Biomedical subjects
J Crabb
Publications and source records attributed to J Crabb.
The EGF-inducible protein EIP-1 of migrating normal and malignant rat liver epithelial cells is identical to plasminogen activator inhibitor 1 and is a component of the ECM migration tracks.
Induction of rat liver epithelial cell migration by epidermal growth factor (EGF) changes the expression pattern of secreted proteins. The expression of the early induced glycoprotein EGF-inducible protein No. 1 (EIP-1) correlates with the migratory behavior of both normal and Ha-ras-transformed, tumorigenic cells and is deposited into the ECM migration tracks. The sequence of two clones from a cDNA library of EGF-induced cells and the amino terminal sequence of the purified protein revealed that EIP-1 is identical to rat plasminogen activator inhibitor 1 (PAI-1). Based on the migration-linked expression pattern of EIP-1/PAI-1 it is proposed that the inhibitor is required for the migration of these cells, but not sufficient to stimulate it.
A photoreceptor calcium binding protein is recognized by autoantibodies obtained from patients with cancer-associated retinopathy.
Cancer-associated retinopathy (CAR), a paraneoplastic syndrome, is characterized by the degeneration of retinal photoreceptors under conditions where the tumor and its metastases have not invaded the eye. The retinopathy often is apparent before the diagnosis of cancer and may be associated with autoantibodies that react with specific sites in the retina. We have examined the sera from patients with CAR to further characterize the retinal antigen. Western blot analysis of human retinal proteins reveals a prominent band at 26 kD that is labeled by the CAR antisera. Antibodies to the 26-kD protein were affinity-purified from complex CAR antisera and used for EM-immunocytochemical localization of the protein to the nuclei, inner and outer segments of both rod and cone cells. Other antibodies obtained from the CAR sera did not label photoreceptors. Using the affinity-purified antibodies for detection, the 26-kD protein, designated p26, was purified to homogeneity from the outer segments of bovine rod photoreceptor cells by Phenyl-Sepharose and ion exchange chromatography. Partial amino acid sequence of p26 was determined by gas phase Edman degradation and revealed extensive homology with a cone-specific protein, visinin. Based upon structural relatedness, both the p26 rod protein and visinin are members of the calmodulin family and contain calcium binding domains of the E-F hand structure.
Purification and primary structure of glucagon from ostrich pancreas splenic lobes.
Glucagon is a highly conserved polypeptide hormone which appears to play a more important role in regulation of glycaemia in birds than insulin. Ostrich glucagon was isolated and purified from ostrich pancreas splenic lobes using an adapted acid ethanol extraction procedure, gel filtration, ion exchanges, and HPLC steps. The purified glucagon fraction appeared to contain small quantities of a more acidic contaminant (polyacrylamide gel isoelectric focussing, PAGE) but appeared homogeneous on SDS-PAGE. Amino acid analysis and sequence analysis showed identity with the duck hormone. Identity with the duck hormone was confirmed by liquid phase as well as gas phase sequencing. The ostrich glucagon preparation seemed to have a higher Km than the porcine homologue in stimulating glycerol release from isolated chicken adipocytes.
Protective efficacy of immunization with capsular antigen against experimental infection with Bacteroides fragilis.
The protective efficacy afforded by immunization with the capsular antigen of Bacteroides fragilis against abscess formation and bacteremia due to this organism was studied in an experimental rat model of intraabdominal sepsis. Of unimmunized animals, animals immunized with methylated bovine serum albumin and complete Freund's adjuvant, and animals immunized with lipopolysaccharide of Bacteroides thetaiotaomicron, greater than 90% developed abscesses when challenged intraperitoneally with strains of B. fragilis or Bacteroides distasonis (given with an enterococcus) or with the cecal contents of meat-fed rats. In contrast, animals immunized with B. fragilis capsular polysaccharide, given with or without methylated bovine serum albumin and complete Freund's adjuvant, and animals immunized with the outer membrane of B. fragilis strain 23745 were protected to a significant degree from abscesses caused by challenge with B. fragilis or B. distasonis. Such immunization had no overall effect on the development of abscesses in animals challenged with the entire cecal contents of meat-fed rats; however, B. fragilis was eliminated from the abscesses of these animals. Animals immunized with the capsular polysaccharide were protected from early B. fragilis bacteremia.