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Biomedical subjects

N Baumann

Publications and source records attributed to N Baumann.

At least 145 records · Page 8Linked to original sources
PubMed1980

Arylsulfatases A and B in leukocytes: a comparative statistical study of late infantile and juvenile forms of metachromatic leukodystrophy and controls.

We report a statistical study on the level of aryl-sulfatases A and B in leukocytes of 106 controls, 19 cases of metachromatic leukodystrophy (MLD) infantile and juvenile forms and 25 obligate heterozygotes for MLD. Arylsulfatase A has been found to be similarly deficient in patients of the two forms. Half of the mean of the controls have been found in both types for heterozygotes. Arylsulfatase B (ASB) is slightly higher than normal in late infantile MLD although it is not statistically significant. In the 5 cases of the juvenile forms that were examined, ASB was found to be significantly reduced. This enzyme may play a role in relation to the onset of the disease.

Adolescent↗
PubMed1980

[Biochemical and pharmacological approach to the functional disorders observed in demyelination mutants (GABAergic and noradrenergic systems)].

The abnormal behavior observed in diseases of myelin remains unexplained. Mutations in the mouse in which the main phenotypic expression involves myelination is a useful tool. As tonic seizures are observed, an electrophysiological, pharmacological and biochemical study was performed. The convulsions seem to be linked mainly to an alteration of the alpha-adrenergic system. The GABA-ergic system is also modified. The relations between these observations and the defect of myelination remain to be elucidated.

Animals↗
PubMed1980

[Sulfatide: a multifunctional glycolipid constituent of biological membranes].

Sulfogalactosylceramide (or sulfatide) has been localized in the central nervous system by indirect immunofluorescence. This glycosphingolipid belongs essentially to the myelinated areas. Nevertheless, it has also been found in ependymal cells, subpial processes and, in the cerebellum, in the Bergmann fibers. In the brain areas, known to be enriched in opiate receptors, some cells and nerve terminals are also sulfatide positive. In this latter localization, opiates were shown to selectively inhibit binding of the antisulfatide antibodies. We have also shown that antisulfatide inhibited, in vitro, the stereo-specific binding of narcotic drugs and that they antagonized the in vivo effects of morphine and beta-endorphin.

Animals↗
PubMed1980

[Elongation of fatty acids in the nervous system].

Brain contains two families of fatty acids, their localization and thus their function are different. Polyunsaturated fatty acids are mainly found in grey matter and are related to neuronal activity: C20:4 and C22:6 (omega 6 and omega 3, respectively) are quantitatively very important; it is not known if their synthesis occurs in situ (from C18 - essential fatty acids only in trace amount in brain) or if they originate from an extracerebral pool. Saturated fatty acids are mainly found in myelin. Saturated fatty acid biosynthesis occurs in three subcellular comportments: cytosol, mitochondria and endoplasmic reticulum: the same enzymes elongate saturated as well as monounsaturated homologues. In contrast the synthesis of polyunsaturated fatty acids is hardly known: elongation-desaturation mechanisms shown in the liver are also possibly present in the brain. The regulation of fatty acid biosynthesis is studied at two levels: --level of metabolic pathways: occurence of elongation is related to cell differciation, lipidic receptors being also involved; --level of enzymatic activities: elongation is the result of successive reaction and regulation is acting on condensing enzyme for saturated fatty acid biosynthesis, this enzyme determines kinetics of the overall chain lengthening and the chain length specificity.

Animals↗
PubMed1979

[Electron microscopic and neurochemical study of Alexander's disease (author's transl)].

The authors report the results of a cerebral and of a neuromuscular biopsies and of the autopsy findings in another infantile case of Alexander's disease in a girl. They review the 17 previously reported cases of this disease and the various etiopathogenic hypotheses mentioned. The presence of numerous, sometimes abnormal enlarged mitochondria and of abundant membranous cytoplasmic bodies in the astrocytic cytoplasm seems to be unreported elsewhere. Peripheral nerve changes are mentioned for the first time.

Astrocytes↗
PubMed1979

Analysis of the major lipid classes in human peripheral nerve biopsies. Age group differences and abnormalities of ganglioside level in perhexiline maleate therapy.

We report here the results of a simple and reproducible technique which can be used in semi-routine analysis of peripheral nerve biopsy specimens, so as to have a quantitative analysis of the major lipid classes, i.e. cholesterol, cerebrosides, ethanolamine phospholipids, phosphatidyl-choline, phosphatidyl-serine + phosphatidylinositol, sphingomyelin and gangliosides. Glycolipid hexoses, cholesterol and total phospholipids have been compared in different age groups. Although all lipid classes increased from the younger to the older age group, the molar ratio of cholesterol to phospholipid differed less than the glycolipid to phospholipid ratio. Both increased significantly, even between age group 10--16 and older patients (36, 54, 61, 68, 72 and 73 years old). Although individual variations in lipid content are noteworthy, it must be emphasized that evolution with age of the lipid composition must be taken into account. Furthermore, this study confirms and extends earlier findings of increased ganglioside levels in some cases of peripheral neuropathies observed during perhexiline maleate therapy where characteristic lipid-like polymorphous inclusions have been demonstrated.

Adolescent↗
PubMed1979

In vivo incorporation of exogenous [1-14C]stearic acid into neurons and astrocytes.

Exogenous stearic acid is needed to synthesize the membranes of neurons and astrocytes. Subcutaneously injected [1-14C]acid is taken up through the 'blood brain barrier' and incorporated into lipids of both cell types, the specific radioactivity being higher in astrocytes as compared to neurons (2200 and 800 cpm/mg proteins, respectively), 20 h after injection. Phospholipids contain high amount of radioactivity (80% in astrocytes, 65% in neurons); glycosphingolipids contain low quantities of label in the two cell types. The injected acid is partly metabolized in the brain by elongation and desaturation (thus providing very long chains, saturated mono-unsaturated and poly-unsaturated); it is also partly degraded into acetate units (utilized for synthesis of palmitic acid).

Animals↗
PubMed1979

Absence of the major dense line in myelin of the mutant mouse "shiverer".

The myelin of the central nervous system (CNS) of the mutant mouse Shiverer is characterized by the absence of the major dense line (MDL). The intraperiod line, as seen in conventional electron micrographs and in freeze-fractured replicas, appears normal. Peripheral myelin, as seen in ventral and dorsal roots of spinal cord, is unaffected by the mutation. During the period of active myelination, the cytoplasm of most oligodendrocytes (ODs) is packed with electron-lucent vacuoles in continuity with the Golgi apparatus and with bundles of microtubules. It is concluded that a metabolic pathway possibly involving the Golgi apparatus, and contributing to the formation of the MDL is selectively affected in this mutant.

Animals↗
PubMed1979

Immunochemical studies of myelin basic protein in shiverer mouse devoid of major dense line of myelin.

The myelin-deficient mutant Shiverer (Shi/Shi) lacks basic protein (MBP) in the myelin of its central nervous system (CNS). Less than 3% of the normal content in MBP is present in a brain extract of Shi/Shi as determined by radioimmunoassay. Indirect immunofluorescence is negative when using specific anti-MBP serum. The importance of Shi/Shi (as compared to other hypomelinating mutants) stems from the specificity of this genetic lesion, i.e. the lack of basic protein.

Animals↗
PubMed1979

GFA and S 100 protein levels as an index for malignancy in human gliomas and neurinomas.

Human glia-specific proteins S 100 and GFA were quantitated by use of a rocket immunoelectrophoresis technique with monospecific antisera. No relation was found between the S 100 protein content of an astrocytoma and its degree of neoplasia. However, the lower the GFA protein content of the astrocytoma, the more malignant it was. Similarly, the more malignant a neurinoma was, the lower was its S 100 protein content. Therefore, the levels of these proteins might be used as indexes of neoplastic dedifferentiation.

Astrocytoma↗
PubMed1979

Infantile form of so-called neuronal ceroid lipofuscinosis: lipid biochemical studies, fatty acid analysis of cerebroside sulfatides and sphingomyelin, myelin density profile and lipid composition.

The biochemical analysis of a case of infantile neuronal ceroid lipofuscinosis, as determined by clinical and neuropathological findings, is presented. A diminished amount of solids is found, the amount of lipids is 30% of the normal as expressed in lyophilized tissue. The yield of myelin isolated by the density gradient is 1.8% of the normal. Phospholipid patterns show a reduction in ethanolamine phosphoglyceride, N-acetylneuraminic acid is extremely low and sphingolipids are largely reduced, cerebrosides being most affected (2.5% of the normal). In cerebrosides and sulfatides the decrease in very long chain fatty acids is important, but the deficiency in any type (including hydroxy compounds) is not too dramatic. According to the aspect under electron microscopy, the density profile, and the biochemical composition of the subfractions, isolated myelin is close to normal. The loss of the myelin sheath appears to reflect a Wallerian degeneration in the CNS: myelin loss is a secondary effect. This disease, from a biochemical point of view, seems to be the ideal control for leukodystrophies.

Atrophy↗
PubMed1979

[Mini-review on the properties of glial cells of the central nervous system (author's transl)].

During the past 15 years, increasing studies have been devoted to glial cells, i.e. oligodendrocytes, astrocytes and microglial cells of the central nervous system. Although most of their functions remain mysterious, the concept of intracellular interactions between neurons and neuroglia becomes more and more substantiated. This review describes some aspects of phylogeny of glia, recent technical approaches to the study of these cells, their major morphological and biochemical characteristics, their maturation as well as their pathology.

Animals↗
PubMed1979

Bismuth intoxication: bismuth level in pig brain lipids and in subcellular fractions.

Experimental intoxications of pigs were performed. It seems to be confirmed that bismuth crosses the blood-brain barrier. An organic derivative, trivinyl-bismuth, is more active than the inorganic salt of bismuth. In the brain, bismuth is preferentially found in synaptosomes. Bismuth is found in brain lipids of control pigs at very low levels. In intoxicated pigs, the level of bismuth is increased mainly in cerebellum and then in thalamus. Bismuth is partly associated to lipids. There is not a correlation between the level of bismuth in blood and in brain lipids. However, in the trivinyl intoxicated pig, a high level of blood bismuth is concomittant to a high level of brain lipid bismuth. The high content of this metal in cerebellum lipid extract may be of functional significance.

Animals↗
PubMed1979

[Extraction of plasma lipids preserving antigenic properties of proteins and allowing quantitation of gangliosides by neuraminic acid determination (author's transl)].

A technique described by Cham and Knowles allows the extraction of plasma phospholipides, triglycerides, cholesterol and free fatty acids without denaturing the proteins. The method has been slightly modified by us. Under our conditions, the yield of lipid extraction is comparable to the method of Folch. It has the advantage of not extracting mineral phosphorous and blood glucose. Thus gangliosides can be also easily determined. We confirmed by immunoelectrophoresis that the antigenic properties of plasmatic proteins remain after lipid extraction.

Blood Proteins↗