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Biomedical subjects

M Oshima

Publications and source records attributed to M Oshima.

At least 271 records · Page 15Linked to original sources
PubMed1980

[A histopathological study of the brain of patients who died of cerebral vasospasm after rupture of cerebral aneurysm (author's transl)].

It is said that cerebral angiospasm affects very seriously the prognosis of the patient with ruptured aneurysm. Of 44 patients with ruptured aneurysm who died from cerebral ischemia due to cerebral angiospasm, we performed histopathological studies of brains of 18 patients without iatrogenic factors (radical surgical operation, prolonged artificial breathing and so on). In all of the cases, cerebral infarctions were observed in the area fed by the artery with angiospasm. The size and extent of the cerebral infarction were various. In 12 cases who died in the acute stage (within 3 weeks after subarachnoid hemorrhage), those who survived longer showed more severe and wide cerebral infarction, while those who died earlier showed more localized infarction in the basal ganglia and thalamus. In 6 cases who died in the chronic stage (more than 3 weeks after subarachnoid hemorrhage), the cerebral infarction was slight. No ischemic changes were observed in the brain stem, except for secondary petechial hemorrhage due to incisural herniation in cases with extensive cerebral infarction.

Adult↗
PubMed1980

Characterization of glycosphingolipids by direct inlet chemical ionization mass spectrometry.

Permethylated derivatives of cerebrosides and ceramide di-, tri-, tetra-, and penta-hexosides were analyzed by the direct inlet ammonia chemical ionization (CI) mass spectrometry. In the CI mass spectra, the fragment ions produced by the loss of methanol from the protonated molecular ion were observed in all of the glycosphingolipids. Other fragment ions due to the cleavage of glycosidic moiety were major ones under the CI conditions. These ions provide information on the molecular species of glycosphingolipids and the sugar sequence of their oligosaccharides. Glycosphingolipids with hydroxy fatty acids could also be differentiated from those with nonhydroxy fatty acids by comparing the intensities of characteristic fragment ions. The CI method should be particularly useful in structural studies of glycosphingolipids from natural sources.

Animals↗
PubMed1978

Characterization of trimethylsilyl derivatives of cerebrosides by direct inlet-chemical ionization mass spectrometry.

Submicrogram quantities of trimethylsilyl derivatives of cerebrosides obtained from the spleen of a patient with Gaucher's disease and from bovine brain were analyzed by direct probe inlet-chemical ionization mass spectrometry, using isobutane as the reagent gas. Quasimolecular ions (QM+, M + 73) and other recognizable fragment ions produced by the successive elimination of trimethylsilanol and sugar residue gave useful information about fatty acid compositions. These ions could also be utilized for qualitative analyses of the molecular species of cerebrosides. Cerebrosides with non-hydroxy and hydroxy fatty acids could be discriminated from each other by comparing the intensities of their quasimolecular ions. Cerebrosides with saturated and monounsaturated fatty acids could also be discrimnated from each other, because the mass number decreased by two mass units in cerebrosides with monounsaturated fatty acids. It was concluded that structural information and molecular species determination could be obtained from small amounts of purified cerebrosides.

Animals↗
PubMed1977

Combined gas chromatography-chemical ionization mass spectrometry of sphingolipids. I. Glucosyl sphingosine, ceramides and cerebrosides of the spleen in Gaucher's disease.

Trimethylsilylated glucosyl sphingosine, ceramides and glucocerebrosides were analysed by combined gas chromatography (GC)-chemical ionization (CI) mass spectrometry. Isobutane, methane and ammonia were used as reactant gasses for chemical ionization. Essentially the same fragment ions were detected in the spectra with the different reactant gases. Purified glucocerebrosides isolated from the spleen of a patient with Gaucher's disease were clearly separated into their 8 molecular species by gas chromatography. Three other minor components were detected by spectrometry, and these 11 molecular species of glucocerbrosides from the spleen of the patient with Gaucher's disease have been analysed. The ceramides obtained by periodate oxidation and then alkaline reduction of the glucocerebrosides were also separated into 11 molecular species by GC-CI mass spectrometry. Molecular weight could be determined using the major fragment ion of m/e (M+-90) in the spectra of ceramides and cerebrosides. The chemical ionization method is useful for structural analysis and determination of the molecular species of sphingoglycolipids.

Adult↗