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Biomedical subjects

N Baumann

Publications and source records attributed to N Baumann.

At least 181 records · Page 10Linked to original sources
PubMed1976

[Diagnosis of Fabry's disease].

On the basis of a study of 9 new cases of Fabry's disease (7 hemizygotes and 2 heterozygotes), the authors recall that the disease often presents as a painful syndrome of the extremities but its exact nature usually remains obscure for long periods. The association of such pain with angiokeratomas and the notion of a family history is highly suggestive of the disease. The biochemical possibilities in the diagnosis of the latter are described. All patients underwent transcutaneous renal biopsy. In the 7 hemizygotes and one of the heterozygotes, light microscopy revealed diffuse characteristic vacuolisation of the glomerular cells. In the other heterozygote, the glomerular lesions were very limited, seen only by electron microscopy.

Adolescent↗
PubMed1976

[Mouse brain gangliosides during development: demonstration of a new ganglioside].

The study of gangliosides as a function of age indicates that four of the main components GD1a (G3), GD1b (G2), GT1 (G1) and GQ (G0) are present at birth. They increase with age. On thin-layer chromatography, GD1a seems to be maximum at 18 days and GD1b continues to increase. GM1 increases also from birth to adult age. A new ganglioside has been detected in Mouse brain during its development. Not detected 5 days after birth, it is present at 18 days and in maximal quantity at adult age. This compound does not seem to be correlated to myelination process.

Age Factors↗
PubMed1976

[Biosynthesis of lignoceric acid in two organelles (mitochondria and microsomes) during the development of the brain in normal and pathologic (Quaking and Jimpy) mice].

In microsomes, biosynthesis of lignoceric acid from its direct precursor (behenyl-CoA) is largely increased during myelination. The peak is hardly detectable in Quaking; in Jimpy, the synthesis is nearly absent (3% of normal value); in the adult Quaking, the synthesis is normal. Mitochondria are capable of synthesizing lignoceric acid. This synthesis increases regularly during brain development and is normal in both mutants. Saturated fatty acid analysis is brain mitochondria shows that these organelles contain mainly palmitic and stearic acids. However, very long chains are also detectable. Thus it appears that mitochondria synthesize their own acids. Microsomes synthesize their own acids also and myelin fatty acids. There is no interplay between microsomal and mitochondrial metabolisms.

Age Factors↗
PubMed1976

[Study of the passage of stearic acid through blood-brain barrier and its incorporation in cerebral membranes (especially in myelin)].

Subcutaneously injected stearic acid is uptaken by brain and is further incorporated into membrane lipids (especially myelin). The uptake increases regularly up to 20 hrs. in total membranes as in myelin. In total membranes, there is a decrease between 20 and 24 hrs. followed by a recovery of the previous maximal activity. Moreover, the myelin activity increases up to 3 days, so far. Cerebrosides, isolated from both types of preparations, present an activity regularly increasing; but free fatty acids have a stable specific activity and a decreasing relative activity. The injected labelled stearic acid is directly incorporated into membrane lipids or is metabolized inside brain in longer chains (thus providing arachidic behenic and lignoceric acids) or in acetate units (utilized for synthesis of medium chain fatty acids such as palmitic acid).

Animals↗
PubMed1976

[Comparative biosynthesis of fatty acids, particularly lignoceric acid, in the kidney and brain of normal and "quaking" mice].

Palmityl-CoA elongation is normal in kidney and brain from Quaking mice. However elongation of stearyl-CoA and behenyl-CoA is disturbed in the mutant brain, but not in kidney. Moreove in both organs, the reaction products are the same in normal and Quaking animals. Thus the microsomal biosynthesis of very long chain fatty acid biosynthesis is normal in Quaking kidney and not in brain : the genetic control of elongating enzymes must be different according to the organ.

Animals↗
PubMed1976

Nervonic acid biosynthesis by erucyl-CoA elongation in normal and quaking mouse brain microsomes. Elongation of other unsaturated fatty acyl-CoAs (mono and poly-unsaturated).

Biosynthesis of nervonic acid by enzymatic elongation of erucyl-CoA has been studied in mouse brain microsomes. The substrate and cofactor requirements have been measured. Malonyl-CoA and reduced nicotine-adenine-dinucleotide phosphate are required, but not FMN, FAD or NADH. The effect of protein concentration, incubation time, ATP and CoA has been determined; the reaction products were checked by gas-liquid chromatography with automatic counting of the eluate. Very little activity was found in hydroxylated fatty acids. In the presence of phosphotransacetylase (which impedes the de novo microsomal system), the main reaction product was nervonic acid. It is concluded that nervonic acid is biosynthesised by elongation using a two-carbon unit from malonyl-CoA. The same enzyme biosynthesises saturated and mono-unsaturated very long chain fatty acids. The elongation capacity of "quaking" microsomes is reduced to 30% of the normal value with both erucyl-CoA and behenyl-CoA. Elongation of trans isomer (brassidyl-CoA) and poly-unsaturated homologue (clupanodonyl-CoA) was compared to elongation of erucyl-CoA in both normal and mutant mice. Both unsaturated acyl-CoAs are elongated under the same conditions as erucyl-CoA in brain: the poly-unsaturated acyl-CoA is elongated more actively than the mono-unsaturated acyl-CoA in the mutant.

Animals↗
PubMed1976

[Biosynthesis of fatty acids in mouse brain mitochondria in the presence of malonyl-CoA or acetyl-CoA].

Incorporation of malonyl-CoA or acetyl-CoA is studied in mouse brain mitochondrial fatty acids. Rupture of mitochondria is necessary ; Triton X-100 gives the best result. Other detergents or sonication are of lesser efficiency. Cofactor requirements have been studied : NADH and NADPH have been tested ; ATP increases biosynthesis and CoA causes an inhibition. Two systems of biosynthesis are involved : -- One is a de novo system using malonyl-CoA. Malonyl-CoA alone is incorporated and synthesizes mainly C16, indicating the existence of a malonly-CoA decarboxylase although elongation of short chain fatty acids cannot be excluded. Addition of acetyl-CoA increases the biosynthesis and palmityl-CoA when added causes an inhibition. -- The other system, using acetyl-CoA, elongates exogenous palmityl-CoA ; endogenous acyl-CoAs are not elongated by acetyl-CoA. All these results are confirmed by radiogas chromatographic studies of the reactions products.

Acetyl Coenzyme A↗
PubMed1975

Plasma galactocerebrosides in multiple sclerosis.

Plasma cerebrosides were examined in 12 cases of multiple sclerosis which were compared to normal controls and patients with cerebrovascular accidents. A screening was performed so as to select patients with levels above to normal by means of thin-layer chromatography of the lipid extract. Glucose seems to be the only hexose to be found normally in plasma cerebrosides. The presence of galactocerebrosides may be a biological test for demyelination, as their presence seems to be related to the evolutionary state of multiple sclerosis. In a severe cerebrovascular accident, galactocerebrosides were also found.

Adult↗
PubMed1975

Arylsulfatases isoenzymes in metachromatic leucodystrophy/detection of a new variant by electrophoresis improvement of quantitative assay.

Arylsulfatase A and B activities were assayed in leucocytes of 43 controls, 11 cases of Metachromatic Leucodystrophy and 7 parents or siblings of patients, using a new technique implying specific inhibitors for leucocyte enzymes. Heterozygotes can be determined, with a 50% value compared to the control, in variant B. Electrophoresis of leucocytes after enzymatic staining for arylsulfatase, is a complementary technique which allowed the detection of a new form of metachromatic leucodystrophy.

Adult↗
PubMed1975

Metachromatic leukodystrophy. Ultrastructural and enzymatic study of a case of variant O form.

A variant of metachromatic leukodystrophy (MLD), Austin disease, is characterized by a multiple isozyme deficiency of arylsulfatase. A 3 1/2-year-old girl with progressive mental and physical deterioration had decreased activities of arylsulfatases A and B in the leukocytes, shown by acylamide gel electrophoresis. Under the electron microscope, biopsy specimens of the brain and the peripheral nerve showed lamellar structures with socalled zebra bodies in the cytoplasmic processes of glial cells, granulo-membranous inclusions with fingerprint configurations in neurons, and myelinlike material in Schwann cells. Results from our study suggest an intricate nature of this dysmetabolic disorder, which shows ultrastructural changes usually seen in classic MLD, a deficiency of arylsulfatase A only, concomitant with those seen in mucopolysaccharidoses such as Hurler and Sanfilippo syndromes.

Cerebroside-Sulfatase↗
PubMed1975

[Substrates and products of fatty acid elongation in mouse brain microsomes].

In brain microsomes, palmitate and stearate elongation involve a membrane lipid-bound substrate. After elongation by malonyl-CoA, acyl-products are partially bound to proteins. Acyl-proteins are not found when endogenous fatty acid elongation takes place. In the dysmyelinating Quaking mouse mutants, "stearyl-membrane" substrate formation is normal; thus, the deficiency observed in very long chain fatty acid formation is not due to a lack in substrate formation.

Animals↗