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S B Huang

Publications and source records attributed to S B Huang.

9 recordsLinked to original sources
PubMed1997

A specificity comparison of four antisense types: morpholino, 2'-O-methyl RNA, DNA, and phosphorothioate DNA.

Cell-free translation studies were carried out to compare the efficacy and specificity of four antisense structural types: DNA, phosphorothioate DNA (S-DNA), 2'-O-methyl RNA, and Morpholino oligos, a novel antisense structural type. In these studies, translational inhibition was assessed for two 20-mers of each structural type, where one 20-mer was complementary to its target sequence in rabbit alpha-globin mRNA and the other 20-mer contained three mispairs to that same target sequence. It is shown that at low concentration of antisense oligomer (50 nM) all four types provide high specificity, but the Morpholino oligos and 2'-O-methyl RNA afford better efficacy. At high oligomer concentration (3.5 microM), all four types provide high efficacy, but the Morpholino oligos and 2'-O-methyl RNA provide substantially better specificity than the DNA and S-DNA.

Animals↗
PubMed1997

Morpholino and phosphorothioate antisense oligomers compared in cell-free and in-cell systems.

Morpholino and phosphorothioate (S-DNA) antisense oligos were compared in both cell-free and in-cell translation systems. In the most stringent test of specificity in the cell-free system, a globin-targeted S-DNA oligo was found to inhibit its target sequence at concentrations of 10 nM and above, but the sequence-specific component of this inhibition dropped below 50% at concentrations of 100 nM and above. A corresponding Morpholino oligo achieved even higher inhibition at 10 nM, but in contrast to the S-DNA, with the Morpholino, the sequence-specific component of this inhibition remained above 93% at a concentration of 3000 nM. In this same cell-free test system, several S-DNA oligos exhibited substantial undesired nonantisense effects at concentrations of 300 nM and above, whereas corresponding Morpholino oligos exhibited little or no nonantisense activity through a concentration of 3000 nM. In scrape-loaded HeLa cells, both globin-targeted and HBV-targeted S-DNAs (both antisense and control oligos) generally failed to achieve significant translational inhibition at extracellular concentrations up to 3000 nM. In contrast, the Morpholino oligos achieved effective and specific translational inhibition at extracellular concentrations ranging from 30 nM to 3000 nM.

Animals↗
PubMed1996

Resistance of morpholino phosphorodiamidate oligomers to enzymatic degradation.

Oligomers possessing the Morpholino phosphorodiamidate backbone were evaluated for resistance to a variety of enzymes and biologic fluids. A 25-mer was incubated with nucleases, proteases, esterases, and serum, and the reaction mixtures were directly analyzed by MALDI-TOF mass spectrometry. The 25-mer was completely resistant to 13 different hydrolases and serum and plasma. The excellent resistance of Morpholino phosphorodiamidates to enzymatic attack indicates their suitability for in vivo use.

Blood Physiological Phenomena↗
PubMed1993

[Seronegative synovitis syndrome].

3 cases of seronegative synovitis syndrome were reported. Two elderly women and one man presented with symmetrical polysynovitis of acute onset involving most of their appendicular joints and flexor digitorum tendons associated with pitting edema of the dorsum of both hands and both feet. Rheumatoid factor was absent from serum samples in all and no radiologically evident erosions developed. All the three patients had a benign course and the disease resolved completely within 2-18 months after the onset. None had deformities, erosions and/or relapse after being followed for 22-34 months. Literatures on this syndrome were reviewed.

Aged↗
PubMed1992

Stacking interactions of ApA analogues with modified backbones.

CD spectra have been measured as a function of temperature for a number of ApA analogues with modified backbones. Oligonucleotides with these modified backbones are being used as antisense agents having potential as viral therapeutics. Results of these studies show that when a carbonyl is substituted for the phosphate to produce an uncharged backbone, the analogues that have either sugar or morpholino substitution do not stack. In contrast, when a morpholino group is substituted for the sugar and the phosphate is modified so as to be uncharged, there is strong base stacking. Stacking interactions in the phosphorus-linked morpholino analogues are at least as strong as those found in d(ApA). The stacking interactions in ApA are weak by comparison. Singular value decomposition demonstrates that the stacking is two state, and Taylor series decomposition yields a coefficient that measures base stacking interactions. The van't Hoff equation is applied to the base stacking coefficient from the Taylor series fitting to give thermodynamic parameters.

Circular Dichroism↗
PubMed1992

Calibration of bone mineral and heavy metal measurements using doped wall-less gel phantoms of arbitrary form.

Cylindrical gel phantoms of 2% agarose concentration were used as wall-less phantoms of arbitrary shape for calibration purposes in non-destructive measurements of bone mineral and heavy metal concentration using XRF. The counts of the coherently and incoherently scattered photons with no sample present should be subtracted as "background" to get a linear relationship between the ratio of the coherently and incoherently scattered photons and the bone mineral concentration for phantoms of arbitrary diameters.

Bone Density↗