 positive cells were found in only one case of anaplastic oligodendroglioma. Anti-Leu 7 could not be considered as a specific marker for oligodendroglioma. Of the anaplastic oligodendroglioma 60% displayed MBP positively and 70% displayed vimentin positively. NSE positive cells were found in a few anaplastic oligodendrogliomas. The present study has not so far uncovered any marker that is restricted to oligodendrogliomas. However GFAP may be useful to assess the extent of reactive astrocytes and neoplastic astrocytes in the oligodendroglioma or mixed oligoastrocytoma. MBP and vimentin will help to determine the malignancy of oligodendroglioma.

Adult↗
PubMed1996

Proteins associated with RNase E in a multicomponent ribonucleolytic complex.

The Escherichia coli endoribonuclease RNase E is essential for RNA processing and degradation. Earlier work provided evidence that RNase E exists intracellularly as part of a multicomponent complex and that one of the components of this complex is a 3'-to-5' exoribonuclease, polynucleotide phosphorylase (EC 2.7.7.8). To isolate and identify other components of the RNase E complex, FLAG-epitope-tagged RNase E (FLAG-Rne) fusion protein was purified on a monoclonal antibody-conjugated agarose column. The FLAG-Rne fusion protein, eluted by competition with the synthetic FLAG peptide, was found to be associated with other proteins. N-terminal sequencing of these proteins revealed the presence in the RNase E complex not only of polynucleotide phosphorylase but also of DnaK, RNA helicase, and enolase (EC 4.2.1.11). Another protein associated only with epitope-tagged temperature-sensitive (Rne-3071) mutant RNase E but not with the wild-type enzyme is GroEL. The FLAG-Rne complex has RNase E activity in vivo and in vitro. The relative amount of proteins associated with wild-type and Rne-3071 expressed at an elevated temperature differed.

Amino Acid Sequence↗
PubMed1976

Purification and characterization of phosphoglycerate mutase from methanol-grown Hyphomicrobium X and Pseudomonas AM1.

Phosphoglycerate mutase has been purified from methanol-grown Hyphomicrobium X and Pseudomonas AMI by acid precipitation, heat treatment, ammonium sulphate fractionation, Sephadex G-50 gel filtration and DEAE-cellulose column chromatography. The purification attained using the Hyphomicrobium X extract was 72-fold, and using the Pseudomonas AMI extract, 140-fold. The enzyme purity, as shown by analytical polyacrylamide gel electrophoresis, was 50% from Hyphomicrobium X and 40% from Pseudomonas AMI. The enzyme activity was associated with one band. The purified preparations did not contain detectable amounts of phosphoglycerate kinase, phosphopyruvate hydratase, phosphoglycerate dehydrogenase or glycerate kinase activity. The molecular weight of the enzymic preparation was 32000 +/- 3000. The enzyme from both organisms was stable at low temperatures and, in the presence of 2,3-diphosphoglyceric acid, could withstand exposure to high temperatures. The enzyme from Pseudomonas AMI has a broad pH optimum at 7-0 to 7-6 whilst the enzyme from Hyphomicrobium X has an optimal activity at pH 7-3. The cofactor 2,3-diphosphoglyceric acid was required for maximum enzyme activity and high concentrations of 2-phosphoglyceric acid were inhibitory. The Km values for the Hyphomicrobium X enzyme were: 3-phosphoglyceric acid, 6-0 X 10(-3) M: 2-phosphoglyceric acid, 6-9 X 10(-4) M; 2,3-diphosphoglyceric acid, 8-0 X 10(-6) M; and for the Pseudomonas AMI ENzyme: 3-4 X 10(-3) M, 3-7 X 10(-4) M and 10 X 10(-6) M respectively. The equilibrium constant for the reaction was 11-3 +/- 2-5 in the direction of 2-phosphoglyceric acid to 3-phosphoglyceric acid and 0-09 +/- 0-02 in the reverse direction. The standard free energy for the reaction proceeding from 2-phosphoglyceric acid to 3-phosphoglyceric acid was -5-84 kJ mol(-1) and in the reverse direction +5-81 kJ mol(-1).

Bacteria↗
PubMed1999

[Primary small-cell bronchial cancer: value of serum tumor markers in the prognostic evaluation].

TUMOR MARKERS: We reviewed the biomedical literature searching for the most well-documented serum markers with prognostic value independent of the usual radioclinical and histological parameters of small cell lung cancer. RELATIVE PROGNOSTIC VALUES: Neuron specific enolase (NSE) would have a pretherapeutic prognostic value better than LDH (lacto-dehydrogenase) and perhaps better than serum sodium, biocarbonates, and uric acid. The superiority of NSE over serum albumin remains to be proven. Although there are only a few reports, TK (thymine kinase), TPA (tissue polypeptide antigen), Cyfra 21-1 and/or IL-2 (interleukin-2) secretion might have better pretherapeutic prognostic value than NSE. We also found that iterative blood assays to follow therapeutic effects in patients with small-cell lung cancer have not been proven to provide independent prognostic information. CONCLUSION: As medical laboratory resources must be concentrated on priority exploitable assays, the currently available data would suggest that it is not necessary to routinely measure serum tumor markers, and in particular NSE, for the prognostic evaluation of small-cell lung cancer patients.

Bicarbonates↗
PubMed2005

Cytokine-induced stable neuronal differentiation of human bone marrow mesenchymal stem cells in a serum/feeder cell-free condition.

The characteristics and multilineage differentiation potential of bone marrow mesenchymal stem cells (BM MSC) remain controversial. This study aimed to characterize human BM MSC isolated by plastic adherent or antibody selection and their neuronal differentiation potential using growth factors or chemical inducing agents. MSC were found to express low levels of neuronal markers: neurofilament-M, beta tubulin III, and neuron specific enolase. Under a serum- and feeder cell-free condition, basic fibroblast growth factor, epidermal growth factor, and platelet-derived growth factor induced neuronal morphology in MSC. In addition to the above markers, these cells expressed neurotransmitters or associated proteins: gamma-aminobutyric acid, tyrosine hydroxylase and serotonin. These changes were maintained for up to 3 months in all bone marrow specimens (N = 6). In contrast, butylated hydroxyanisole and dimethylsulfoxide were unable to induce sustained neuronal differentiation. Our results show that MSC isolated by two different procedures produced identical lineage differentiation with defined growth factors in a serum- and feeder cell-free condition.

Biomarkers↗
PubMed1995

Post-transcriptional regulation of gene expression in hippocampal neurons by glutamate receptor activation.

Previous work from this laboratory has documented that glutamate receptor activation and extracellular calcium entry into hippocampal neurons caused a long-lasting down-regulation of ligatin mRNA and protein. Here, we investigated whether glutamate reduced ligatin mRNA levels by decreasing the transcriptional activity of the gene and/or by regulating post-transcriptional RNA processing steps including mRNA stability. Using nuclear run-on assays, it was demonstrated that transcriptional activity of the ligatin gene was not significantly decreased after glutamate receptor activation. Further, Northern analysis of RNA from neurons maintained in the presence of the transcription inhibitor, alpha-amanitin, showed that glutamate shortened the half life of the ligatin message from 10 h to 58 min. This post-transcriptional destabilization of ligatin mRNA was mimicked by NMDA, dependent on Ca2+, blocked by MK801, and not affected by AMPA and kainic acid, indicating that message stability was governed by changes in intracellular calcium. Moreover, using in situ hybridization and confocal microscopy, we showed that glutamate and NMDA decreased ligatin message within dendritic and somal regions without increasing nuclear levels. These findings demonstrated that glutamate receptor activation altered neuronal gene expression posttranscriptionally by destabilizing mRNA. Our data suggest that post-transcriptional regulation of gene expression may be part of the normal receptor mediated regulatory program of plasticity and provides the first description of a glutamate receptor-modulated, calcium-dependent mechanism which rapidly destabilizes mRNA in neurons.

Animals↗
PubMed1987

An immunocytochemical demonstration of calcineurin in human nerve cell tumors. A comparison with neuron-specific enolase and glial fibrillary acidic protein.

Human central and peripheral nerve cell tumors were examined in detail using antibodies to calcineurin, glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE). Forty-eight formalin-fixed and paraffin-embedded specimens of human neuronal tumors, including 27 medulloblastomas, were examined. Calcineurin-positive cells were found in all peripheral nerve cell tumors and the two gangliogliomas, whereas 20 of the 27 medulloblastomas and one of the two cerebral neuroblastomas did not contain calcineurin-positive cells. Differentiation of cells along the neuronal lines was positively correlated with calcineurin immunoreactivity. NSE-positive cells were found in all of the tumors with the exception of the one cerebral neuroblastoma. NSE immunoreactivity was not invariably consistent with calcineurin immunoreactivity and non-neuronal cells were often positive. Calcineurin-positive cells were all devoid of GFAP, but NSE-positive cells expressed GFAP in some tumors. GFAP-immunoreactive cells were found only in central nerve cell tumors, and not in peripheral tumors. In addition, GFAP-positive cells in some tumors such as retinoblastoma and medulloblastoma morphologically revealed not only neoplastic but also reactive astrocytic features.

Biomarkers, Tumor↗
PubMed1992

Cholinergic differentiation in neurogenic basal forebrain cultures.

To study early events in the central nervous system (CNS) cholinergic development, cells from rat basal forebrain tissue were placed in culture at an age when neurogenesis in vivo is still active [embryonic day (E) 15]. The rapid mortality of these cells in defined medium, with 50% mortality after 5-10 h, was blocked completely by soluble proteins from the olfactory bulb (a basal forebrain target), extending earlier observations (Lambert, Megerian, Garden, and Klein, 1988). Treated cultures were capable of incorporating thymidine into DNA, and most cells incorporating 3H-thymidine (greater than 90%) also stained positive for neurofilament, confirming neuronal proliferation in the supplemented cultures. A small percentage of 3H-thymidine labelled cells were glial fibrillary acidic protein (GFAP) positive, but growth factors that support astroglial proliferation [epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and insulin-like growth factor (IGF-1)] were not sufficient for neuronal support. After 5 culture days with supplemented medium, almost 50% of the cells showed choline acetyltransferase (ChAT) immunofluorescence. The cholinergic neurons typically formed clusters separate from noncholinergic cells. These mature cultures did not develop if young cultures were treated with aphidicolin to block DNA synthesis. The data show that cultures of very young rat basal forebrain cells can be neurogenic, giving rise to abundant cholinergic neurons, and that early cell proliferation is essential for long-term culture survival.

Acetylcholinesterase↗