Correction of a defect in mammalian GPI anchor biosynthesis by a transfected yeast gene

Glycosylphosphatidylinositol (GPI) serves as a membrane anchor for a large number of eukaryotic proteins. A genetic approach was used to investigate the biosynthesis of GPI anchor precursors in mammalian cells. T cell hybridoma mutants that cannot synthesize dolichol-phosphate-mannose (Dol-P-Man) also do not express on their surface GPI-anchored proteins such as Thy-1 and Ly-6A. These mutants cannot form mannose-containing GPI precursors. Transfection with the yeast Dol-P-Man synthase gene rescues the synthesis of both Dol-P-Man and mannose-containing GPI precursors, as well as the surface expression of Thy-1 and Ly-6A, suggesting that Dol-P-Man is the donor of at least one mannose residue in the GPI core.

[Protective action of Salvia miltiorrhiza aqueous extract on chemically induced acute myocardial ischemia in rats]

Aqueous extract of Salvia miltiorrhiza (SM-H) can protect the acute myocardial ischemia and arrhythmia of Sprague-Dawley rats induced by isoproterenol (ISO) or BaCl2 with the following results: (1) intraperitoneal injection (i.p.) of SM-H for 3 to 5 days or intravenously (i.v.) just once significantly reduced the death rate of the animals, (2) i.v. SM-H pretreatment significantly increased the lethal dose of BaCl2 infusion, (3) i.p. SM-H significantly decreased premature ventricular contraction, ventricular fibrillation, bradycardia and mortality rate induced by bolus i.v. of BaCl2, and (4) i.p. SM-H also significantly reduced ECG J-point displacement of rats induced by ISO.

Sufentanil, morphine, met-enkephalin, and kappa-agonist (U-50,488H) inhibit substance P release from primary sensory neurons: a model for presynaptic spinal opioid actions

An in vitro model system for analysis of presynaptic inhibitory actions of spinal opioids has been applied. Embryonic sensory neurons derived from chick dorsal root ganglia were grown in primary cell culture, and the release of substance P was evoked by electrical field stimulation during exposure to drugs with well-demonstrated affinity for opioid receptors. This allowed a pharmacologic characterization of the inhibitory actions of specific opioid agonists on the release of substance P as measured by radioimmunoassay (RIA). Sufentanil (0.5 microM), a high affinity mu receptor agonist, U-50,488H (25 microM), a selective kappa receptor agonist, and morphine (10 microM), an agonist with high affinity for mu and delta receptors, inhibited the evoked release of substance P by approximately 60%, 40%, and 50%, respectively. For sufentanil the response was demonstrated to be dose-dependent. As is the case for its analgesic action in vivo, morphine was approximately 50-fold less potent than sufentanil on a molar basis in this assay. The actions of sufentanil, U-50-488H and morphine were mimicked by the endogenous opioid peptide met-enkephalin, and its stable synthetic analog D-ala2-met5-enkephalinamide (DAME). Naloxone (25 microM), an opioid receptor antagonist, blocked the inhibitory action of sufentanil (0.5 microM), morphine (5 microM), and DAME (5 microM), but not U-50,488H (10 microM). The action of U-50,488H was partially blocked by the antagonist naltrexone (25 microM). Stereo-selectivity of agonist action was confirmed by the failure of dextrorphan (50 microM), an inactive opioid isomer, to inhibit the release of substance P.(ABSTRACT TRUNCATED AT 250 WORDS)

Quaternary Alkaloids of Tinospora capillipes

Extracts of the roots of TINOSPORA CAPILLIPES Gagnep. (Menispertnaceae) afforded the quaternary protoberberine alkaloids palmatine, jatrorrhizine, columbamine, stepharanine and dehydrodiscretamine and the quaternary aporphine alkaloids menisperine and magnoflorine.

New Oleanene-type Triterpenes from Abrus precatorius and X-ray Crystal Structure of Abrusgenic Acid-Methanol 1:1 Solvate

From ABRUS PRECATORIUS Abl. triterpenoids abruslactone, methyl abrusgenate and abrusgenic acid were isolated and elucidated by spectroscopic and X-ray techniques.

Isolation and structural elucidation of some sapogenols from Abrus cantoniensis

After hydrolysis of the saponin fraction of the roots of Abrus cantoniensis, a new triterpenoid sapogenol, cantoniensistriol, was isolated together with sophoradiol, soyasapogenol B and soyasapogenol A. The structures of cantoniensistriol and sophoradiol were elucidated by spectroscopic methods. On the basis of the relation between cantoniensistriol and soyasapogenol A, the steric assignment of the C-21 and C-22 hydroxyl groups of the latter was discussed.

Effects of Fructus gardeniae extract on hepatic function

This article discusses the effects of Fructus Gardeniae extract on hepatic function. Fructus Gardeniae extract manifested no hepatotoxic effects on rats, as shown by alkaline phosphatase, aspartate aminotransferase, and lactate dehydrogenase studies. Fructus Gardeniae extract failed to activate the UDP-glucuronyltransferase system; whereas in hyperbilirubinemic state the enzyme was activated, presumably by substrate induction. Fructus Gardeniae extract increased the activity of UDP-glucose dehydrogenase, which would result in an increase in availability of UDP-glucuronic acid intracellularly, BSP clearance study showed an unexpected impairment of hepatic uptake of the dye after extract treatment. The action mechanism involved in lowering of serum bilirubin level by Fructus Gardeniae extract may well be complex; it is probably acting on a locus other than glucuronyl transferase.