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Biomedical subjects

M Pierce

Publications and source records attributed to M Pierce.

At least 19 recordsLinked to original sources
PubMed1992

Novel glycosylation-defective baby hamster kidney cells.

The plant lectin wheat germ agglutinin (WGA) has previously been used to select more than ten different glycosylation-defective phenotypes in a variety of mammalian somatic cells. Three WGA-resistant phenotypes have now been obtained spontaneously from baby hamster kidney (BHK) cells. These mutant BHK cells exhibit a pattern of cross resistance and sensitivity to multiple plant lectins, suggesting that the cell surface carbohydrates of these cells are altered. Two WGA-resistant BHK phenotypes appear similar to WGA-resistant CHO cells that lack terminal sialic acid and galactose residues on their cell surface carbohydrates. The third WGA-resistant BHK cell phenotype has not previously been seen in WGA-resistant mammalian cells.

Animals↗
PubMed1992

Purification and characterization of rat kidney UDP-N-acetylglucosamine: alpha-6-D-mannoside beta-1,6-N-acetylglucosaminyltransferase.

In order to investigate the molecular mechanism of the specific increase of UDP-N-acetylglucosamine:alpha-6-D-mannoside beta-1,6-N-acetylglucosaminyltransferase (GlcNAcT-V, EC 2.4.1.155) activity after viral or oncogenic transformation, we have purified the enzyme from a Triton X-100 extract of rat kidney acetone powder. GlcNAcT-V was purified by sequential affinity chromatography using first UDP-hexanolamine-agarose and then a synthetic oligosaccharide inhibitor-agarose column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme revealed two major bands at apparent molecular masses of 69 and 75 kDa. The enzyme was recovered in a 26% final yield with a 450,000-fold increase in specific activity to a Vmax of 18.8 mumols/(mg.min). Enzyme activity was stabilized and enhanced by the addition of 20% glycerol, 0.5 mg/ml IgG, and 0.2 M NaCl. The optimal ranges of pH and Triton X-100 concentrations for enzyme activity were 6.5-7.0 and 1.0-1.5%, respectively. The divalent cations, Mn2+, Ca2+, and Mg2+, were each found to have a negligible (less than 10%) effect on activity; moreover, the enzyme was fully active in the presence of 20 mM EDTA. The Km value of the purified enzyme toward a synthetic trisaccharide acceptor was 90 microM, and the Ki value toward a synthetic active site inhibitor was 140 microM.

Animals↗
PubMed1992

Maturation of the hypothalamo-pituitary-gonadal axis of male Syrian hamsters.

Light-microscope immunocytochemistry (ICC) was used to investigate postnatal changes in the morphology of LHRH neurons in the brains of male Syrian hamsters and to relate these changes to more overt maturational developments within the hypothalamo-pituitary-gonadal axis. The animals were maintained under long-day photoperiods (14L:10D), and groups of 6-7 were killed at 10-day intervals from Day 15 to Day 65. Their brains were fixed with 4% paraformaldehyde, sectioned sagittally with a vibratome (75 microns), and processed for ICC using monoclonal LHRH antibody HU4H. Throughout the study period, the hamsters showed a progressive increase in plasma gonadotropin levels, closely followed by an increase in testicular weight and plasma testosterone levels. Histology of the testes revealed that spermatogenesis was already qualitatively completed by Day 35 and quantitative aspects were established by Day 45. Within the brain, LHRH neuronal perikarya were distributed primarily in the medial septal-preoptic area and the diagonal band of Broca; morphologically, these immunopositive neurons were either monopolar or bipolar. The total number of LHRH neurons detected in the areas examined was approximately 440 throughout the developmental period, and the relative proportions of monopolar and bipolar subtypes (86% and 14%, respectively) remained unchanged. In contrast, the area of the perikarya, as determined by autoimage analysis, showed a highly significant age-related increase, both for the monopolar and bipolar neurons. It is suggested that these developmental changes in the LHRH neurons reflect an increase in LHRH synthesis and may, therefore, provide a neuroendocrine trigger for the onset of puberty.

Animals↗
PubMed1992

Undergraduate preparation of the oncology nurse.

Determining appropriate cancer-related content for undergraduate nursing curricula requires careful consideration of content that is needed versus content that is desired for the nurse generalist. Studies have indicated a wide variety of topics and time allotment for this content among schools of nursing. Innovative strategies using games, computers, preceptors, and elective courses have allowed schools of nursing to include more comprehensive coverage of oncology-related topics. Issues concerning clinical oncology nursing opportunities for undergraduate studies still need to be clarified. Undergraduate students must be afforded the legitimacy of their status as novices in nursing and in the specialty of oncology. Didactic and clinical experiences should result in the knowledge and skills needed to develop professionally from novice to expert.

Curriculum↗
PubMed1991

Studies of the developing chick retina using monoclonal antibody 8A2 that recognizes a novel set of gangliosides.

A monoclonal antibody, Mab 8A2, that recognizes a novel set of gangliosides was produced by immunizing a mouse with Embryonic Day 14 chick optic nerve. Immunohistochemical studies of the developing chick retina revealed a complex pattern of Mab 8A2 immunoreactivity. Initially, staining is concentrated in the optic fiber layer in the central retina. Later in development, the most intense staining is seen at the periphery of the retina and 8A2 immunoreactivity appears in other retina layers. In the adult retina, 8A2 immunoreactivity is lost from the optic fiber layer but persists in the inner plexiform layer, inner nuclear layer, and outer plexiform layer. Cell culture experiments showed intense staining of neurites from retinal ganglion cells but no staining of Muller cells. Biochemical characterization of the epitope recognized by Mab 8A2 suggests that it includes a 9-O-acetyl group that is present on five different gangliosides. The 8A2 immunoreactive gangliosides are distinct from and have slower mobilities on thin-layer chromatographs than those recognized by Mab D1.1 which recognizes 9-O-acetyl GD3.

Animals↗
PubMed1991

Immunocytochemical investigation of luteinizing hormone-releasing hormone neurons in Syrian hamsters maintained under long or short days.

Light-microscope immunocytochemistry was used to investigate the LHRH system of adult male Syrian hamsters. Half of the animals were transferred from long to short photoperiods (14L:10D to 6L:18D) for 10 wk, causing plasma gonadotropin levels and the testes to revert to a prepubertal condition. In spite of the marked differences in the reproductive axis between the two groups of hamsters, the number of immunopositive LHRH neurons observed in the preoptic-medial septal area and diagonal band of Broca was approximately 400 in both cases; of these, 87-91% were monopolar and 9-13% were bipolar, regardless of whether the brains were sectioned in a coronal or sagittal plane. These results, therefore, fail to support the hypothesis that photoperiodic changes in the number of LHRH neurons play a major role in controlling the seasonal regression and recrudescence of the reproductive system in the hamster. However, morphometric analysis of the perikarya using an IBAS 2000 automatic image analyzer revealed a photoperiod-related difference. Surprisingly, the perikarya of both monopolar and bipolar LHRH neurons were significantly larger in hamsters that had been maintained on short days, as opposed to long days. These findings, therefore, are in harmony with the view that the inhibitory effect of short days on the reproductive axis is mediated through a suppression of LHRH secretion, which in turn is reflected as an increase in the net content of LHRH within the brain.

Animals↗
PubMed1990

Regulation of N-acetylglucosaminyltransferase V activity. Kinetic comparisons of parental, Rous sarcoma virus-transformed BHK, and L-phytohemagglutinin-resistant BHK cells using synthetic substrates and an inhibitory substrate analog.

Baby hamster kidney (BHK) cells transformed with Rous sarcoma virus, RS-BHK cells, demonstrate a 2.5-fold increase in the activity of N-acetylglucosaminyltransferase V (GlcNAc-T V, EC 2.4.1.155), and this increase in activity appears to be specific for this enzyme. By contrast, a lectin-resistant BHK cell line selected for its ability to grow in high levels of L-phytohemagglutinin, LP3.3, is characterized by a specific decrease in its GlcNAc-T V activity. To test if these alterations in the apparent Vmax of GlcNAc-T V are due to changes in the efficiency of populations of enzymes in RS-BHK and LP3.3 cells compared to the parental BHK cells, we have compared the kinetic properties of the enzymes from these three sources. The Km constants observed for both the sugar nucleotide donor (UDP-GlcNAc) and two synthetic trisaccharide acceptors were indistinguishable. The Vmax values toward three synthetic acceptors were also determined first for the BHK GlcNAc-T V, and they varied by over 5-fold. When these values were measured for the variant and transformed cell enzymes, however, similar 5-fold differences were still observed, although the absolute values for these acceptors were all higher or lower for the RS-BHK and LP3.3 enzymes, respectively. In addition, we have synthesized a deoxygenated analog of the specific GlcNAc-T V acceptor, beta GlcNAc(1,2) alpha Man(1,6) beta ManOR, where the reactive 6'-OH group has been removed, and the resulting trisaccharide was found to be a competitive inhibitor of the enzyme. The Ki for this inhibitor was near 70 microM for the GlcNAc-T V from all three sources. These kinetic comparisons demonstrate that the enzymes from the three cell types have kinetically indistinguishable active sites. These results suggest that the differences in the apparent Vmax values among the cell types are most likely due to alterations in the number of active molecules rather than in the modulation of either their catalytic activities or specificities.

Animals↗
PubMed1990

An enzyme-linked immunosorbent assay for N-acetylglucosaminyltransferase-V.

The development of an enzyme-linked immunosorbent assay (ELISA) for uridine 5'-diphospho-N-acetyl-glucosamine: alpha mannoside beta 1----6 N-acetylglucosaminyltransferase (GnT-V) is reported. The assay quantitates the enzymatic conversion of the specific synthetic GnT-V acceptor GlcNAc beta 1----2Man alpha 1----6Man beta-R (5) to the product GlcNAc beta 1----2[GlcNAc-beta 1----6]Man alpha 1----6Man beta-R (6) when these oligosaccharide structures were covalently attached to bovine serum albumin which was then coated on microtiter wells. Conversion of 5 to 6 was detected using a polyclonal antiserum raised against the product 6 and from which antibodies cross-reacting with acceptor 5 had been removed by affinity adsorption. GnT-V activity detected by ELISA was linearly proportional to both enzyme concentration and time under appropriate experimental conditions where 50-300 fmol of product was formed per microtiter well. GnT-V activity could be measured by ELISA in Triton X-100 extracts of hamster kidney acetone powder and in human serum. The twofold increase in GnT-V activity which is known to accompany Rous sarcoma virus transformation of baby hamster kidney cells could also be quantitated using the ELISA.

Animals↗
PubMed1990

Co-transformation of Lec 1 CHO cells with N-acetylglucosaminyltransferase 1 activity and a selectable marker.

In animal cells, the enzyme alpha(1,3)-mannoside-beta(1,2)-N-acetylglucosaminyltransferase I (GlcNAc-TI, EC.2.4.1.101) catalyzes the addition of N-acetylglucosamine to the ASN-linked Man GlcNAc oligosaccharide. The Chinese hamster ovary (CHO) mutant cell line Lec1 is deficient in this enzyme activity and, therefore, accumulates mannose-terminating cell surface ASN-linked oligosaccharides. Consequently, Lec1 cells are sensitive to the cytotoxic effects of the mannose-binding lectin Concanavalin A (Con A). Lec1 cells were co-transformed with human DNA from A431 cells and eukaryotic expression plasmids containing the bacterial neo gene by calcium phosphate/DNA-mediated transformation. Co-transformants were selected for resistance to Con A and G-418. DNA from a primary co-transformant was purified and used to transform Lec1 cells, resulting in secondary co-transformants. Both primary and secondary co-transformants exhibited in vitro GlcNAc-TI-specific enzyme activity. DNA gel blot analysis indicated that secondary co-transformants contained both human and neo sequences.

Animals↗
PubMed1989

Prospective randomised controlled trial of methods of call and recall for cervical cytology screening.

OBJECTIVE: To discover whether systematic methods of call and recall are more effective than a non-systematic method and to see which of the two systematic methods was more effective. DESIGN: Prospective randomised controlled trial over a year. SETTING: One group general practice. PATIENTS: 416 Women over 35 eligible for a smear test who had never had a cervical smear test or in whom a smear test was overdue (previous test more than five years before). INTERVENTIONS: One group received written invitations to have a smear taken. The second group had their notes tagged so that the doctor would remind them (when they attended for another reason) to have a smear test. No special intervention was made in the third group. MAIN OUTCOME MEASURE: Performance of a cervical smear test during the year of the study. RESULTS: 32% (45/140) of the screened group, 27% (39/142) of the tagged group, and 15% (20/134) of the control group had a smear test during the year. The percentage of women having a smear test in the screened group was not significantly different from that in the tagged group, but the percentages in the two groups were significantly different from that in the control group. Whether a woman had had a previous smear test significantly affected the uptake of the invitation to have a smear test independently of the method of invitation. CONCLUSIONS: The systematic methods of call and recall were more effective than a non-systematic method. There was no significant difference between the two systematic methods (sending letters or tagging the notes) at one year.

Adult↗
PubMed1989

DNA-mediated transformation of N-acetylglucosaminyltransferase I activity into an enzyme deficient cell line.

N-acetylglucosaminyltransferase I (GlcNAc-TI) catalyzes the first reaction in the conversion of ASN-linked cell surface oligosaccharides from a mannose-terminating structure to more complex carbohydrate structures. The mutant Chinese hamster ovary (CHO) cell line, Lec1, is deficient in this enzyme and, therefore, shows increased sensitivity to the lectin, Concanavalin A, which binds to the mannose-terminating oligosaccharides that accumulate on Lec1 cell surface glycoproteins. Spontaneous revertants of the Lec1 phenotype have never been observed. We report here the isolation of stable revertants of Lec1 cells to the parental CHO cell lectin-resistance phenotype after DNA-mediated transformation with human DNA. Both primary and secondary transformants express varying levels of GlcNAc-TI enzyme activity which was stable even when the cells were cultured in nonselective conditions. Human alu repeat DNA sequences are present in the primary transformants, but these sequences could not be detected in the secondary transformants.

Animals↗
PubMed1988

Recognition of oligosaccharide substrates by N-acetyl-glucosaminyltransferase-V.

Six analogs of the trisaccharide 8-methoxycarbonyloctyl 6-O-[2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-alpha-D-mannopyrano syl] -beta-D-mannopyranoside (3), a previously reported acceptor for N-acetylglucosaminyltransferase-V (GnT-V) have been chemically synthesized and evaluated as GnT-V acceptors. Replacement of the beta-D-man rho-O(CH2)8COOMe "reducing end" of 3 by beta-D-Glc rho-O(CH2)7 CH3 gave octyl 6-O-[2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl]-alpha-D- mannopyranosyl)-beta-D-glucopyranoside (5) whose activity was indistinguishable from that of 3. Removal of the 4-OH group of the beta-D-Glc residue in 5 had little effect on the activity, while the corresponding 4-O-methyl derivative was twice as active. Replacement of the C-6 pro-R hydrogen of the same residue by a methyl group gave the L-glycero-D-gluco derivative 8, whereas replacement of the corresponding pro-S hydrogen gave the D-glycero-D-gluco compound 9. Trisaccharide 8, whose rotameric distribution about the C-5-C-6 bond is sterically biased towards the gg conformation was less than half as active as 5 as a GnT-V acceptor, whereas 9, which is biased towards the gt conformation, was more than twice as active. These results provide evidence for the conformational control of oligosaccharide biosynthesis.

Alcohols↗
PubMed1988

The trisaccharide beta-D-GlcpNAc-(1----2)-alpha-D-Manp-(1----6)-beta-D-Manp, as its 8-methoxycarbonyloctyl glycoside, is an acceptor selective for N-acetylglucosaminyltransferase V.

Incubation of the trisaccharide acceptor, beta-D-GlcpNAc-(1----2)-alpha-D-Manp-(1----6)-beta-D-Manp-O( CH2)8CO2Me with sonicates of Rous sarcoma-transformed baby-hamster kidney cells, which contain N-acetylglucosaminyltransferase V activity, resulted in the production of beta-D-GlcpNAc-(1----2)-[beta-D-GlcpNAc-(1----6)]-alpha-D-Manp-(1- ---6)- beta-D-Manp-O(CH2)8CO2Me (4). The product of the enzymic reaction was identified by comparison of its 1H-n.m.r. spectrum with that of authentic 4 whose chemical synthesis is also described.

Animals↗
PubMed1988

Comparison of N-acetylglucosaminyltransferase V activities in Rous sarcoma-transformed baby hamster kidney (RS-BHK) and BHK cells.

Recent studies have demonstrated that Rous sarcoma virus-transformed baby hamster kidney (RS-BHK) cells express twofold higher levels of those N-linked oligosaccharides that contain the sequence [GlcNAc-beta(1,6)Man (1,6)] compared to nontransformed parental BHK cells (Pierce and Arango, J. Biol.Chem. 261, 10772 [1986]). We have investigated in RS-BHK and BHK cells the activity of UDP-GlcNAc:alpha-D-mannoside beta(1,6)N-acetylglucosaminyltransferase V, the enzyme that begins the synthesis of the sequence that is increased in the RS-BHK cells. We have measured GnT V activity using UDP-[3H]-GlcNAc and a synthetic oligosaccharide acceptor, GlcNAc beta(1,2)Man alpha(1,6)Man beta-O-(Ch2)8COOCH3, separating the radioactive product by a newly devised reverse-phase chromatographic technique. Assayed under optimal conditions, the specific activity of GnT V is about fourfold higher in RS-BHK sonicates than in BHK sonicates, suggesting that this increase in activity may be the primary mechanism that causes the increase in [GlcNAc beta(1,6)Man] sequences in the RS-BHK cells. The apparent Km values of the enzymes in RS-BHK and BHK cell sonicates for UDP-GlcNAc and the synthetic acceptor are similar, as are the pH optima. These results suggest that the increase in GnT V-specific activity in RS-BHK cells is not caused by the presence in these cells of a GnT V with markedly different kinetic properties.

Acetylglucosamine↗
PubMed1987

Activity of UDP-GlcNAc:alpha-mannoside beta(1,6)N-acetylglucosaminyltransferase (GnT V) in cultured cells using a synthetic trisaccharide acceptor.

N-acetylglucosaminyltransferase V activity has been measured under saturating conditions in the extracts of seven cultured cell lines using as substrates, UDP-[3H]-GlcNAc and a synthetic 8-methoxylcarbonyloctyl trisaccharide. The unreacted sugar-nucleotide and its breakdown products were separated from the radiolabeled tetrasaccharide product by reverse-phase chromatography. Enzyme activity was present in six of the cell lines, which were derived originally from either human, mouse, or hamster tissues, with the highest activity in mouse lymphoma BW5147 cells. The PHAR 2.1 variant cell line, derived from the BW5147 line, expressed no detectable activity.

Animals↗
PubMed1987

Clinically unsuspected cardiac disease in patients with cerebral ischaemia.

In a 6 month prospective study of 232 patients with cerebral ischaemia, 100 (43%) had a prior history of heart disease. In 22 of the patients with prior heart disease an unsuspected cardiac disorder was subsequently detected (6 atrial fibrillation, 13 cardiomegaly or left ventricular hypertrophy and 3 ischaemic heart disease). In patients without prior heart disease, 47 (20%) were found to have cardiac disease: 6 atrial fibrillation, 31 cardiomegaly or left ventricular hypertrophy 9 ischaemic heart disease and 1 left bundle branch block. Previously unsuspected or asymptomatic cardiac disease is common in patients with cerebral ischaemia.

Adult↗
PubMed1986

Rous sarcoma virus-transformed baby hamster kidney cells express higher levels of asparagine-linked tri- and tetraantennary glycopeptides containing [GlcNAc-beta (1,6)Man-alpha (1,6)Man] and poly-N-acetyllactosamine sequences than baby hamster kidney cells.

The alterations in complex-type N-linked oligosaccharides that can occur when an animal cell line is transformed by two dissimilar viruses were examined by comparing the N-linked oligosaccharides of baby hamster kidney (BHK) cells, metabolically radiolabeled with [2-3H]mannose, to the same class of oligosaccharides from BHK cells separately transformed by Rous sarcoma virus (RS-BHK), an RNA retrovirus, and polyoma virus (PY-BHK), a DNA papovavirus. Based on experiments that utilized serial lectin affinity chromatography, glycosidase digestions, and methylation analyses, both RS-BHK and PY-BHK cells demonstrated a significant increase in the relative amounts of tri- and tetraantennary complex-type N-linked oligosaccharides containing the branching sequence, [GlcNAc-beta(1,6)Man-alpha(1,6)Man], compared to the nontransformed BHK cells. In addition, almost all of the poly-N-acetyllactosamine sequence, [GlcNAc-beta(1,3)-Gal-beta(1,4)], was expressed on the tri- and tetraantennary N-linked oligosaccharides from BHK and RS-BHK cells that contain the sequence, [GlcNAc-beta(1,6)Man-beta(1,6)Man]. The increase in the relative amounts of this latter sequence in the transformed cells, therefore, most likely results in an increase in the amount of poly-N-acetyllactosamine sequence on the N-linked glycopeptides of these cells. The analysis of the degree of sialylation of the complex-type N-linked oligosaccharides from BHK and RS-BHK cells by ion exchange chromatography revealed no apparent differences, and in both of these cell types approximately 3% of the glycopeptide fraction radiolabeled with mannose was recovered in a highly negatively charged fraction that was identified by keratanase digestion to be keratan sulfate.

Acetylglucosamine↗