| 1. |
- Lohmander, Stefan, et al.
(author)
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Chemical and metabolic heterogeneity of chondroitin sulfate and keratan sulfate in guinea pig cartilage and nucleus pulposus
- 1973
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In: Biochimica et Biophysica Acta. General Subjects. - : Elsevier BV. - 0304-4165. ; 304:2, s. 430-448
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Journal article (peer-reviewed)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.
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| 2. |
- Lohmander, Stefan, et al.
(author)
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In vitro studies on the effect of in vivo zinc deficiency on the formation of glycos-aminoglycans in rat costal cartilage
- 1972
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In: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 30:1, s. 89-96
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Journal article (peer-reviewed)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.
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| 3. |
- Lohmander, Stefan
(author)
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Ion exchange chromatography of glucosamine and galactosamine in microgram amounts with quantitative determination and specific radioactivity assay
- 1972
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In: Biochimica et Biophysica Acta. General Subjects. - : Elsevier BV. - 0304-4165. ; 264:3, s. 411-417
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Journal article (peer-reviewed)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.
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| 4. |
- Lohmander, Stefan, et al.
(author)
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Proteoglycans of mineralizing rib and epiphyseal cartilage
- 1975
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In: Biochimica et Biophysica Acta. General Subjects. - : Elsevier BV. - 0304-4165. ; 404:1, s. 93-109
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Journal article (peer-reviewed)abstract
- Rib cartilage from growing guinea pigs and epiphyseal cartilage from Beagle puppie were separated into three fractions, representing non-mineralized, low mineralized, and high mineralized, tissue, by centrifuging finely ground material in acetone/bromoform density gradients. Following extraction under dissociative conditions, the proteoglycans were fractionated by density gradient ultracentrifugation under associative and dissociative conditions. With the onset of mineralization, the cartilage lost approximately half its content of proteoglycans. The proteoglycans remaining in the calcified cartilage differed in composition and in size from those of nonmineralized tissue. With the increased mineral content of the tissues the ratios of protein to polysaccharide, of chondroitin sulfate to keratan sulfate, and of 4-sulfated to 6-sulfated chondroitin sulfate increased in the proteoglycan fraction. Furthermore, gel chromatograms indicated decreased proportions of very high molecular weight proteoglycans, in mineralized tissue.
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| 5. |
- Lohmander, Stefan
(author)
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Turnover of proteoglycans in guinea pig costal cartilage
- 1977
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In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 180:1, s. 93-101
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Journal article (peer-reviewed)abstract
- The turnover in vivo of proteoglycans of guinea pig costal cartilage was investigated using Na2 35SO4 as precursor. Proteoglycans were extracted with guanidine · HCl, at both low and high ionic strength, and purified and fractionated by ultracentrifugation in CsCl gradients under associative and dissociative conditions. The results suggest that the sulfate is incorporated into macromolecules of at least two major metabolic pools with half-lives of about 3 days and about 60-70 days, respectively. Molecules with a fast turnover were enriched in the low ionic strength extracts and in fractions containing small, nonaggregated proteoglycans. No substantial evidence was found for a precursor-product relationship between different fractions.
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| 6. |
- Madsen, Kjell, et al.
(author)
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Production of cartilage-typic proteoglycans in cultures of chondrocytes from elastic cartilage
- 1979
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In: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861. ; 196:1, s. 192-198
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Journal article (peer-reviewed)abstract
- Chondrocytes from rabbit ear cartilage were isolated and cultured as monolayers in Ham's F-12 medium. The proteoglycans synthesized by short-term cultures formed a high proportion of aggregates and contained chrondroitin-4- and -6-sulfate in a 2:1 proportion. Dermatan sulfate was not present. The average molecular weight of the chondroitin sulfate was about 20,000. Keratan sulfate with an average molecular weight of about 6000 could be isolated from the proteoglycan monomers. Rabbit ear chondrocytes in culture thus produced proteoglycans comparable to those isolated from hyaline cartilage. Culture for longer periods and plating at lower density caused a decrease in the proportion of aggregated proteoglycans. Primary cultures continued to synthesize aggregated proteoglycans for at least 2 weeks, while subdivision of the cultures caused a shift toward the production of small-sized "ubiquitous proteoglycans." The synthesis of proteoglycan aggregates could, however, be partly restored by transfer of the monolayer cells to a suspension culture.
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| 7. |
- Madsen, Kjell, et al.
(author)
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Proteoglycans synthesized by fetal Guinea pig chondrocytes in culture
- 1978
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In: Connective Tissue Research. - : Informa UK Limited. - 0300-8207 .- 1607-8438. ; 5:4, s. 205-210
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Journal article (peer-reviewed)abstract
- Short term cultures were carried out with chondrocytes and tissue fragments from fetal guinea pig epiphyseal cartilage. Proteoglycans were isolated from these cultures and their properties were compared with those of pro-teoglycans from adult hyaline cartilage. It was concluded that the proteoglycans synthesized in culture were essentially similar to those present in cartilage matrix in vivo. The authors therefore suggest that fetal guinea pig chondrocytes cultured in monolayer or as aggregates in suspension constitute a useful system for the study of synthesis and secretion of proteoglycans.
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| 8. |
- Thyberg, Johan, et al.
(author)
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Electron microscopic demonstration of proteoglycans in guinea pig epiphyseal cartilage
- 1973
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In: Journal of Ultrastructure Research. - 0022-5320. ; 45:5-6, s. 407-427
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Journal article (peer-reviewed)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.
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