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.

A novel noninstrumented technology (ChemTrak AccuMeter) for the quantitative measurement of analytes in biological fluids was reported at the 1990 Oak Ridge Conference (Clin Chem 1990;36:1591-7). This instrument-free technology has been adapted for the quantitative measurement of high-density lipoprotein (HDL). An in situ lipoprotein separation method has been developed and incorporated into the test for HDL determination. The sensitivity of the assay system has been adjusted so that HDL is measured over a clinically significant range of 250 to 1000 mg/L. This compares to a range of 1000 to 4000 mg/L for the total cholesterol in the earlier reported assay. Like the AccuMeter total cholesterol test, the Accumeter HDL test system is self-contained and consolidates blood separation, lipoprotein separation, and specimen measurement into a single step. The test procedure is simple, and the results are accurate.

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.

high-resolution mass spectrum caled for Ci2H180g m/e 210.12560, found mje 210.126 05.(±)-(4aa,7a,8a/9)-4, 7,8,[3][4][5][6]pyran-3(4H)-one (20). Phenylselenyl chloride (0.086 g, 0.56 mmol) in dichloromethane (1.0 mL) was added dropwise to a solution of keto alcohol 3b in dichloromethane (2.0 mL) cooled to -78 °C under nitrogen. At the completion of addition, the cooling bath was removed and the light orange solution allowed to warm to room temperature. Removal of solvents and chromatography (silica gel, 10:1 hexanes-EtOAc) afforded the crude selenide which was dissolved in toluene (5 mL) and heated to reflux with tri-n-butyltin hydride (0.22 mL, 0.82 mmol) and a catalytic amount of azobis(isobutyrylnitrile). After 60 min, the solution was cooled to room temperature. Concentration and chromatography (silica gel, 10:1 hexanes-EtOAc) provided ether 20 as a colorless oil: Rt 9.38 min (175 °C, isothermal, 6 ft X 1/i in., 5% SE-30 capillary column gas chromatograph); IR (film 2960, 1725, 1150 cm'1; 100-MHz NMR (CDC13) S 0.98 (d, J = 7 Hz, 3 ), 1.14 (s, 3 HO), 1.3-1.8 (m, 6 ), 2.30 (q, J = 7 Hz, 1 ), 3.60 (m, 1 ), 4.1 (m, 4 H); high-resolution mass spectrum caled for C12H1803 mje 210.12560, found mje 210.12685. Acknowledgment. We thank the National Institutes of Health (Grant No. CA23663) for generous financial assistance.Registry No. 3a (isomer 1), 75233-76-0; 3a (isomer 2), 75233-77-1;

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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.

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