The fatty acid composition of major glycosphingolipids (cerebrosides and sulfatides) in human cerebral white matter measured by a simple micromethod

Summary A micromethod for the investigation of the fatty acid composition of myelin glycosphingolipids (cerebrosides and sulfatides) suitable for general application in the investigation of neurological disorders, especially demyelinating diseases, is presented. Using the lipids extracted from 1 g of material these are freed of phospholipids by Florisil column chromatography and separated by thin-layer chromatography into 2 cerebroside and sulfatide fractions which are analyzed individually. The results obtained from the white matter of 13 normal adult brains are distributed within a narrow range which is most pronounced for the group of long chain fatty acids. Our results also agree with those quoted from literature.

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Zusammenfassung Es wurde eine Mikromethode zur Bestimmung der Fettsäurezusammensetzung der myelintypischen Glykosphingolipide (Cerebroside und Sulfatide) entwickelt, welche für entsprechende Untersuchungen bei verschiedenen neurologischen Erkrankungen, insbesondere Entmarkungskrankheiten, eingesetzt werden kann. Ausgehend von 1 g Gewebsmaterial werden die Lipide extrahiert, die Phospholipide an aktiviertem Florisil abgetrennt und die Glykolipide dünnschichtchromatographisch in je 2 Cerebrosid- und Sulfatidfraktionen aufgetrennt. Diese können dann einzeln untersucht werden. Die Ergebnisse der Fettsäureanalysen von 13 autoptisch gewonnenen normalen Gehirnproben erwachsener Personen besitzen nur eine geringe Streubreite, was besonders für die langkettigen Fettsäuren gilt. Die Befunde mit unserer Mikromethode stehen in guter Übereinstimmung mit den Werten anderer Autoren.

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Abbreviations FAME fatty acid methyl esters - FID flame ionisation detector - GLC gas-liquid chromatography - TLC thin-layer chromatography     

An optical micromethod for the determination of relative crystallisation rates of calcium oxalate in gels: Method and preliminary results

Summary This paper describes a new, highly efficient micromethod for the determination of relative crystallisation rates of calcium oxalate (CaOx). Crystallisation is performed in the upper layer of a gel (bactoagar, agarose) which contains one component (oxalate) of the sparingly soluble salt. Precipitation is started by pipetting Ca⁺⁺ containing solutions (in the presence and absence of crystallisation inhibitors) onto the gel. The process is followed quantitatively as a function of time by means of vertical light path photometry carrying out quasi-simultaneous multideterminations within a 50-fold multicuvette. The test volume is 0.1 ml. The method is suitable for large scale determinations. About 50 single crystallisation kinetics can be measured within 5–15 min. Testing three known inhibitors of CaOx crystal formation, relative inhibitory activities were obtained with standard errors of 1%–4%.     

A tetrazolium-based colorimetric assay for quantification of HIV-1-induced cytopathogenicity in monocyte-macrophages exposed to macrophage-colony-stimulating factor

A sensitive assay was developed for in vitro evaluation of anti-HIV agents in monocyte-macrophage cells (M/M) (a crucial target of HIV in the body). Monocyte-macrophage cells are usually poorly sensitive to the cytopathic effect induced by HIV. However, when fresh adherent monocyte-macrophage cells are cultured at relatively high density in the presence of macrophage-colony stimulating factor (M-CSF), they undergo cytolysis and die in 2–3 weeks. HIV-mediated cell-killing can thus be assessed with a method based on the reduction of the yellow colored 3-(4-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by metabolically active cells to a blue formazan, which can be measured spectrophotometrically. HIV-mediated cytopathic effect of M-CSF-exposed monocyte-macrophage cells was consistently achieved in all experiments performed under the conditions described herein. Anti-HIV activity of zidovudine (AZT) was also comparatively evaluated in M-CSF- and normal monocyte-macrophage cells both using the MTT assay and by measuring HIV-p24 antigen production in supernatants of monocyte-macrophage cells cultures, and similar results obtained with both methods. These results support the use of this colorimetric assay for broad screening of anti-HIV agents in monocyte-macrophage cells.     

微量发色底物法测定血浆肝素浓度及临床应用

目的　建立测定血浆肝素(Hp)浓度方法,探讨其临床应用可行性。方法　用微量发色底物法测定血浆Hp浓度,监测了18例肾病病人血透期间和2例DIC病人在用肝素治疗期间血浆肝素浓度。结果　标准曲线在0.1～0.8u/ml范围内成线性关系。高、中、低三种浓度回收率分别为90.1%、93.2%和91.4%。批内CV＝5.2%,批间CV＝7.1%,与TCT法有良好的相关性(