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W H Schrier

Publications and source records attributed to W H Schrier.

8 recordsLinked to original sources
PubMed1998

Development of FlexSure HP--an immunochromatographic method to detect antibodies against Helicobacter pylori.

We describe a solid-phase immunochromatographic serologic test, FlexSure HP, to detect IgG antibodies against Helicobacter pylori. H. pylori colonize the stomach and proximal duodenum, cause ulcer disease and mucosa-associated lymphoid tissue lymphoma, and have a role in the development of other disorders, including gastric adenocarcinoma. FlexSure HP consists of a test strip, conjugate pad, and absorbent pad, in a novel reverse-flow chromatography format. In these studies, FlexSure HP was demonstrated to be specific for IgG antibodies against H. pylori. The reactive cutoff of the test was consistent with [13C]urea breath test and commercially available ELISAs. FlexSure HP had 94% sensitivity, 88% specificity, and 91% accuracy relative to [13C]urea breath test; and 95% sensitivity, 94% specificity, and 95% overall agreement relative to high-molecular-mass cell-associated protein enzyme immunoassay (HM-CAP EIA). FlexSure HP is a simple-to-perform, visually read test requiring no specialized training, equipment, or instrumentation, and yields rapid, accurate, qualitative results.

Adult↗
PubMed1996

Comparison of rapid serological tests (FlexSure HP and QuickVue) with conventional ELISA for detection of Helicobacter pylori infection.

BACKGROUND: There is a need for accurate and rapid tests for Helicobacter pylori infection especially since the recent National Institutes of Health Consensus Development Conference on H. pylori in peptic ulcer disease charged the medical community with treating H. pylori infection in all patients with H. pylori and ulcer disease. METHODS: We prospectively compared a simple, rapid serological test (FlexSure HP, SmithKline Diagnostics) for the detection of serum IgG antibodies against H. pylori with another rapid test (QuickVue, Quidel) and two enzyme immunoassays (HM-CAP, Enteric Products, and PyloriStat, BioWhittaker). Serum samples from 551 individuals including both symptomatic patients (196) and asymptomatic volunteers (355) were tested for the presence of IgG antibodies against H. pylori. The presence or absence of active H. pylori infections was determined using the [13C]-urea breath test. RESULTS: All of the serological tests performed well. FlexSure HP had calculated sensitivity, specificity, and accuracy of 94.4, 87.6, and 91.1%, respectively, relative to the urea breath test. In 49 of the 551 samples, the urea breath test and FlexSure HP did not agree. Those samples were tested with HM-CAP immunoassay to confirm presence or absence of IgG antibodies against H. pylori. After the resolution of the discordant results, the sensitivity, specificity, and accuracy of FlexSure HP were 96.0, 95.1, and 95.6%, respectively, and were comparable to HM-CAP and PyloriStat. FlexSure HP was compared with histology or culture in 75 cases, and the accuracy was 100%. FlexSure HP and QuickVue were compared using 200 serum samples. FlexSure HP was more specific (88.7 vs 79.4%) and accurate (91 vs 84%) than QuickVue (p < 0.05 for both), relative to the urea breath test with discordant samples unresolved. FlexSure HP was also simpler to use, easier to interpret, and faster than QuickVue. FlexSure HP required no sample dilution, one reagent, four steps, and 5 min to complete. CONCLUSION: FlexSure HP is an excellent option for in-office tests for the physician who desires immediate results or for small laboratories that do not have the volume of H. pylori testing to justify ELISA test formats.

Adolescent↗
PubMed1985

Isofocusing of antigenic small nuclear ribonucleoproteins. II. Preparative isolation.

In a companion report (T.B. Okarma, W.S. Schrier, and R. Feinbaum, 1985, Anal. Biochem. 147, 27-37) the behavior of small nuclear ribonucleoproteins (snRNPs) in native isofocusing gels was characterized. This communication extends those findings and describes a gentle procedure for the preparative isolation of snRNPs in native form from cultured murine L-5178y leukemia cells using sucrose density gradient centrifugation, preparative isofocusing, and gel filtration chromatography. Isofocusing in granulated gels separated intact uridylic acid (U)-snRNPs from tRNA and La RNPs. The U-snRNPs remained immunoprecipitable by lupus antisera throughout fractionation. The final product obtained in 2% yield contained primarily U1 and U2 snRNAs and lesser amounts of U3, U4, U5, and U6, along with the core U-snRNP polypeptides A-G. The core polypeptides displayed apparent pI's which ranged from 4.5 to 9.5 when analyzed by two-dimensional gel electrophoresis. Proteins B (28,000), D (16,000), and E (13,000) exhibited isoelectric variants. The Sm determinant proteins B' (28,000) and E (13,000) isofocused as basic peptides with apparent pI's of 9.5 and 8.5, respectively. The purity of the final fractions compared well with that of immunoprecipitates and the procedure reproducibly generated yields of native snRNPs sufficient for in vitro studies of their biological function.

Animals↗
PubMed1983

Isolation from Friend erythroleukemia cells of an RNase-sensitive nuclear matrix fibril fraction containing hnRNA and snRNA.

Chromatin-depleted nuclei (CDN) were prepared from Friend erythroleukemia cell nuclei by partial digestion with DNase I and extraction of the chromatin by 2 mM EDTA as described in the preceding paper (Long and Ochs, 1983. Biol. Cell 48, 99-108). These structures contained dense networks of matrix fibrils surrounded by distinct laminae but no morphologically distinct residual nucleoli. CDN disrupted by gentle shearing or 1 microgram/ml RNase were fractionated into laminae and matrix fibrils by differential centrifugation. Protein composition of the lamina fraction was dominated by two prominent lamina proteins that were not detectable in the matrix fraction. Mild RNase treatment led to a conversion of the fibrous network to a particulate morphology while mild shearing resulted in an apparently unaltered fibril fraction. The matrix fibril fractions contained hnRNP proteins and the snRNAs. These results suggest that EDTA-prepared CDN may provide a system for studying snRNP-hnRNP interactions and hnRNP processing that is less complex than intact nuclei.

Animals↗
PubMed1983

Immunoelectron microscopic localization of snRNPs.

Small nuclear ribonucleoprotein particles (snRNPs) were identified in nuclear sonicates of Novikoff hepatoma ascites cells and in intact Novikoff hepatoma and PtK2 cells by immunofluorescence and immunoelectron microscopy. Auto-antibodies (anti-Sm and anti-RNP) obtained from patients with systemic lupus erythematosus an autoimmune disease, were used to localize snRNP particles. The Sm antibody is specific for U1, U2, U4, U5 and U6 containing snRNPs. The RNP antibody is specific for only U1 containing snRNPs. Isolated particles, 120 +/- 10 A in diameter, were found to be associated with ferritin-conjugated goat anti-human antibodies coupled to Sm antibodies. In addition, these particles (snRNPs) were occasionally associated with larger particles measuring 230 +/- 10 A in diameter which are presumed to be hnRNP particles. Double label immunofluorescence and immunoelectron microscopy have shown Sm and RNP antibodies to colocalize in PtK2 cells. However, the perinucleolar chromatin and juxtanuclear envelope chromatin was devoid of RNP immunostaining. Therefore, U1 containing snRNPs do not appear to be in these regions. The Sm antibody localizes in a nuclear network including the perinucleolar chromatin and juxtanuclear envelope chromatin. Cells treated with the drug DRB (5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole), which inhibits hnRNA synthesis, show an altered pattern of Sm immunostaining. Such cells contain large clusters of snRNPs which do not extend to the perinucleolar chromatin or perinuclear lamina chromatin. Nuclear matrix preparations maintain an snRNP nuclear network as visualized by Sm immunofluorescence. It is notable that the size and density of the immunostained particles in the nuclear network during interphase, is similar to that of interchromatinic granules.

Animals↗
PubMed1979

The enzymatic hydrolysis of the phosphate ester bond in some thionucleotides.

We prepared the 5'- and 3'-O-phosphorothioate esters of the antitumor agent O2 : 2'-anhydro-1-beta-D-arabinosylcytosine. We also included in this study esters of 2'-thio-2'-deoxycytidine, namely, 2'-S-dCyd-2' : 3'-P, 2'-S-dCyd-2'-P, and 2'-S-dCyd-3'-P, along with natural nucleotides. These compounds were subjected to the action of Escherichia coli alkaline phosphatase, potato acid phosphatase, and bovine pancreatic ribonuclease A. The data were analyzed by Lineweaver-Burk plots to obtain Km and KI values. Only 2'-S-dCyd-2'-P was a substrate for alkaline phosphatase; the anhydro-araCyt phosphorothioates were good competitive inhibitors, while 2'-S-dCyd-3'-P did not associate with the enzyme. Acid phosphatase hydrolyzed all four monoesters investigated, including the S-phosphorothioate. The cyclic phosphorothioate, 2'-S-dCyd-2' : 3'-P was neither hydrolyzed by, nor associated with, ribonuclease A. ORD spectroscopy was also used in an attempt to relate the structural features of analogs to the peculiarity of their hydrolysis.

Acid Phosphatase↗