Search PubMed⌕ Search

Biomedical subjects

W J Kuhns

Publications and source records attributed to W J Kuhns.

At least 19 recordsLinked to original sources
PubMed1999

A sulfated proteoglycan aggregation factor mediates amyloid-beta peptide fibril formation and neurotoxicity.

Proteoglycans are associated with senile plaques in Alzheimer's disease and may be involved in A beta fibril formation and plaque formation. In vitro, glycosaminoglycans have been shown to inhibit the proteolysis of A beta fibrils, accelerate formation and maintain their stability. To model their interaction, we investigated the binding of a sulfated proteoglycan derived from a natural source; marine sponge Microciona prolifera aggregation factor (MAF). This species-specific re-aggregation of sponge cells has two functional properties, a Ca2+ independent cell binding activity and a Ca2+ dependent self-aggregation. It has been shown that a novel sulfated disaccharide and a pyruvylated trisaccharide are important in the Ca(2+)-dependent MAF aggregation. Aggregation demonstrated by homophilic binding of MAF subunits may be chemically distinct from other heterotypic binding effects. We investigated A beta-MAF interactions and show that MAF induces a structural transition in A beta 40 and A beta 42 from random to beta-structure as detected by circular dichroism spectroscopy. Electron microscopy revealed that the structural transition correlated with an increase in the number of A beta 40 and A beta 42 aggregated that have a truncated fibrillar morphology. Finally, MAF increased A beta-induced toxicity of nerve growth factor (NGF)-differentiated PC-12 cells in the absence of Ca2+. The addition of Ca2+ to MAF-A beta incubations resulted in a moderate attenuation of toxicity possibly due to a reduction in A beta-cell interactions caused by extensive lateral aggregation of the MAF-A beta complexes. Our results indicate that A beta is generally susceptible to proteoglycan-mediated aggregation and fibril formation. We also propose that the MAF model system may be useful in delineating these interactions and represent a means to develop and examine potential inhibitors of the proteoglycan effects.

Alzheimer Disease↗
PubMed1995

Sulfate restriction induces hyposecretion of the adhesion proteoglycan and cell hypomotility associated with increased 35SO4(2-) uptake and expression of a band 3 like protein in the marine sponge, Microciona prolifera.

Sulfate is an important component relating to normal proteoglycan secretion and normal motility in the marine sponge, Microciona prolifera. The following alterations were observed in sponge cells when sulfate free artificial sea water was used as the suspension medium: 1) impairment of aggregation, 2) loss of cell movements, 3) a marked reduction in the secretion of the adhesion proteoglycan (AP). Reversal of this effect occurred if sulfate depleted cells were again rotated in sulfate containing artificial sea water. Motility and reaggregation of sulfate deprived cells could be completely restored by purified AP, but only if cells were first pre-conditioned in normal sea water. Comparisons of 35SO4(2-) uptake between normal and sulfate deprived cells which had been treated to reduce preformed secretions showed a marked increase in 35SO4(2-) uptake and incorporation which could be greatly augmented in the presence of Ca2+/Mg2+. Excessive retention of AP in sulfate starved cells demonstrated by immunostaining suggested that AP secretion and cellular motility may be controlled by a sulfate dependent secretogogue or that undersulfated AP itself had developed a secretory defect. SDS-PAGE of Triton treated cellular extracts demonstrated a 116 kDa 35SO4(2-) sulfated band which co-migrated with AP, but only in extracts derived from sulfate starved cells. Western blots prepared from such extracts incubated in the presence of a monoclonal anti-band 3 antibody demonstrated labelling of a single 97 kDa band only in material from sulfate deprived cells. The absence of this component in normal cell extracts indicated that this protein may be involved in facilitated sulfate transport. This study lends support to a heretofore unrecognized role for sulfate in cell motility and secretion.

Animals↗
PubMed1983

Immunological heterogeneity of carcinoembryonic antigen: immunohistochemical detection of carcinoembryonic antigen determinants in colonic tumors with monoclonal antibodies.

The immunoperoxidase localization of carcinoembryonic antigen (CEA) determinants was studied in colonic adenocarcinomas using four murine monoclonal antibodies to CEA in a bridged avidin:biotin technique. One of the monoclonal antibodies, NP-1, recognizes a CEA epitope shared with the nonspecific cross-reacting antigen and meconium antigen. Two others, NP-2 and NP-3, discriminate two separate CEA epitopes shared with meconium antigen only, whereas NP-4 reacts with a unique determinant expressed on a subpopulation of CEA molecules. The monoclonal antibodies and polyclonal goat antisera against CEA and nonspecific cross-reacting antigen stained columnar epithelial cells in morphologically normal mucosa. Neutrophils were stained by only the NP-1 monoclonal antibody and goat anti-nonspecific cross-reacting antigen antiserum. All moderately differentiated colorectal adenocarcinomas and most of their nodal and liver metastases reacted with the goat antisera and cross-reactive monoclonal antibodies. Thirty % of these primary tumors and most of the nodal and/or liver metastases from six patients with NP-4-positive primary tumors failed to stain with NP-4. These results suggest heterogeneity in the expression of a CEA variant and/or determinant recognized by the NP-4 monoclonal antibody that perhaps identifies a subgroup of colonic cancers which differ in their functional differentiation.

Adenocarcinoma↗
PubMed1981

Carcinoma-related alterations of glycosyltransferases in human tissues.

The glycosyltransferases responsible for catalyzing additions of A, B, and H sugars to cellular acceptors were studied in 23 cases of primary carcinoma. The carcinomas were derived from mouth, tongue, larynx, lung, cervix, esophagus, stomach, and colon. Comparisons of A, B, and H enzymes were made between mucosal extracts from tumor and from normal adjacent tissue and, in the case of gastrointestinal tract, extracts derived from mucosae of individuals free of disease. The most prevalent finding was that of alpha-2-fucosyltransferase (H enzyme) deficiency in tumor extracts from Group A, B, and O patients in relation to the normal tissue counterpart (20 cases). Exceptions were observed in one case of carcinoma of the stomach and in two of seven cases of carcinoma of rectum or sigmoid. In four of nine Group A patients (carcinoma of the mouth, tongue, ascending and transverse colon), N-acetylgalactosaminyltransferases (A enzymes) were demonstrated but were deficient in relation to the normal adjacent counterpart. A enzymes were not demonstrable in normal and tumor extracts from distal colon in five cases. Differences between tumor extracts and normal adjacent tissue were noted in D-galactosyltransferase (B enzyme) derived from carcinomas of larynx and esophagus, but B enzyme was not demonstrated in tumor or normal tissue derived from the sigmoid colon. Study of the normal distribution of H enzyme in gastrointestinal mucosa indicated the presence of relatively high enzyme levels in stomach and upper intestine but low levels in distal colon.

Blood Group Antigens↗
PubMed1980

Empyema of the gallbladder associated with cold agglutinin disease.

A 66-year-old man with jaundice and a high titered cold agglutinin was found to have empyema of the gallbladder, a complication of cystic duct cholelithiasis, confirmed at autopsy. Biliary lithiasis was the apparent result of severe, protracted hemolysis caused by primary cold agglutinin disease.

Aged↗
PubMed1980

Leukemia-induced alterations of serum glycosyltransferase enzymes.

Studies on blood group A and H glycosyltransferase enzymes in 54 patients with acute myeloid leukemia were carried out on serum derived from blood samples taken prior to treatment, and in 16 cases, further tests were performed during clinical remission and at the time of relapse. The enzyme assay procedures, using low-molecular-weight compounds as sugar acceptors and radioactive nucleotide sugars as the donor substrates, have been described by Chester et al. (Eur. J. Biochem., 69:583, 1976). Abnormally low values of H enzyme (expressed as percentage of radioactive sugar incorporated into product; (that is, 1 to 3%) were observed in practically all presentation sera, but the values reverted to normal levels (3 to 15%) at the time of clinical remission and then became low once more with the development of drug resistance and clinical relapse. A enzyme levels measured in presentation sera which had demonstrated abnormal H enzyme were mostly within the normal range. In 2 of 5 A1 patients; sera and in all of three A2 patients increases in enzyme levels were observed in remission as compared with presentation serum samples. The depression of biosynthetic enzymes in acute leukemic sera could not be accounted for on the basis of competitive inhibitors or catabolic enzymes. It is proposed that changes of serum glycosyltransferase enzymes reflect alterations in a leukemic cell population and that knowledge of these changes may be of value in prognosis in acute leukemia.

Blood Proteins↗
PubMed1980

Fluorescent antibody localization of Microciona prolifera aggregation factor and its baseplate component.

Specific rabbit antisera were prepared against purified aggregation factor and its membrane-associated receptor, baseplate, derived from the marine sponge. Microciona prolifera. They were utilized in conjunction with fluorescent-labeled goat anti-rabbit IgG in an assay to demonstrate the surface localizations of both components. The specificity of antibody preparations for AF and BP was demonstrated through inhibition of the rotation-mediated assay by homotypic antibody. This study confirms the presence of aggregation factor on the surface of disaggregated sponge cells maintained in the presence of the divalent cations, Ca++ and Mg++, and its absence when cells are maintained in Ca++ and Mg++-free seawater. The location of BP could also be demonstrated on the cell surface. Aggregation factors and baseplate appear to be heavily distributed on archeocytes and choanocytes, but are localized less intensely on gray cells. Gray cells are typified by yellowish autofluorescence of their intracellular granules in stained and control preparations. The reaction of anti-Microciona aggregation factor with its homotypic factor appeared to be species specificity judged by immunofluorescence assays and by inhibition of rotation-mediated assay by anti-homotypic AF since antibodies prepared against heterotypic AF preparations were unreactive.

Animals↗
PubMed1980

Blood group A-like activity in a long-term renal cell line.

We evaluated two renal carcinoma lines, CAKI-1 and CAKI-2, for the presence of certain cell surface antigens. CAKI-1 was from an individual with blood type O and CAKI-2 from an individual with blood type A. A modification of the standard Chromium-51 release assay was used to determine complement dependent antibody activity in the serum of test subjects against these lines. Seventy per cent of 77 sera contained complement dependent antibody activity against CAKI-2; none was reactive against CAKI-1. Eighty-three and 88 per cent of sera from subjects with blood type B and O were reactive against CAKI-2; only 25 and 26 per cent of the sera from A and AB subjects were reactive against this same line. Both cell lines were agglutinated by anti-H lectin but only CAKI-2 was agglutinated by anti-A lectin. Fourteen of 18 normal control sera and 8 of 9 sera from cancer patients were inhibited by A antigen. A Forssman antigen obtained from guinea pig kidney removed significant complement dependent antibody activity against CAKI-2 when the sera were previously absorbed with this antigen. It would thus seem that CAKI-2 has on its surface an antigen which is either a true blood group A antigen, a Forssman antigen, or a Forssman-like antigen. Of special interest is the long persistence of this antigen in culture, thus permitting further studies characterizing its nature.

ABO Blood-Group System↗