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Biomedical subjects

B A Fraser

Publications and source records attributed to B A Fraser.

47 records · Page 3Linked to original sources
PubMed1978

The effect of retinoic acid on chondrogenesis in the fetal hamster tibia in vivo.

Chondrogenesis in the fetal hamster tibia was examined 24, 36 and 48 h after maternal administration of retinoic acid at a known teratogenic dose (80 mg/kg) on day 10 of gestation. Twenty-four hours after treatment the tibial chondroblasts were more closely packed with less intervening fibrillar or granular matrix than in the controls. By 36 h post treatment, an intercellular matrix containing wide clumped fibrils unassociated with matrix granules had begun to accumulate, while the condroblasts had a relatively poorly developed Golgi apparatus and smooth, non-scalloped cell outlines. Cells frequently maintained contact chondroblasts appeared similar to controls of the same age. It is suggested that the paucity and abnormality of the extracellular matrix prevents the chondroblasts from assuming their normal spatial relations with each other, resulting in a small skeletal blastema.

Abnormalities, Drug-Induced↗
PubMed1978

Rabbit latent group a allotypes: characterization and relationship to nominal group a allotypic specificities.

Latent group a allotypes were detected with a sensitive radioimmune inhibition assay. Sera, IgG preparations, and antibody fractions containing these allotypes inhibited the binding of insolubilized allotypic antisera to various radiolabeled antigens including IgG pools, homogeneous antibodies, and, in the case of a3, a VH fragment from a3/b4 IgG. Several different group a antiallotypic sera were used in the assays and all gave similar results. Comparison of inhibition curves for nominal and latent allotypes indicated that the full spectrum of allotypic subspecificities may be expressed in latent allotypes. Hemagglutination studies carried out with five sera containing high levels of latent allotypes confirmed the results obtained with the radioimmunoassay and indicated that inhibition values did not, at least in four of the five samples studied, reflect the presence of antiallotype antibodies.

Animals↗
PubMed1977

A disaccharide hapten from streptococcal group C carbohydrate that cross-reacts with the Forssman glycolipid.

A disaccharide hapten was isolated in approximately 20% yield from an acid hydrolysate of the streptococcal Group C carbohydrate. This disaccharide was assigned the structure 3-0-alpha-N-acetylgalactosaminosyl-N-acetylgalactosamine on the basis of chemical and immunochemical data. The ability of the hapten to inhibit completely the binding between Group C carbohydrate and most Group C antibodies indicated that this disaccharide is the immunodominant feature of the Group C carbohydrate. Fractionation of antisera on an alpha-N-acetylgalactosamine immunoadsorbent column yielded several populations of anti-Group C antibodies. The reaction between labeled Group C carbohydrate and antibodies which strongly bound the immunoadsorbent column was 50% inhibitable by the disaccharide hapten when the hapten was added in approximately 15-fold excess (w/w) of the labeled antigen. On the other hand, the binding of those antibodies which did not bind to the immunoadsorbent column was poorly inhibited under these conditions. The Forssman glycosphingolipid, which has a common terminal digalactosamine unit, was shown to likewise inhibit Group C carbohydrate binding reactions.

Acetylgalactosamine↗
PubMed1975

Nonallelic behavior of rabbit variable-region allotypes.

Group a allotypes not detected by qualitative typing or anticipated from breeding data (latent allotypes) were detected at low levels in 50% of normal rabbit sera tested. The latent allotypes, which were serologically identical to allotypes of pooled IgG, were detected in sera from rabbits with all possible combinations of group a allotypes and their occurrence in individual rabbits was transitory and sporadic. These findings give reason to question the assumption that the synthesis of immunoglobulin allotypes is directed by allelic structural genes.

Animals↗
PubMedDate not supplied

Chemical structure of and immune response to polysaccharides of Streptococcus pneumoniae.

By use of rabbit antisera, extensive cross-reactions were demonstrated among pneumococcal (Danish) types 6A and 6B, types 9N, 9A, 9L, and 9V, and types 19F and 19A. The structural similarity of the group 6 polysaccharides was associated with extensive immunogenicity in humans. In contrast, immunization of humans with type 19F or 19A may not induce sufficient cross-protection. The type 19F polysaccharide has the structure of a linear polymer of N-acetylmannosamine-glucose-rhamnose phosphate. Danish type 19A (type 57 in the United States system) polysaccharide contains this repeating unit and, in addition, has side chains of N-acetylglucosamine-galactose phosphate and fucose phosphate. Maternal immunization with type 19F or type 6A polysaccharide during pregnancy elicited high antibody formation in the offspring. Young mice, which received an additional dose of polysaccharide at two weeks of age, showed a higher antibody response than did those that did not receive polysaccharide. These studies reveal that the extensive cross-immunogenicity of pneumococcal group polysaccharides has a basis in chemical structure. Maternal immunization with pneumococcal polysaccharides may enhance the immune response of neonates.

Animals↗
PubMedDate not supplied

Surgical management of the severely multiply handicapped individual.

Thirty-four surgical procedures were performed over a 12-year period on a select population of severely multiply handicapped individuals. Heel cord lengthening, hamstring and adductor releases, as well as selected osteotomies, tenotomies, and arthrodeses (both wrist and foot) were performed. The objectives were improvement in sitting posture, care, and comfort. Independent evaluations of active function, passive function, cosmesis, self-esteem, limb posture, and ease of dressing and hygiene were assessed. Significant improvement was generally noted. No patient was made worse. Selected procedures in the severely multiply handicapped individual have a definite place in patient management.

Adolescent↗