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  • 1
    ISSN: 1432-0533
    Keywords: Key words Serotonin ; Thiamine deficiency ; Immunohistochemistry ; Vulnerability ; Degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined changes in 5-hydroxytriptamine (5-HT, serotonin) neurons in pyrithiamine-induced thiamine deficiency in mice immunohistochemically. Extensive decreases in the densities of 5-HT-immunoreactive fibers were detected in the lateral septal nucleus, the thalamus, the medial mammillary nucleus, the dorsal and the median raphe nuclei, the raphe obscurus nucleus, the tegmental area, the cerebellum and the vestibular nucleus, though only a small decrease was detected in the inferior colliculus. Most remarkably, degenerative winding fibers were detected between the deep mesencephalic nucleus and the ventral tegmental area. Increases in intensity of 5-HT immunoreactivity in the dorsal raphe nucleus and decreases in the number of 5-HT-immunoreactive cell bodies in the dorsal and the median raphe nuclei were detected. These results demonstrated the differential vulnerability of 5-HT neurons in thiamine-deficient mice. This is the first report to demonstrate changes in 5-HT neurons immunohistochemically throughout the brain of pyrithiamine-induced thiamine deficient mouse.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0568
    Keywords: Key words Tissue culture ; Hepatocyte ; Cholangiocyte ; Structural organization ; Ontogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We applied organotypic slice culture of neonatal mouse liver tissues to maintain the parenchymal cells in ontogenesis and to investigate their proliferation and differentiation. Cultured tissue spread gradually over 3 weeks. Small basophilic cells formed several layers in the center of the cultured tissues, and a monolayer of polygonal cells was seen at the periphery. Albumin- and α-fetoprotein-immunoreactions were seen in polygonal cells, as were proliferating cell nuclear antigen-immunoreactions. Connexin 32- and 26-immunoreactions were observed in small plaques on the membrane of the polygonal cells, and electron microscopy showed gap junctional complexes. Ultrastructurally, polygonal cells had a round nucleus and abundant cytoplasmic organelles, and bile canaliculi were seen on the cytoplasmic membrane. Cytokeratin 19-immunoreactions were scattered in clusters. There were ultrastructurally bile-duct-like structures with microvilli on the inner surface of the cavity and tight junctions between their constitutent cells. Quantitative analysis of albumin-, α-fetoprotein- and cytokeratin 19- or proliferating cell nuclear antigen-immunoreactivity in parenchymal cells showed changes of their phenotypes or maintenance of their proliferation in tissue culture. Our slice-culture system enabled us to maintain and to develop parenchymal cells in the liver tissue for at least 3 weeks. The findings suggest that organotypic slice culture applied to liver tissues in ontogenesis may be a useful tool not only to maintain parenchymal cells but also to investigate their proliferation and differentiation.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1433-0350
    Keywords: Key words Diffuse astrocytoma ; Bilateral thalamic astrocytomas ; Computed tomography ; Magnetic resonance imaging ; Hyperfractionated radiotherapy ; Chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report the case of a 13-year-old girl with diffuse bilateral thalamic astrocytomas. Incoordination was observed at the onset. Cranial computed tomography (CT) showed enlarged thalami, and magnetic resonance imaging (MRI) revealed these lesions to be symmetrically enlarged with high intensity on the T2-weighted image. Owing to these atypical findings in the neuroimaging studies, we had difficulty in making the correct diagnosis of a brain tumor. After the diagnosis of diffuse bilateral thalamic astrocytomas was obtained, we performed hyperfractionated radiotherapy followed by chemotherapy. Radiation therapy was effective for a while, but the girl's condition deteriorated again and she died 8 months after admission. Although diffuse bilateral thalamic astrocytomas are difficult to diagnose because they do not resemble most other neoplasms on neuroimaging studies, pediatricians should keep this entity in mind in order to arrive at a precise and prompt diagnosis.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1861-387X
    Keywords: Glioma ; Aberrant EGFR ; Xenograftic tumor ; MB-1 ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The most common alteration of the epidermal growth factor receptor (EGFR) gene in human malignant gliomas is an in-frame deletion of exon 2–7 from the extracellular domain. To study the relationship between the expression of this aberrant EGFR and cell proliferation, as well as apoptosis in malignant gliomas, we have developed U-87MG cell transfectants that express the aberrant (mutant-type) or normal (wild-type) EGFR. We analyzed cell number, tumor volume, and MIB-1 positive rate as proliferation markers, and found that in tissue culture, tumors derived from U-87 MG cells (mutant-type) have the same proliferative activity as those derived from U-87 MG cells (wild-type). However, when cells expressing mutant EGFR were implanted into nude mice subcutaneously, the tumorigenic capacity was much enhanced. We also found that the apototic index of tumors derived from U-87 MG cells (mutant-type) was less than 0.1%, whereas that of wild-type tumor was 1%. These results suggest that aberrant EGFR affects the malignancy of glioma by stimulating proliferation and inhibiting apoptosis.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Different protocols are described for the combined staining method by which argyrophilic nucleolar organizer region sites can be evaluated in human astrocytes that are immunoreactive for glial fibrillary acidic protein. Among the four protocols studied, the following method was superior to others in terms of unambiguous visualization of the regions in glial fibrillary acidic protein-positive astrocytes; the first step was immunostaining for the protein with a blue colour reaction of alkaline phosphatase, followed by sequential colloidal silver staining for the regions. By this double staining method, we have demonstrated that the reactive astrocytes found in white matter around the metastatic lesion of carcinoma and the infarction, contain more argyrophilic nucleolar organizer regions in terms of the count as well as the area than glial fibrillary acidic protein-positive astrocytes present in the white matter of the normal brain. In conclusion, the double staining may provide valuable information on the cellular activity of astroglia when performed on routine formalin-fixed paraffin sections of the human brain.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0173-0835
    Keywords: Restriction landmark genomic scanning ; DNA methylation ; CpG island ; NotI enzyme ; Transcription ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The DNA methylation status of a large number of genomic loci is visualized simultaneously and quantitatively as two-dimensional gel spots in the newly developed restriction landmark genomic scanning with a methylation-sensitive restriction enzyme (RLGS-M). Here, we demonstrate that RLGS-M using NotI as a methylation-sensitive enzyme could also scan gene loci of mammalian genomes, since almost all of the NotI loci corresponding to randomly chosen RLGS-M spots were located near or in transcriptional units (6 out of 7 NotI-linking clones) when mouse brain genomic DNA was used. This supports the previous prediction that most NotI sites are located in CpG islands (Lindsay and Bird, Nature 1987, 327, 336-338). Furthermore, beginning with RLGS-M spots we examined how to approach their corresponding RNA messages, whose expression may be associated with methylation. We compared RLGS-M patterns among various developmental stages of the mouse brain from embryonic day 9.5 to postnatal 8 weeks or among in vitro cell lines, and detected alterations of RLGS-M spots which were due to methylation of NotI sites. Two experiments using NotI-linking clones or polymerase chain reaction (PCR) were carried out to approach to their corresponding RNA messages. Consequently, we isolated two PCR-amplified clones (# 15 and # 91) which corresponded to methylatable loci and gave positive signals to mRNA from the adult brain. Furthermore, we identified two NotI-linking clones (C211 and C198) whose corresponding NotI loci localized near or at transcriptional units and were methylated in cell lines. Thus, RLGS-M is expected to be widely applicable for the isolation of tissue-specific genes whose genomic loci are associated with DNA methylation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We have developed a new genome scanning method (restriction landmark genomic scanning (RLGS)), based on the new concept of using restriction enzyme sites as landmarks. RLGS employs direct end labeling of the genomic DNA digested with a restriction enzyme and two-dimensional electrophoresis with high-resolution. Its advantages are: (i) high-speed scanning ability, allowing simultaneous scanning of thousands of restriction landmarks; (ii) extension of the scanning field using different kinds of landmarks in an additional series of electrophoresis; (iii) application to any type of organism because of direct-labeling of restriction enzyme sites and no hybridization procedure; and (iv) reflection of the copy number of the restriction landmark by the spot intensity which enables distinction of haploid and diploid genomic DNAs. The RLGS method has various applications because it can be used to scan for physical genomic DNA states, such as amplification, deletion and methylation. The copy number of the locus of a restriction landmark can be estimated by the spot intensity to find either an amplified or deleted region. The methylation state of genomic DNA can also be discovered by use of a methylation-sensitive restriction enzyme sites as a restriction landmark (restriction landmark genomic scanning for screening methylated sites, RLGS-M). This article introduces the basic principle of RLGS and its applications to the analysis of cancer, mouse mutant DNAs and tissue-specific methylation, showing the usefulness of RLGS for a variety of biological fields.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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