Biomedical subjects
Publications and source records attributed to S C Ma.
Two furanoditerpenoid lactones, were isolated from the seeds of Caesalpinia minax Hance. Their structures and stereochemistry have been established by spectral data and single crystal X-ray analysis.
A bioassay-guided study led to the isolation of five new cassane furanoditerpenes, designated as caesalmin C (1), D (2), E (3), F (4), and G (5), along with stigmasterol (6) from the seeds of Caesalpinia minax. The (1)H and (13)C NMR spectra were completely assigned by using a combination of 2D NMR analyses. The structures of all five furanoditerpenes were confirmed by X-ray analyses. The structure of 6 was verified by X-ray analysis for the first time. The bioassay results showed that the anti-Para3 virus activity of tetracyclic furanoditerpenoids 1-4 is more potent than that of the furanoditerpenoid lactone 5, which is in turn better than 6. As the major components of the plant possess significant potent activity, it may be feasible to develop new antiviral agents from this source.
Amentoflavone and three other flavonoids were isolated from the ethanol extract of Selaginella sinensis. Amentoflavone showed potent antiviral activity against respiratory syncytial virus (RSV), with an IC50 of 5.5 microg/ml. The contents of amentoflavone in nine species of Selaginella were determined by reversed-phase HPLC. S. sinensis showed a higher content of 1.13%.
Mikanin-3-O-sulfate (1), in the form of its potassium salt, together with mikanin (2) and alpinetin (3) were isolated from Mikania micrantha. The crystal structures of K(1) x CH3OH, 2 and 3 x H2O were established by X-ray crystallography. The potassium ions in K(1) x CHO3H are bridged by O5, O7 and O8 to form a chain of face-sharing KO8 coordination polyhedra, from which the aglycon units are outstretched to form a polymeric molecular column. Adjacent molecular columns are linked by pi-pi stacking between parallel, intercalating aglycon units to form layers matching the (101) family of planes, which are further interconnected into a three-dimensional supramolecular assembly. Sulfation at 3-OH induced better co-planarity and conjugation of the rings.
Six secoiridoid glucosides, lucidumoside C (1), oleoside dimethylester (2), neonuezhenide (3), oleuropein (4), ligustroside (5) and lucidumoside A (6), isolated from the fruits of Ligustrum lucidum (Oleaceae), were examined in vitro for their activities against four strains of pathogenic viruses, namely herpes simplex type I virus (HSV-1), influenza type A virus (Flu A), respiratory syncytial virus (RSV) and parainfluenza type 3 virus (Para 3). Antiviral activities were evaluated by the cytopathic effect (CPE) inhibitory assay. The purpose was to check if the antioxidative potency of these glucosides correlated with their antiviral potency. Results showed that none of the glucosides had any significant activity against HSV-1 and Flu A. Oleuropein, however, showed significant antiviral activities against RSV and Para 3 with IC50 value of 23.4 and 11.7 microg/ml, respectively. Lucidumoside C, oleoside dimethylester and ligustroside showed potent or moderate antiviral activities against Para 3 with IC50 values of 15.6-20.8 microg/ml. These results also documented that the anti-oxidative potency of these secoiriodoid glucosides was not directly related to their antiviral effects.
A multifunctional peritoneal biopsy needle is introduced in this paper, which can be used for peritoneal biopsy, brush biopsy and routine, biochemical and cytological examination. The clinical applications show that it could raise markedly the diagnosis rate of ascites, and especially it has important clinic diagnosis value for tuberculous and cancer ascites, and primary peritonitis complicated by hepatocirrhosis. It is simple, safe and practical to operate this needle.
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A unique and simple colorimetric method for the quantitation of plasma protamine levels has been developed. The method is established on the competitive binding displacement mechanism between protamine and heparin-azure A dye complex, and the metachromatic color change of azure A dye in the presence of heparin. Because the method is based on the clinical specificity of protamine as the heparin antagonist, it is specific for protamine quantitation. Plasma protamine levels determined by this method are within 94% of accuracy when compared with their aqueous counterparts determined by the conventional Lowry protein assay. Since the method measures the protamine excess after heparin neutralization, it potentially could be employed during clinical heparin reversal with protamine to monitor protamine excess. In addition, the method may provide a useful means to identify the mechanism of the so-called "heparin rebound".
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Further studies regarding the potentiometric response to heparin of polymeric membranes doped with lipophilic quaternary ammonium salts are reported. Among a wide range of membrane formulations examined, optimum response toward macromolecular heparin is achieved using tridodecylmethylammonium chloride as the active membrane component within poly(vinyl chloride) or poly(vinyl chloride)/(vinyl acetate) films plasticized with dioctyl sebacate. Although such membranes are shown to exhibit a typical Hofmeister potentiometric selectivity pattern toward small inorganic and organic anions, a very large and reproducible response to heparin at submicromolar levels is observed in the presence of physiological saline (0.12-0.15 M NaCl), as well as in citrated whole blood. Equal response on a mass basis occurs with fragments of heparin's as small as 2500 Da. Complexation of heparin's anionic sites by macromolecules that bind heparin with high affinity (e.g., protamine and poly(L-lysine)) reduces the membrane electrode's heparin response, indicating that the electrode detects biologically available (unbound) heparin levels in solution. Quantitative potentiometric titrations of protamine with porcine mucosa heparin followed by the sensor yield stoichiometric values in good agreement with the literature. The biomedical utility of the sensor is demonstrated by measuring its response in whole blood from patients undergoing open heart surgery before and after heparin therapy and correlating such response to conventional blood clotting time measurements.
Recent progress in the design of new polymer membrane-based potentiometric ion-, gas- and bio-selective electrodes in chemistry laboratories at the University of Michigan (Ann Arbor) is reviewed. Emphasis is placed on describing the performance of devices for measuring anions (e.g., salicylate, thiocyanate, chloride and heparin) and gases (e.g., ammonia, carbon dioxide and oxygen) in biological samples, both in vitro and in vivo. Beyond direct measurement of key ions and gases in complex matrices, some of the new membrane electrode systems reported can serve as base transducers for the development of biosensors containing integrated biological reagents, including enzymes and antibodies. New approaches for mass fabricating solid-state ion and biosensor devices as well as future directions for research in the entire field of polymer membrane sensors are also described.
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3,4-Dichloro-N-methyl-N-[trans-2-(1-delta 3-pyrrolinyl)-cyclohexyl] benzenacetamide hydrochloride (K-II) is a novel analogue of U-50488H. Previous studies have demonstrated that K-II is more potent than U-50488H in analgesic activity in mice and in inhibitory effect on electrically induced contractions of the isolated rabbit vas deferens. In this paper, we determined the affinities of K-II and U-50488H for kappa opiate receptor in guinea pig cerebellum and frontal cortex using radioreceptor binding assay (saturation studies and competition studies), and calculated Ki values of K-II and U-50488H by the Cheng-Prusoff equation. The results indicate that the affinity of K-II for kappa opiate receptor is 6-42 times greater than that of U-50488H. The selectivity of K-II for opiate receptor subtypes is being studied.
In this paper, we report the synthesis and analgesic activities in mouse hot plate test and writhing test of some analogs of U-50488, a kappa-agonist. Results showed that compounds in which the amino group was pyrrolinyl had higher kappa-agonist activity and the substitution of two chlorine atoms in 3 and 4-positions of the benzene nucleus was very important to kappa-activity. Furthermore, all of compounds in which the amino group was piperidyl, piperazinyl or morpholinyl exhibited very weak kappa-agonist activity.
K-II is an analogue of U-50488, a selective kappa-opioid agonist. Comparison of pharmacological profile of K-II and U-50488 was studied using in vitro and in vivo methods. The results showed that the IC50 values of K-II and U-50488 on electrically induced contraction of the rabbit vas deferens were 0.42 nmol/L and 26.5 nmol/L, respectively. ED50 values of K-II and U-50488 in impairing motor function of mouse in the horizontal screen test were 1.7 and 15.3 mg/kg, respectively. The effect of K-II in reducing spontaneous activity of mouse was 6 times as potent as U-50488. These results suggest that K-II is a more potent kappa agonist in pharmacological effects than U-50488.
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