| 1. |
- Lohmander, Stefan, et al.
(författare)
-
Chemical and metabolic heterogeneity of chondroitin sulfate and keratan sulfate in guinea pig cartilage and nucleus pulposus
- 1973
-
Ingår i: Biochimica et Biophysica Acta. General Subjects. - : Elsevier BV. - 0304-4165. ; 304:2, s. 430-448
-
Tidskriftsartikel (refereegranskat)abstract
- Chondroitin sulfate and keratan sulfate in guinea pig costal cartilage, nasal septum cartilage and nucleus pulposus were separated and fractionated by chromatography on CPC-cellulose, ECTEOLA-cellulose and Sephadex G-200 columns. Characterization of the chondroitin sulfates included determination of molecular weight and of the number, and position, of sulfate groups of the disaccharide units. Distinct chemical differences were found between the total fractions of chondroitin sulfate from the three tissues. Within the total fractions a marked heterogeneity was also apparent. The turnover of the two glycosaminoglycans was studied by using radioactive sulfate as precursor. The guinea pigs were killed at eight intervals, ranging from 30 min to 40 days after injection of the isotope. Total fractions of chondroitin sulfate from rib, nasal septum and nucleus pulposus showed half-lives of about 80, 40 and 30 days, respectively. In addition, the existence of a second metabolic component with a faster turnover (half-life about 3 days) was indicated in chondroitin sulfate from all three tissues. Similarly, keratan sulfate from the rib contained a 'slow' component with a half-life of about 90 days and a 'fast' component with a half-life of 4 days. For keratan sulfate from nucleus pulposus only a single component was demonstrable; it had a half-life of about 30 days. Within the total fractions of both chondroitin sulfate and keratan sulfate from the three tissues studied, a considerable degree of metabolic heterogeneity was apparent between, and within, subfractions of differing molecular weight.
|
|
| 2. |
- Lohmander, Stefan, et al.
(författare)
-
In vitro studies on the effect of in vivo zinc deficiency on the formation of glycos-aminoglycans in rat costal cartilage
- 1972
-
Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 30:1, s. 89-96
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of in vivo zinc deficiency and restricted food intake, on the in vitro synthesis of glycosaminoglycans of rib cartilage were studied in the rat. 35S-sulfate and 14C-glucosamine were used as precursors. The glycosaminoglycans were separated on microcolumns and specific radioactivities determined for the different fractions. Chemical analyses showed that zinc deficiency or reduced food intake did not cause any qualitative or quantitative changes in the glycosaminoglycans. The radioassays indicated that zinc deficiency and reduced food intake, alone or combined, caused a somewhat lowered synthetic rate of chondroitin sulfate. In the discussion it is underlined that it seems difficult to determine conclusively the importance of zinc for the formation of the mucopolysaccharides through further in vivo deficiency studies, because of the difficulties to control and evaluate the inanition factor.
|
|
| 3. |
- Lohmander, Stefan
(författare)
-
Ion exchange chromatography of glucosamine and galactosamine in microgram amounts with quantitative determination and specific radioactivity assay
- 1972
-
Ingår i: Biochimica et Biophysica Acta. General Subjects. - : Elsevier BV. - 0304-4165. ; 264:3, s. 411-417
-
Tidskriftsartikel (refereegranskat)abstract
- A rapid method for the separation and quantitative determination, including radioassay, of glucosamine and galactosamine in microgram amounts is described. It is based upon the use of a column of Aminex A-5 ion exchange resin eluted with a phosphate buffer at pH 7.00 and 60 °C. From each fraction half the volume is used for a scaled down Elson-Morgan procedure and other half for liquid scintillation counting. Amounts of about 0.01-1 μmole of hexosamine may be separated and determined.
|
|
| 4. |
- Thyberg, Johan, et al.
(författare)
-
Electron microscopic demonstration of proteoglycans in guinea pig epiphyseal cartilage
- 1973
-
Ingår i: Journal of Ultrastructure Research. - 0022-5320. ; 45:5-6, s. 407-427
-
Tidskriftsartikel (refereegranskat)abstract
- Guinea pig epiphyseal cartilage was studied ultrastructurally after staining with ruthenium red or Alcian Blue. Extracellularly, the matrix granules were positively stained with both dyes, whereas no apparent staining of the collagen fibrils occurred. Intracellularly, a positive ruthenium red staining of the Golgi vacuole granules was observed. No Alcian Blue staining of the content of the vacuoles was detected. The fresh, untreated cartilage contained about 1.3% hexosamine on a dry weight basis. About three-fourths thereof represented chondroitin sulfate, the remaining part keratan sulfate and glycoproteins. After digestion of thin cartilage slices with hyaluronidase or chondroitinase ABC the chondroitin sulfate content was less than 50% of that in the buffer-incubated controls. Concomitantly, the matrix granules were reduced in size and number or completely absent. Papain digestion removed more than 90% of the chondroitin sulfate and all matrix granules. From these findings it was concluded that the matrix granules contain proteoglycans. Moreover, it seemed reasonable to assume that the Golgi vacuole granules, at least in part, represent intracellular proteoglycans. Signs of secretion of these granules by exocytosis were occasionally observed.
|
|
| 5. |
|
|
| 6. |
- Jonsson, Gösta, et al.
(författare)
-
6-Hydroxydopamine induced degeneration of noradrenaline neurons in the scorbutic guinea-pig
- 1974
-
Ingår i: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952. ; 23:18, s. 2585-2593
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of the neurotoxic compound 6-hydroxydopamine and its immediate precursor 6-hydroxy-DOPA on noradrenaline uptake and storage in central and peripheral catecholamine neurons of scorbutic and normal guinea-pigs has been investigated. Endogenous noradrenaline in heart and brain as well as the in vitro uptake-accumulation of 3H-noradrenaline in iris and slices of heart and brain were not significantly changed in scorbutic animals. The in vitro formation of 3H-noradrenaline from 3H-dopamine was markedly reduced in heart slices of scorbutic guinea-pigs, due to ascorbic acid being a co-factor for dopamine-β-hydroxylase. There was an increased depletion of brain noradrenaline following tyrosine hydroxylase inhibition produced by α-methyl-p-tyrosine methylester in scorbutic animals, indicating an increased NA turnover. Administration of 6-hydroxydopamine or 6-hydroxy-DOPA resulted in a similar reduction of endogenous NA in brain and heart as well as of the in vitro uptake of 3H-noradrenaline in iris, and slices from heart, cerebral cortex and hypothalamus in scorbutic and control guinea-pigs. These results are discussed in view of current hypotheses on mechanisms involved in the neurotoxic action of 6-hydroxydopamine on catecholamine neurons.
|
|
