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Biomedical subjects

N Baumann

Publications and source records attributed to N Baumann.

At least 163 records · Page 9Linked to original sources
PubMed1978

[Study of gangliosides in normal (C57B1/6J) and quaking mice. Presence and characterization of a labile ganglioside in alkaline solution].

In the adult Quaking mutant, there is an increase in some polysialogangliosides (GT1 and Gq) and a 50% decrease in BM1 content. Thus, the latter ganglioside, which is a constituent of mature myelin, could be linked to one of the late steps of the myelination process. A novel ganglioside ALG1, which appears during the postnatal development of brain, has been isolated and purified; it contains an alkali labile linkage and after alkaline treatment yields GT1b. Comparison between normal Mice and Quaking mutants does not show any significant quantitative differences, under our conditions. At the stage at which it appears, it could be linked to steps of brain maturation other than myelimation.

Animals↗
PubMed1978

Distribution of radioactivity in myelin lipids following subcutaneous injection of [14C]stearate.

Blood fatty acids are an important parameter for the synthesis of brain myelin as exogenous stearic acid is needed: after subcutaneous injection to 18-day-old mice this labelled stearic acid is transported into brain myelin and incorporated into its lipids. However the acid is partly metabolized in the brain by elongation (thus providing very long chain fatty acids, mainly lignoceric acid) or by degradation to acetate units (utilized for synthesis of medium chain fatty acids as palmitic acid, and cholesterol). These metabolites are further incorporated into myelin lipids. The myelin lipid radioactivity increases up to 3 days; most of the activity is found in phospholipids; their fatty acids are labelled in saturated as well as in polyunsaturated homologues but sphingolipids, especially cerebrosides, contain also large amounts of radioactivity (which is mainly found in very long chain fatty acids, almost all in lignoceric acid). The occurrence of unesterified fatty acids must be pointed out, these molecules unlike other lipids, are found in constant amount (expressed in radioactivity per mg myelin lipid).

Animals↗
PubMed1978

[Use of a zonal rotor for demonstrating that human myelin is formed by a continuum of particles of different densities].

Human myelin isolated from frozen brain consists of a continuum of particles as shown by sucrose continuous gradient (between 0,4 and 0,85 M) on zonal rotor. This was determined by measuring the O. D. at 260 and 280 millimicron, the protein concentration by Lowry method and sucrose concentration by polarimetry in 60 fractions. Most of the material is concentrated between 20-23% sucrose, the maximum being found at 21.5% (0.63 M). The fractions are dialyzed for 62 hrs. to remove the sucrose and the pellet obtained after centrifugation shows that the protein concentration increases from the ligher fraction to the heavier.

Brain Chemistry↗
PubMed1978

Incorporation of stearic acid into brain lipids in the developing brain: blood-brain relationships during development.

The blood-brain relationship for stearic acid varies during development. Subcutaneously injected [1-14C]-stearic acid is taken up by brain. Age-related changes in the metabolism of stearic acid have been determined in mouse brain from birth to maturity. Total lipid radioactivity reaches a maximum at 18 days of age and decreases afterwards until adulthood. However, specific radioactivity presents the highest value at 1 day of age and declines from then on. At any age, the injected acid is taken up and partly metabolized in the brain, either by elongation or by degradation in situ and resynthesis of new fatty acids; it is also desaturated, and the oleic acid thus formed is eventually elongated. The labeled stearic acid is incorporated into brain lipids with a different pattern according to the age of the injected animal.

Age Factors↗
PubMed1978

Is there a blood-brain relationship for saturated fatty acids during development?

Transport of subcutaneously injected [1-14C]-stearic acid through the blood-brain barrier is compared with endogenous biosynthesis (within the brain) during postnatal brain development in mice. The uptake is very important during glial cell multiplication and myelination; endogenous microsomal synthesis is most active during myelination, soluble de novo mechanism is prominent during cell multiplication (mitochondrial systems are not directly related to these events). A parallel is drawn between myelin fatty acids, microsomal synthesis and uptake from the blood.

Animals↗
PubMed1978

[Neurological disorders and perhexiline maleate therapy. Clinical study of 10 cases. Neuropathological, pharmacocinetic and biochemical studies (author's transl)].

Ten new cases of perhexiline induced peripheral neuropathies are reported. The authors emphasize the possible association of other neurological disorders: cerebellar symptoms in one case, complex tremor in two other cases, marked decrease of photomotor reflexes in one case and disgeusia in another one. The pharmacocinetic study of 4 cases revealed the presence of a low metabolism of the drug in one of them. Polymorphous inclusions have been seen in Schwann cell and endothelial cell cytoplasm in the three patients with electron microscopic study of the nerves. The pathological study of one case showed the demyelination of spinal cord posterior columns. In another case, who died from hepatic coma, the biochemical study of cerebral lipids revealed the low values of cerebrosides and sulfatides in cerebellum and cerebral white matter.

Cerebellar Diseases↗
PubMed1978

Circulating immune complexes in multiple sclerosis. Relation to clinical and biological parameters.

Circulating immune complexes were looked for on 38 clinically definite MS (multiple sclerosis) patients compared to 35 other neurological patients and 26 healthy subjects. 29% of the MS sera and 8.6% of the other neurological sera were positive, whereas none of the control sera were positive. These differences are significant. Clinical status was analysed as regards the age at onset, the duration and course of the disease, the disability of the patients and the treatment they received. CSF (cerebrospinal fluid) parameters studied were pleocytosis, concentration of total protein, electrophoresis. The results suggest that IC (immune complex) are more frequent during the first 10 years of the MS disease, in patients with blood-brain barrier damage and in patients without oligoclonal IgG.

Adult↗
PubMed1978

Microanalysis of brain lipids: multiple two-dimensional thin-layer chromatography.

The techniques described allow the quantitation of cholesterol, cerebrosides, sulfatides, ethanolamine phospholipids, phosphatidylcholine, -serine, -inositol, and gangliosides on 500 micrograms of lipid. Lipid extraction required sonication. Separation of the lipid classes was performed on TLC glass plates (10 x 10 cm) coated with silica gel HPTLC 60 F 254 Merck using one multiple two-dimensional chromatography. Most of the methods used for quantitation were standard methods that had been scaled down. The procedure was applied to study regional differences in the central nervous system, to analyze cell membranes or subcellular particles, or to analyze pathological biopsies in the central and peripheral nervous systems.

Animals↗
PubMed1977

Myelin consists of a continuum of particles of different density with varying lipid composition: major differences are found between normal mice and quaking mutants.

Mouse brain myelin consists of a continuum of particles of different densities, as shown by sucrose density gradient centrifugation. In normal animals most of the material (65 per cent) is concentrated between 0.6 and 0.7 M sucrose (the maximum being found at 0.66 M sucrose, corresponding to 23 per cent). The density differences among various myelin fractions are related to their protein/lipid ratios, as lighter fractions contain less protein and more lipid. Lipid analysis shows a decrease in the amount of every lipid from the lightest to the heaviest fraction: the light fraction is richer in phosphatidyl-ethanolamine, phosphatidyl-serine and cerebrosides. The distribution is highly abnormal in purified myelin from Quaking mutant ; very low quantities of myelin with normal density are found, but unexpected large amount of high density particles are found, possibly related to a "pre-myelin" material (oligodendrogial) processes which are not maturing into normal myelin).

Animals↗
PubMed1977

Very low arylsulfatase A and cerebroside sulfatase activities in leukocytes of healthy members of metachromatic leukodystrophy family.

Very low levels of arylsulfatase A (ASA) have been found in the leukocytes of healthy members of a metachromatic leukodystrophy (MLD) family. The cerebroside sulfate sulfatase (CSS) activities in the same individuals are about 10% of the control level. Arguments favoring a dominant mutation different from that of classical MLD are presented. This report reinforces the relationship between the two enzymatic activities.

Age Factors↗