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Biomedical subjects

E Holmes

Publications and source records attributed to E Holmes.

At least 91 records · Page 5Linked to original sources
PubMed1986

Novel blood group H glycolipid antigens exclusively expressed in blood group A and AB erythrocytes (type 3 chain H). II. Differential conversion of different H substrates by A1 and A2 enzymes, and type 3 chain H expression in relation to secretor status.

The novel A-associated H antigen (type 3 chain H), described in the accompanying paper (Clausen, H., Levery, S.B., Kannagi, R., and Hakomori, S. (1986) J. Biol. Chem. 261, 1380-1387), as well as globo-H were found to be present in greater quantity in A2 erythrocytes than in A1 erythrocytes. A1 erythrocytes contain the repetitive A epitope (type 3 chain A) (Clausen, H., Levery, S.B., Nudelman, E., Tsuchiya, S., and Hakomori, S. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 1199-1203), which is defined by A1-specific monoclonal antibody TH-1, in addition to globo-A. The ability of alpha-GalNAc transferase from A1 and A2 serum to catalyze the conversion of type 2 chain H, type 3 chain H, and globo-H to type 2 chain A, type 3 chain A, and globo-A, respectively, was compared. The conversion to type 3 chain A and globo-A occurred to a minimal degree in the presence of the A2 enzyme as compared with the A1 enzyme, particularly at low substrate concentration. Although a lower conversion from type 2 chain H to type 2 chain A was also observed in the presence of the A2 enzyme than in the presence of the A1 enzyme, the conversion of type 2 chain H to type 2 chain A was less restricted than the type 3 chain conversion catalyzed by the A2 enzyme, particularly at low substrate concentration. The conversion from globo-H to globo-A was essentially absent in the presence of the A2 enzyme. Since the expression of type 1 chain H in erythrocytes is dependent on secretor status, the distribution of type 3 chain H and globo-H in erythrocytes from secretors and non-secretors was compared. These antigens appeared to be present in the same quantity in erythrocytes of secretors and nonsecretors.

ABO Blood-Group System↗
PubMed1986

The hormonal regulation of gene expression of glial markers: glutamine synthetase and glycerol phosphate dehydrogenase in primary cultures of rat brain and in C6 cell line.

Increases in the mRNA levels of two neuroglial markers, glutamine synthetase (EC 6.3.1.2; GS) and glycerolphosphate dehydrogenase (EC 1.1.1.8; GPDH), were observed in hydrocortisone-treated cultures of astrocytes and oligodendrocytes, respectively, and in C6 cells by Northern blot analysis and in situ hybridization. In vitro transcription assays demonstrated increased GS transcription in isolated nuclei from hydrocortisone (HC)-treated primary cultures of astrocytes and C6 cells, relative to untreated cells. This increased transcription is reflected in increased GS mRNA levels in the cytoplasm and increased levels of GS protein synthesis. Sodium butyrate (NaB) blocked the glucocorticoid-mediated increase in GS transcription in the primary cultures of astrocytes but not in C6 cells. From our earlier observations (Kumar et al: J Neurochem 43:1455-1463, 1984) we found NaB in combination with HC to increase the levels of GS mRNA and GS protein synthesis (Weingarten et al: FEBS Lett 126:289-291, 1981). We now report that NaB, alone or in combination with HC, does not increase the rate of transcription, suggesting that NaB plays a role in post-transcriptional regulation of GS in C6. In addition, we report the presence of two distinct sizes of GS mRNA, 2.9 and 1.8 kb, in the primary cultures of astrocytes and C6 cells.

Animals↗
PubMed1986

Serum factors which suppress natural cytotoxicity in cancer patients.

Spontaneous cytotoxicity mediated by natural killer (NK) cells is potentially an important mechanism of immunosurveillance against tumor or virus-infected cells. NK activity is impaired in many cancer patients. This study investigated the possibility that humoral factors are responsible for depressed NK activity in cancer patients and examined whether these factors were anti-lymphocyte antibodies (ALA) or immune complexes. The degree of NK suppression induced by 20 cancer patients' sera was determined by preincubating normal peripheral blood mononuclear cells with cancer sera. Eight of the 20 serum samples from cancer patients had NK-suppressive humoral factors. Elimination of immune aggregates by ultracentrifugation did not remove the inhibitory factors. The degree of NK suppression induced by cancer sera correlated with the extent of NK impairment in the serum donors (p less than 0.05). The cancer sera was examined for the presence of ALAs using flow cytometry. All cancer sera tested contained only low ALA reactivity to NK cell-enriched suspensions (less than 15%). This is in marked contrast to previous reports regarding NK-inhibitory systemic lupus erythematosus sera which contained large amounts of large granular lymphocyte (LGL) reactive ALAs. This study demonstrates that certain cancer sera suppress NK cell function. These inhibitory serum factors do not appear to be LGL-reactive ALAs or immune aggregates.

Adult↗
PubMed1983

Selective fetal malnutrition: the effect of in vivo ethanol exposure upon in vitro placental uptake of amino acids in the non-human primate.

In vitro uptake (45 and 90 minutes) of amino acids, alpha-amino isobutyric (AIB) and valine (VAL), was measured in six placentae from the nonhuman primate, Macacca fascicularis. Three of the pregnant primates were chronically treated with ethanol before and throughout pregnancy (CHR); one during the last trimester only (LT); and two were controls (C). Compared to the C placentae, the LT placenta had significantly decreased uptake only for AIB at 45 min: 33.4 +/- 6.8% reduction (mean +/- S.E.) (P less than 0.05). In contrast, the CHR placentae demonstrated significantly reduced uptake (P less than 0.01) for both amino acids at both time points. Percent reduction at 45 and 90 min: AIB, 35.2 +/- 6.5% and 32.6 +/- 5.6% and VAL, 38.7 +/- 2.9% and 22.1 +/- 4.1%. The results indicate that chronic in vivo ethanol exposure impairs the in vitro placental uptake of two actively transported amino acids, using an animal with a placenta almost identical to the human.

Aminoisobutyric Acids↗
PubMed1982

Immunological characterization of Escherichia coli B glycogen synthase and branching enzyme and comparison with enzymes from other bacteria.

Escherichia coli B glycogen synthase and branching enzyme, although similar in amino acid composition, had no significant immunological cross-reactivity. The N-terminal sequences of the glycogen synthase were rich in hydrophobic residues, whereas branching enzyme had a higher content of acidic and basic residues. However, residues 21 to 28 of glycogen synthase and 7 to 14 of branching enzyme shared six of eight residues in common. Two fractions of branching enzyme, branching enzymes I and II, which can be isolated from E. coli B cell extracts, have been shown to be immunologically identical, suggesting that only one type of branching enzyme activity is present in E. coli B. Evidence has been obtained which indicates that E. coli B glycogen synthase and branching enzyme are antigenically very similar to glycogen synthases and branching enzymes from other enteric bacteria. No cross-reactivity with either enzyme was observed in cell extracts from photosynthetic bacteria.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1978

Comparison of chemical composition of peritoneal fluid and serum: a method for monitoring dialysis patients and a tool for assessing binding to serum proteins in vivo.

It is hypothesized that peritoneal fluid might be used as an alternative vehicle for monitoring the clinical chemistry of patients on peritoneal dialyses and save these patients the venesection and resultant blood loss. Peritoneal fluid was obtained before 47.2% of 106 dialysis treatments and compared with simultaneous serum samples. Very close correlation was noted for phosphorus, uric acid, blood urea nitrogen, creatinine, potassium, bicarbonate, and sodium (r greater than 0.82, p less than 10(-6)), and we conclude that peritoneal fluid may be useful for monitoring these chemistries. The peritoneal fluid concentrations of calcium and albumin were consistently 20% and 43% lower than the corresponding serum values. Because the peritoneal fluid is in equilibrium with the serum, it could also be used to measure protein binding of low molecular-weight substances in vivo that cross the peritoneal membrane. The results presented here fail to support the suggestion that urate is bound to serum proteins in vivo.

Aged↗