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  • 1
    Electronic Resource
    Electronic Resource
    Characterization of the Phosphoinositide-Linked Dopamine Receptor in a Mouse Hippocampal-Neuroblastoma Hybrid Cell Line (1998)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 71 (1998), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Previous studies have established that dopamine (DA) can stimulate phosphoinositide (PI) metabolism in the CNS and in the periphery. The present study summarizes our attempt to find a cell line that expresses this dopaminergic system. We describe that the stable clonal HN33.11 cell line, established by fusion of mouse hippocampal cells with neuroblastoma cells (N18TG2) that originate from A/J mouse, natively expresses the D1 DA receptor system that couples to PI hydrolysis. In this cell line, 500 µM DA or SKF38393 produced 43 and 75% increases in inositol phosphate (IP) accumulations, respectively. In contrast, noradrenaline or 5-hydroxytryptamine did not affect IP accumulations. The formation of IP that was stimulated by DA or SKF38393 was selectively blocked by the D1 DA receptor antagonist SCH23390 with IC50 values of 13 and 16 µM. This response was not mediated by the D1A DA receptor and was cyclic AMP-independent, as HN33.11 cells did not express this receptor, and DA or SKF38393 was unable to stimulate the formation of cyclic AMP. In Ca2+-free/100 µM EGTA medium, basal IP level was reduced by 31.5%, but SKF38393-stimulated PI hydrolysis was not affected. SKF38393-stimulated IP accumulation was also not affected by pertussis toxin (PTX) treatment (200 ng/ml), suggesting that this dopaminergic response is mediated by PTX-insensitive G proteins. Co-immunoprecipitation studies indicated that in membranes of HN33.11 cells, D1-like binding sites are coupled to Gαq protein. Blockade of SKF38393-induced PI hydrolysis with antiserum against phospholipase C (PLC) isozymes, performed in permeabilized cells, as well as co-immunoprecipitation studies implicate PLCβ3 and PLCβ4 in this dopaminergically mediated PI hydrolysis cascade. The results indicate that HN33.11 cells express a D1-like DA receptor that couples to PLCβ3/4 via Gαq protein. These cells may therefore be a useful model system for investigating this receptor system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1998.71051935.x
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  • 2
    Electronic Resource
    Electronic Resource
    The Influence of the p-Alkyl Substituent on the Isomerization of o-Quinones to p-Quinone Methides: Potential Bioactivation Mechanism for Catechols (1995)
    s.l. : American Chemical Society
    Chemical research in toxicology 8 (1995), S. 537-544 
    Details
    ISSN: 1520-5010
    Source: ACS Legacy Archives
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/tx00046a007
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  • 3
    Electronic Resource
    Electronic Resource
    Thyroid hormone regulation of Xenopus laevis metamorphosis: functions of thyroid hormone receptors and roles of extracellular matrix remodeling (1998)
    Oxford, UK : Blackwell Science
    Wound repair and regeneration 6 (1998), S. 0 
    Details
    ISSN: 1524-475X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The regulatory effects of the thyroid hormone on amphibian metamorphosis is mediated by thyroid hormone receptors. Using Xenopus laevis as a model system, we and others have shown that the mRNA levels of thyroid hormone receptors and 9-cis retinoic acid receptors, which form the functional heterodimers with thyroid hormone receptors, are regulated temporally in a tissue-dependent manner so that high levels of their mRNAs are present in an organ when metamorphosis is occurring. By overexpressing thyroid hormone receptors, 9-cis retinoic acid receptors, or both into developing Xenopus embryos, we have shown that both thyroid hormone receptors and 9-cis retinoic acid receptors are required for mediating the effects of thyroid hormone on embryo development and precocious but specific regulation of the genes, which are normally regulated by thyroid hormone during metamorphosis. Analyses of the developmental expression of one class of thyroid hormone response genes, which encode extracellular matrix-degrading metalloproteinases, suggest that extra cellular remodeling plays an important role during tissue remodeling, including cell death (apoptosis) and cell proliferation and differentiation. This effect of extracellular matrix on cell behavior has been supported directly by in vitro primary cell culture experiments, in which intestinal epithelial cells undergo thyroid hormone-induced apoptosis, just like that during natural metamorphosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1524-475X.1998.60407.x
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  • 4
    Electronic Resource
    Electronic Resource
    Enhancement of the sensitivity and selectivity of oxidation of H2O2 on platinum wire at low working potential by platinization and covering of heteropolypyrrole film for amperometric micro-biosensor construction (1999)
    Springer
    Fresenius' journal of analytical chemistry 363 (1999), S. 246-250 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A microelectrode for glucose determination was constructed by immobilization of glucose oxidase (GOx) on a platinized platinum (Pt) by electrochemical polymerization of a solution containing GOx, pyrrole, and a substituted pyrrole, 4-(3-pyrrolyl)-4-oxobutyric acid. Due to platinization and covering with the polymerized heteropolypyrrole (hPPy) film, the electrode prepared showed high sensitivity to H2O2 at a low potential and significantly reduced the response to electroactive compounds, such as ascorbate, urate and 4-acetamidophenol. Working at 200 mV (vs. SCE) the electrode showed a linear response to glucose from 1.6 to 10 mM with a high sensitivity of 1 μA/mM, whereas the response to 1 mM ascorbate, urate, and 4-acetamidophenol was 0.53 μA, 18 nA and 4 nA, respectively, which was about 2.5%, 1.0% and 1.0% of that at a bare electrode. The stability of the electrode was tested at intervals of three or five days, and each test lasted about two hours. After 6 months examination, only 30% of its activity was lost.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051182
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  • 5
    Electronic Resource
    Electronic Resource
    Characterisation of endothelin-1-related protein in human adrenal cortex and in cortical lesions (1999)
    Springer
    Histochemistry and cell biology 111 (1999), S. 33-37 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Endothelin (ET)-1 is a 21-amino acid peptide with potent vasopressor and vasoconstrictive properties. Biochemical studies suggest that this peptide occurs in the adrenal cortex, where it appears to influence steroid hormone production and catecholamine release. Concomitant with our previous immunohistological study, we found ET-1 immunoreactive (IR) cells in human adrenal cortex and cortical neoplasms, but not in the medulla. These ET-1 IR cells were numerous in adenomas, but were seen only occasionally in some of the carcinomas. In the present study, the ET-1 IR protein was extracted from normal (n=5) and hyperplastic (n=3) human cortex as well as from cortical adenomas (n=10) and carcinomas (n=5). Its molecular weight, determined by SDS-polyacrylamide gel electrophoresis and immunoblotting, was 9 kD, which is lower than that of prepro-ET-1 (21 kD), but larger than that of pre-ET-1 (4.3 kD) and ET-1 (2.5 kD). The normal cortical specimens, hyperplasias, adenomas and three of the five carcinomas all contained this distinct band. The two carcinomas lacking it were associated with Conn’s syndrome. The protein may constitute a protein not previously described, but further studies are needed to determine its complete structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050330
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  • 6
    Electronic Resource
    Electronic Resource
    Argyrophilic nucleolar organizer regions (1995)
    Springer
    Histochemistry and cell biology 104 (1995), S. 145-150 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Silver staining techniques developed to demonstrate argyrophilic nucleolar organizer regions (Ag-NORs) have been widely applied in a variety of cell kinetic studies, using the mean number of AgNORs in tumour cells as a marker for malignancy of certain types of neoplasms. However, the AgNOR techniques currently available are not entirely satisfactory, as unspecific silver precipitates readily form in the sections. On the other hand, the contrast staining, may be so weak as to render identification of the AgNORs difficult. In the present study, some of the key factors influencing the outcome of AgNOR staining were evaluated in a more systematic way. A modified AgNOR staining procedure is now proposed, giving highly contrasting AgNORs with minimal unspecific silver precipitation, thus facilitating both manual and computerized counting. The new technique involves the use of microwave irradiation in order to shorten the processing time, the use of gelatin as a protective colloid, and a Farmer's solution to optimize the specificity of the technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01451573
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  • 7
    Electronic Resource
    Electronic Resource
    Sampling and determination of hydrogen cyanide in cigarette smoke (1999)
    Springer
    Fresenius' journal of analytical chemistry 364 (1999), S. 786-787 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method for sampling and determination of hydrogen cyanide in cigarette smoke is described. Cigarette smoke is filtered through a glass fiber filter paper, and only gaseous compounds, such as hydrogen cyanide, are collected in a dilute sodium hydroxide solution. The cyanide is determined spectrophotometrically at 550 nm by the isonicotinic acid–pyrazolone method. Maximum absorbance is achieved within 10 min at room temperature, and remains constant for about 20 min. Beer’s law is obeyed in the range 0.04∼0.80 μg mL–1 cyanide, with a molar absorptivity of 3.48 × 104 L mol–1 cm–1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051435
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  • 8
    Electronic Resource
    Electronic Resource
    Skeletal effects of constant and terminated use of risedronate on cortical bone in ovariectomized rats (1999)
    Springer
    Journal of bone and mineral metabolism 17 (1999), S. 18-22 
    Details
    ISSN: 1435-5604
    Keywords: Key words: bisphosphonates ; ovariectomy ; osteoporosis ; risedronate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: To study the skeletal effects of continual and terminated use of risedronate treatment on cortical bone in ovariectomized (Ovx) rats, we used risedronate (Ris), 5 μg · kg−1, by subcutaneous injections, twice per week. The middle part of the tibial shafts (Tx) were processed undecalcified for quantitive bone histomorphometry. Cortical bone and the marrow areas of the tibial shaft did not change in either sham-Ovx or Ovx rats during the 150-day experimental period. Continued administration of Ris for 150 days decreased the marrow area and increased the percentage of cortical area compared with the matching sham and Ovx group. A decrease in bone formation indices in both periosteal and endocortical surfaces of Tx in sham-operated rats between the age of 5 and 8 months was seen. Ovariectomy increased the percentage of labeled perimeter in the periosteal area, and markedly increased the percentage of eroded perimeter in the endocortical surface compared with sham control groups in 81 and 150 days. Bone formation indices of Ris treatment were increased in periosteal surfaces, and percentages of eroded perimeter were decreased more in endocortical surfaces in 150 days than in the matching sham and Ovx groups. These data matched our static data, which showed a significantly increased percentage of cortical bone area and decreased percentage of marrow area. These bone gains were not maintained in the 90-day Ris withdrawal group. For cancellous bone, the 60-day Ris-treated high bone mass was maintained in the withdrawal group and not maintained in Ris continmuously treated group. These results indicate the effects of constant and terminated use of Ris in cortical bone were different from those in trabecular bone in the proximal tibial metaphysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007740050058
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  • 9
    Electronic Resource
    Electronic Resource
    Formylferrocene 5–phenyloxazole-2–carbonylhydrazone bivalent transition metal complexes (1997)
    Springer
    Transition metal chemistry 23 (1997), S. 97-99 
    Details
    ISSN: 1572-901X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Bivalent transition metal complexes of the new ligand formylferrocene 5–phenyloxazole-2–carbonylhydrazone (HFfoh) have been prepared and characterized by elemental analyses, molar conductivities, i.r., n.m.r., u.v. spectra and thermal analyses. In all the complexes, the ligand coordinates to the metal ion via the azomethine nitrogen and enolic oxygen as a bidentate donor to give [MOAc(Ffoh)]nH2O, where OAc− also acts as a bidentate ligand.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006970320775
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  • 10
    Electronic Resource
    Electronic Resource
    Characterization of a cDNA encoding a novel plant poly(A) polymerase (1998)
    Springer
    Plant molecular biology 37 (1998), S. 729-734 
    Details
    ISSN: 1573-5028
    Keywords: poly(A) polymerase ; chloroplast RNA processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated cDNA clones encoding a novel factor (PAP-I) that is a component of a multi-subunit poly(A) polymerase from pea seedlings. The encoded protein, when isolated from appropriately engineered Escherichia coli, was active as a poly(A) polymerase, either with an associated RNA binding cofactor (PAP-III) or with free poly(A) as an RNA substrate. The latter observation indicates that PAP-I is in fact a poly(A) polymerase. PAP-I bore a striking resemblance to an as yet uncharacterized cyanobacterial protein. This observation suggested a possible chloroplast localization for PAP-I. This hypothesis was tested and found to be substantiated; immunoblot analysis identified PAP-I in chloroplast but not nuclear extracts. Our results suggest that PAP-I is a component of the machinery that adds poly(A) to chloroplast RNAs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006000213403
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