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At least 379 records · Page 21Linked to original sources
PubMed1977

Polydispersity of cartilage proteoglycans. Structural variations with size and buoyant density of the molecules.

Proteoglycan monomers were subfractionated according to buoyant density by dissociative CsCl density gradient centrifugation. It was shown that with decreasing buoyant density of the proteoglycan subfraction: (a) the average sizes of the molecules decreased (shown by Sepharose 2B chromatography); (b) the relative content of chondroitin sulfate decreased; (c) the relative content of protein increased; (d) the relative proportion of the amino acids glycine and serine, which occur close to the chondroitin sulfate-peptide linkage, decreased; (e) the relative proportion of the hyaluronic acid-binding region released by treatment of proteoglycans with cyanogen bromide increased; (f) the relative content of the keratan sulfate-enriched region increased. The data indicate that proteoglycans contain a nonvariable hyaluronic acid-binding region, a keratan sulfate-enriched region and a chondroitin sulfate-enriched region of variable size. It is concluded that proteoglycans vary in size mainly because of variations in the size of the chondroitin sulfate-enriched region. Additional data were obtained using subfractions of proteoglycan monomers isolated according to size differences by using Sepharose 2B chromatography. The Kav values of the subfractions on Sepharose 2B ranged from 0 to 0.54. Analyses of these subfractions showed the same variations with size of the content of chondroitin sulfate, protein, amino acids, hyaluronic acid-binding region, and keratan sulfate-enriched region, as was shown for the subfractions isolated at different buoyant densities in the dissociative gradient.

Amino Acids↗
PubMedDate not supplied

Structural variations between pleural and peritoneal mesotheliomas produced in rats by the injection of crocidolite asbestos.

The author studies the ultrastructure of pleural and peritoneal mesotheliomas caused in the rat by the intra-pleural or intra-peritoneal injection of 25 mg of crocidolite. In the peritoneum the tumour is made up chiefly of "connective" type tissue with rare "epithelial" cells. In the pleura, the "epithelial" cells predominate, constituting vast vegetating "papillomatous" zones or "adenomatous" territories. The author recalls Willis' concept, and feels that mesothelial tumours in the rat, caused by asbestos, represent one aspect of the family of mesenchymatous tumours, with their ability to behave differently according to their site.

Adenoma↗
PubMed2005

Variations of structure and appearance of the oral mucosa.

Among the most important factors in a thorough clinical examination is the dentist's ability to recognize and make distinctions among normal oral structures, variations of normal structures, and pathologic entities. The practitioner's diagnostic acumen is essential to this process and is a skill gained and refined by clinical experience and continuing education. In this introductory article, the authors describe normal entities, anomalies, and benign soft tissue lesions of interest to the clinician. For presentation, these structures are organized according to their location within the oral cavity.

Exostoses↗
PubMed2000

The streptococcal superantigen SMEZ exhibits wide allelic variation, mosaic structure, and significant antigenic variation.

The frequencies of the newly identified streptococcal superantigen genes smez, spe-g, and spe-h were determined in a panel of 103 clinical isolates collected between 1976 and 1998 at various locations throughout New Zealand. smez and spe-g were found in every group A Streptococcus (GAS) isolate, suggesting a chromosomal location. The spe-h gene was found in only 24% of the GAS isolates and is probably located on a mobile DNA element. The smez gene displays extensive allelic variation and appears to be in linkage equilibrium with the M/emm type. 22 novel smez alleles were identified from 21 different M/emm types in addition to the already reported alleles smez and smez-2 with sequence identities between 94. 5 and 99.9%. Three alleles are nonfunctional due to a single base pair deletion. The remaining 21 alleles encode distinct SMEZ variants. The mosaic structure of the smez gene suggests that this polymorphism has arisen from homologous recombination events rather than random point mutation. The recently resolved SMEZ-2 crystal structure shows that the polymorphic residues are mainly surface exposed and scattered over the entire protein. The allelic variation did not affect either Vbeta specificity or potency, but did result in significant antigenic differences. Neutralizing antibody responses of individual human sera against different SMEZ variants varied significantly. 98% of sera completely neutralized SMEZ-1, but only 85% neutralized SMEZ-2, a very potent variant that has not yet been found in any New Zealand isolate. SMEZ-specific Vbeta8 activity was found in culture supernatants of 66% of the GAS isolates, indicating a potential base for the development of a SMEZ targeting vaccine.

Alleles↗