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Until the early l940's the field or protein-carbohydrate complexes was largely neglected by chemists. This fact is not surprising when one considers that typical examples of substances containing these complexes are saliva, serum, gastric mucin or better still frog spawn mucin and jellyfish protoplasm. Adequate yields of homogenous materiel, from these sources, were difficult to obtain partly because of their high degree or hydration. [...]

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Histochemical treatments specific for hyaluronic acid, chondroitin sulphate A/C, chondroitin sulphate B, and heparin, which are biological compounds classed as acid mucopolysaccharides, were applied to a series of Pacific great skate (Raja binoculata) embryos in order to characterize histochemically the acid mucopolysaccharides present in the embryos and to study the events leading to the situation of acid mucopolysaccharides localization in the adult. Embryonic stages examined ranged from early cleavage to immediate prehatching. A progression was observed from; 1. intracellular neutral polysaccharides in cleaving stages through, 2. a combination of extracellular neutral polysaccharides and weakly acidic acid mucopolysaccharides (hyaluronic acid) associated with cell processes in neurulating stages to, 3. extracellular strongly acidic sulphated acid mucopolysaccharides (chondroitin sulphates) in later stages, particularly in areas of cartilage development. In neurulating embryos hyaluronic acid appeared in considerable quantity between some adjacent tissue layers in a smooth layer form suggestive of some developmental significance for this compound. Hyaluronic acid also occurred in a similar form in lesser quantity in post neurulae (17-18 mm. embryos) in close association with developing gut and mesonephros. Results of histological tests in immediate prehatching embryos agreed with previously reported biochemical analyses of shark skins and cartilages i.e. chondroitin sulphate B occurred primarily in the skin and chondroitin sulphate A/c were a major component of the cartilage matrix. / Science, Faculty of / Zoology, Department of / Graduate

Herniation of the intervertebral disc is a pathological condition characterized by protrusion of the tissue posterio-laterally, often impinging on the spinal chord or nerve roots. The disease is accompanied by a reduction in the average molecular weight and viscosity of the disc proteoglycans, in excess of that which normally occurs with increasing age. The proteoglycans of disc however have not been examined in terms of the modern concepts of cartilage matrix structure. Bovine nasal cartilage, has been shown to contain proteoglycan aggregates, trapped in the intersticess of a collagen network, which can be dissociated with 4M guanidine hydrochloride into diffusible proteoglycan subunits and a multicomponent "linking" fraction. A similar system was thought to occur in the intervertebral disc. It seemed possible that, if such a system was present in the disc, the reduction in the molecular weight and viscosity of the proteoglycans with increasing age and herniation could be due to a decrease in proteoglycan aggregation. The present study showed that proteoglycan aggregates similar to those of bovine nasal cartilage are found in the human intervertebral disc, but that they only represent 5% of the total proteoglycans in the tissue. In contrast, bovine nasal cartilage contained 70% of the proteoglycans in the aggregated form. A novel modification of the extraction procedure was devised by which it was possible to assess the degree of proteoglycan aggregation. Sequential extraction of the tissue with a weak and strong electrolyte (0.4 M and 4M guanidine hydrochloride) selectively removed non-aggregated and aggregated proteoglycans respectively. This procedure provides a new and rapid method for assessing the degree of proteoglycan aggregation in a variety of connective tissues. The small proportion of aggregate in the disc was almost exclusively located in the annulus fibrosus. Re-aggregation studies suggested that both disc and cartilage contain two proteoglycans, only one of which is capable of forming aggregates. Examination of the proteoglycans in a limited number of discs suggested that the degree of aggregation did not change with increasing age. Since, in addition, aggregates represent only a small proportion of the disc proteoglycans, it appeared unlikely that a decrease in the degree of aggregation could account for the decrease in molecular weight and viscosity of the disc proteoglycans observed with increasing age and/or degenerative disc disease. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate