Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2005-2009
  • 1990-1994  (12)
  • Analytical Chemistry and Spectroscopy  (8)
  • Alzheimer's disease  (4)
  • 1
    ISSN: 1432-0533
    Keywords: Alzheimer's disease ; the proteinase inhibitor region of amyloid precursor proteins ; Lipofuscin ; Lysosome ; Amyloid β/A4 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The immunohistochemical localization of the proteinase inhibitor region of amyloid protein precursors (APPI) in the postmortem human neocortex was studied using a polyclonal antibody raised against a purified recombinant human APPI derivative produced by COS-1 cells. APPI-like immunoreactivity (APPI-LI) was found diffusely in the human neocortex. APPI-LI appeared as irregularly shaped granular structures. The size of the APPI-LI structures was 1–4 μm in diameter. APPI-LI usually formed a cluster of 10- to 20-μm diameter in the cortical gray matter and 20- to 40-μm diameter in the subcortical white matter. Double staining for APPI and glial fibrillary acidic protein indicated that APPI-LI in the white matter and molecular layer was localized exclusively in the fibrillary astrocytes. In contrast, APPI-LI was found in neurons as well as in the fibrillary astrocytes in layers II through to VI. Under fluorescence microscopy, APPI-LI in both neurons and fibrillary astrocytes were found in close association with lipofuscin. The present observations indicate that APPI is localized in neurons and astrocytes in the human neocortex and that APPI may be associated with lipofuscin or lysosome in the human neocortex.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0533
    Keywords: Acetylcholinesterase ; Senile plaque ; β/A4 protein ; Amygdala ; Alzheimer's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the possible relationship between acetylcholinesterase (AChE)-containing fiber density and senile plaque density and between AChE-positive plaques and β/A4 protein deposition, AChE histochemistry, the modified Bielschowsky's method and β/A4 protein immunohistochemistry were performed on the amygdala of Alzheimer's disease (AD) and aged control cases. Abundant AChE-positive senile plaques were found in the amygdala and related structures in AD. These AChE-positive plaques were mainly of the primitive or diffuse type. In addition to senile plaques of typical morphologies a variety of AChE-positive structures were observed in the amygdala and related regions in AD. A comparison of serial sections stained alternatively with AChE histochemistry and β/A4 protein immunohistochemistry has revealed that these AChE-positive structures with variable morphological appearances displayed β/A4 protein immunoreactivity, indicating that AChE is localized in a variety of β/A4 protein deposition including the diffuse plaque. Thus, it is suggested that AChE is present in some senile plaques at the earliest stage. However, there was no apparent correlation between the numerical density of AChE-positive fibers and senile plaque density. These findings suggest that the degeneration of cholinergic neurons is not attributed to the occurrence of AChE activity in β/A4 protein.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0533
    Keywords: Hirano bodies ; Unit lamellae ; Alzheimer's disease ; Rapid-freeze, deep-etch and replica ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To clarify the yet controversial fine structure of Hirano bodies, we made three-dimensional observations of the tissues from the right hippocampus obtained at autopsy of elderly patients by the quick-freeze, deep-etch and replica method. The basic structure of Hirano bodies was a unit lamella, a closely attached pair of sheets composed of parallel-running smooth filaments, 10 to 12 nm in diameter with 12-nm interspaces. In the unit lamella, filaments from each of the overlapping sheets crossed obliquely at acute or obtuse angles to form lattice-like meshworks. The unit lamellae were arranged in a folded, waved or concentric manner, and connected or supported by cross-linking filaments of the same width. The distance between these unit lamellae was about 50 nm. Occasionally the sheets were separated or fused making layers of one to three sheets. At the periphery of the bodies parallel filaments were dispersed into individual filaments of similar size or directly attached to the cytoplasmic membrane.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0533
    Keywords: Clathrin ; Alzheimer's disease ; Tangle Senile plaque
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Clathrin, which constitutes coated vesicles, plays important roles in neuronal functions. In the brains of the patients with Alzheimer's disease, distribution of clathrin was immunohistochemically investigated using four monoclonal antibodies against clathrin light chains, LCB.1, LCB.2, X-16 and CON.1, to study the involvement of clathrin in the pathology of Alzheimer's disease. LCB.1, LCB.2, X-16, and CON.1 bind to the aminoterminus of the clathrin light chain b(LCb), to the neuron-specific insert of LCb, to the light chain a(LCa), and to LCa and LCb, respectively. In Alzheimer brains, granular staining of LCB.2 around neurons in the hippocampus was weaker or patchily defected in comparison with control brains. Some neurofibrillary tangles and neurons were intensely stained in Alzheimer brains by LCB.2, whereas neurons were weakly stained in control brains. Crowns of some senile plaques in the brains of early onset Alzheimer's disease were positively stained by LCB. 2. LCB. 1 supported the observations of LCB.2. Reactive astrocytes in Alzheimer brains were intensely stained by X-16. On the other hand, Western blot analysis using LCB.2 and X-16 demonstrated no apparent differences in protein amounts and molecular weights of LCa and LCb between control and Alzheimer brains. These observations demonstrated abnormal distribution of clathrin in Alzheimer brains, implying impairment of axonal transport in this disease.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A highly sensitive and simple reversed phase high performance liquid chromatographic (HPLC) method for the quantitative determination of free fatty acids in human serum is presented. The method is based on the direct derivatization of serum fatty acids with 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionylcarboxylic acid hydrazide. The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at 37°C. The resulting derivatives are separated within 75 min on a reversed phase column (YMC Pack C8) with a gradient elution of aqueous acetonitrile and detected fluorimetrically. The detection limits are 2.5-5 fmol in a 10 μL injection volume. The sensitivity permits precise determination of free fatty acids in 5 μL serum. The method is simple and is without the conventional liquid-liquid extraction steps of serum fatty acids.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid®), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A simple and highly sensitive column-switching high performance liquid chromatographyic method with fluorescence detection for the determination of free phenylacetic acid (PAA) in human plasma and urine is described. The method is based on the direct derivatization of plasma and urine PAA with 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionylcarboxylic acid hydrazide (DMEQ-hydrazide). The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide at 37°C. The resulting DMEQ derivative of PAA is separated from endogenous interfering substances by a column-switching chromatographic system consisting of a precolumn (YMC-Pack C4) for sample clean-up and an analytical column (L-Column ODS) for the complete separation of the derivative. The derivative is detected fluorimetrically at 445 nm wih excitation at 367 nm. The detection limits (signal to noise ratio = 3) for PAA is 10 fmol in a 10 μL injection volume. The recoveries from plasma and urine are 75 and 96%, respectively. The present method is highly sensitive and simple compared to conventional liquid-liquid extraction procedures. The sensivity allows the direct determination of free PAA in an extremely small amount (5 μL) of plasma and urine.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 7 (1993), S. 162-165 
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic (HPLC) procedure for measuring pyridoxal-5′-phosphate (PLP) and certain forms of B6 vitamers in plasma is presented here. This HPLC procedure consisted of a single graphitic carbon column with a fluorescence detector employing an isocratic eluent (15% acetonitrile:1% perchloric acid: 0.05% sodium bisulfite). The graphitic carbon column is useful in acidic eluent without deteriorization. The relatively low fluorescent intensity of PLP under acidic conditions is improved by its derivatization with bisulfite in the eluent during chromatographic separation. Using this procedure, the detection limit of PLP is 50 fmol, and an aliquot of 5-50 μL of human plasma is required giving satisfactorily precise results within 5 min. We applied this method to the determination of PLP and certain B6 vitamers in human plasma after oral supplementation of pyridoxine.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three ionization methods of liquid chromatography/mass spectrometry (LC/MS) [atmospheric pressure chemical ionization (APCI), thermospray (TSP) and electrospray ionization (ESI)], were characterized by investigating the relationships between sensitivities and polarities of compounds. Log P values and mass spectrometry of three hydroxymethylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitors - pravastatin sodium (including its metabolites and related compounds), lovastatin and simvastatin - were measured. Their log P values ranged from -2.49 to 4.40, and in LC/MS each of the ionization methods gave different quasi-molecular ions and sensitivities. The APCI method showed a high sensitivity of several nanograms for hydrophobic compounds (log P 〉 2), but was not effective for hydrophilic compounds, such as glutathione conjugate. The TSP method was found to be applicable to all compounds used in this study, and was more sensitive for hydrophobic compounds. The ESI method was also applicable to all compounds (up to 20 ng), and was 10-100 times more sensitive than the other methods in the case of hydrophilic compounds. These results suggest that hydrophobicity of compounds related to efficiency of LC/MS ionization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isomerization and degradation of benzylpenicillin ((2S,5R,6R)-3,3-dimethyl-7-oxo-6-(2-phenylacetamido)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid) were studied using a combination of PlasmasprayTM (PSP) liquid chromatography/tandem mass spectrometry (LC/MS/MS) and liquid secondary ion tandem mass spectrometry (LSI MS/MS). Benzylpenicillin was isomerized to benzylpenicillenic acid (3-mercapto-N-[[5-oxo-2-(phenylmethyl)-4(5H)-oxazolylidene] methyl] valine) in the PSP interface/ion source. The isomerization was inferred from the probe temperature dependence of PSP LC tandem mass spectra and discrepancies in the daughter ions between PSP LC and LSI tandem mass spectra. High temperature at the PSP interface was responsible for the isomerization, since the difference between PSP LC and LSI tandem mass spectra became smaller as the probe temperature was lowered. It was also found that benzylpenicillin was decomposed to benzylpenilloic acid (5,5-dimethyl-2-[(phenylacetamido)methyl] thiazolidine-4-carboxylic acid), N-(phenylacetyl)glycine, N-(phenylacetyl)glycinal and 3-mercaptovaline in the PSP interface/ion source. The degradation products formed in the interface/ion source were identical to those formed in acidic solution. The results show that degradation of penicillins can be investigated by PSP LC/MS and PSP LC/MS/MS.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...