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Biomedical subjects

S X Wang

Publications and source records attributed to S X Wang.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Pharmacokinetics and pharmacodynamics of two morphologically homogenous forms of famotidine per os in Chinese healthy volunteers].

The lg C of famotidine (Fam) A and B forms in plasma vs time curve following a single oral dose of 40 mg showed an one-compartment open model in 5 healthy volunteers. The T1/2Ke of Fam A and B forms = 3.06 and 3.48 h, Tmax = 2.96 and 2.68 h, The Cmax = 115 and 145 ng.ml-1, AUC = 811 and 1190 h.ng.ml-1, respectively. No significant difference was found in the pharmacokinetic and pharmacodynamic properties between Fam A and B forms. The mathematical model describing the whole course of blood concentration of Fam A and B forms in relation to inhibiting effects on gastric acid were: E (A) = 100.C2.04/(C2.04 + 15.0(2.04)) and E (B) = 100.C1.67/(C1.67 + 14.0(1.67)). Predication of blood drug concentration from pharmacodynamics or vice versa became possible using the mathematical equations.

Administration, Oral↗
PubMed1993

[Determination of cefixime in human plasma and urine using high performance liquid chromatography column switching technique].

A double column and double pump HPLC switching system is described for the analysis of cefixime in human plasma and urine. The system used muBondapak C18 short pretreatment column for on-line sample clean-up and a Hitachi GEL 3056 (ODS) analytical column for separation. A mixed solution of 0.01 mol/L H3PO4-0.1 mol/L KH2PO4-H2O (20:1:79) was used as the pretreatment mobile phase and CH2CH-0.01 mol/L H3PO4-0.1 mol/L KH2PO4-H2O (13:20:1:66) was used as analytical mobile phase. The compound in plasma and urine is detected by ultraviolet absorption at 286 nm and 314 nm, respectively. The absolute recoveries of the method in plasma and urine were 99.1% and 98.6% respectively. The relative standard deviations of the method are 0.70-3.82% and 0.80-3.73% in plasma, 1.53-3.08% and 1.31-2.67% in urine between days and day-to-day. Linear calibration curve for cefixime was measured over the range of 0.1-3.2 micrograms/ml in plasma and 1.0-32.0 micrograms/ml in urine, and the correlation coefficients were all 0.9999. The detection limit was 0.05 micrograms/ml in plasma and 0.2 micrograms/ml in urine. The plasma and urine samples were diluted with water and injected directly onto the HPLC system. The operation is simple and the relative sensitivity is markedly increased because of higher recoveries and larger loading capacity of the sample.

Cefixime↗
PubMed1993

SC-49518 enhances gastric emptying of solid and liquid meals and stimulates gastrointestinal motility in dogs by a 5-hydroxytryptamine4 receptor mechanism.

SC-49518 (N-[exo-(hexahydro-1H-pyrrolizine-1-yl)methyl]-2-methoxy-4- amino-5-chlorobenzamide HCl), a new benzamide gastrointestinal prokinetic compound, was investigated to determine its ability to stimulate gastrointestinal motility in vivo and whether these actions could be mediated by agonist activity at the putative 5-hydroxytryptamine (5-HT)4 receptor. In conscious fasted dogs with strain gauge transducers and myoelectrodes, SC-49518 disrupted gastric and small intestinal migrating motility complex cycling for more than 3.5 hr. It stimulated gastric antral contractile and intestinal myoelectric spike burst activities during the normally quiescent Phase I of the migrating motility complex at doses as low as 0.01 and 0.03 mg/kg i.v., respectively. In a canine model of gastroparesis, SC-49518 reversed completely alpha-2 adrenergically delayed gastric emptying of a solid meal with an ED50 value of 0.1 mg/kg intragastrically and partially reversed delayed emptying of a liquid meal. SC-49518, like 5-HT, cisapride and renzapride, acted as an agonist (EC50 = 6.6 +/- 1.1 x 10(-8) M) at the putative 5-HT4 receptor in rat esophageal tunica muscularis mucosae by relaxing carbachol-induced contractions. SC-49518 was a partial agonist at 5-HT4 receptors, but also blocked high affinity (5-HT4-mediated) responses to 5-HT (10(-9) M to 3 x 10(-7) M) in guinea pig ileum with a pA2 value of 8.39.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Synthesis, characterization, and antibacterial activity of transition metal complexes with 5-hydroxy-7,4'-dimethoxyflavone.

Complexes of CuII, NiII, CoII, ZnII, FeIII, CrIII, CdII, and MnII with the natural product 5-hydroxy-7,4'-dimethoxyflavone have been synthesized and the probable structures of these complexes have been proposed on the basis of elemental analyses, molecular weight determination, magnetic moments, and electronic and IR spectral data. The presence of coordinated and crystal water molecules was demonstrated by thermal studies. The antibacterial activity of the ligand and all the complexes has been determined on gram positive and gram negative bacteria.

Apigenin↗
PubMed1992

[Studies on anthraquinones from the roots of rubia cordifolia l].

Seven anthraquinones were isolated from the ethyl alcohol extracts of the roots of Rubia Cordifolia L. By means of spectrometric data combined with physico-chemical properties, six of them were identified as 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone (I), 1-hydroxy-9,10-anthraquinone(II), 1,2,4-trihydroxy-9,10-anthrequinone(III), 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-beta-D-glucoside(IV), 1,2-dijhydroxy-9,10-anthraquinone-2-O-beta-D-xylosyl(1-->6)-beta-D -glucoside(V) and 1,3-dihydroxy-2-hydroxymethyl1-9,10-anthraquinone-3-O-beta-D- xylosyl(1-->6)-beta-D-glucoside(VI). VII is a new compound. Its structure was elucidated to be 2-methyl-1,3,6-trihydroxy-9,10-anthraquinone-3-O-beta-D-xylosyl(1-->2)-b eta-D- (6'-O-acetyl)glucoside.

Anthraquinones↗
PubMed1992

[Studies on naphthoic acid esters from the roots of Rubia cordifolia L].

Four naphthoic acid esters including a new compound were isolated from the roots of Rubia cordifolia L. The new one was named as rubilactone and its structure was elucidated as 3'-carbomethoxy-4'-hydroxy-naphtho[1',2'-2,3] pyran-6-one (I) based on the physicochemical properties and spectrometric analyses (UV, IR, MS, 1HNMR and 13CNMR). The other three were 3'-carbomethoxy-4'-hydroxy-naphtho [1',2'-2,3] furan (II), dihydromollugin (III) and 3-carbomethoxy-2-(3'-hydroxy)isopentyl-1,4-naphthohydroquinone-1-O -beta-D-glucoside (IV).

Drugs, Chinese Herbal↗
PubMed1992

[Absorption of ceftizoxime from peritoneal dialysate and its pharmacokinetics in chronic kidney failure patients].

The pharmacokinetics of ceftizoxime (Cef) and its diffusivity across the peritoneal membrane were studied in 10 chronic kidney failure patients undergoing continuous ambulatory peritoneal dialysis. Cef was determined by HPLC. The results showed that the disposition of Cef could be described with a 2-compartment open model after 1 g intravenous infusion. VD = 20 +/- 5 L, AUC = 1237 +/- 327 micrograms.ml-1.h. T1/2 beta = 16.9 +/- 4.5 h, which was much longer than that of patients with normal renal function. Therefore, the regulation of dose regimen was necessary when treating patients with renal failure. Cef was partly eliminated by peritoneal dialysis with the ClD of 2.9 +/- 1.0 ml.min-1. The bidirectional exchange of Cef was seen between blood and dialysate. It is more suitable to describe the diffusive characteristics of Cef from dialysate (or blood) into blood (or dialysate) with a zero order constant rate model. The absorption percentage of Cef after 0.5 g instilled with peritoneal dialysate was 90.4 +/- 7.0%.

Absorption↗
PubMed1992

[Determination of captopril in plasma and urine by high-performance liquid chromatography with column switching].

A rapid and sensitive column-switching high performance liquid chromatographic procedures was described for determination of captopril in plasma and urine. p-Bromophenacyl bromide, a derivatizing reagent, was added to the plasma and urine samples to form an adduct which showed ultraviolet absorbing properties. After that, the urine sample was injected directly and for plasma the protein was removed with 6% of perchloride before injection. The column-switching system was equipped with a pre-column of 5 cm x 0.5 cm ID, packed with mu Boundapak C18, 37-50 microns, and an analytical column of 15 cm x 0.5 cm ID, packed with YWG-C18, 10 microns. After washing out the impures from pre-column with 0.2% acetic acid the retained substances were eluted into analytical column with acetonitrile-water-acetic acid (35:65:0.4). Captopril was detected at 260 nm. The method was linear within 20-1000 ng/ml for plasma and 10-200 micrograms/ml for urine. The recovery averaged 103.2% and 99.5% for plasma and urine, respectively. The coefficient variations were all less than 10%.

Captopril↗
PubMed1991

Cholecystokinin-mediated ileal electrolyte transport in the guinea pig. Characterization of receptor subtype.

Cholecystokinin (CCK) receptors are currently divided into at least two subtypes: a CCK-A subtype, responsive to the sulfated form of cholecystokinin octapeptide (CCK-8) and selectively antagonized by L-364,718, and a CCK-B subtype, which shares equal affinities for gastrin and CCK-8. In the present study the receptor subtype that mediates guinea pig ileal secretion by evaluating the potencies of CCK- and gastrin-related peptides to evoke increases in transmucosal short-circuit current was characterized. The antagonist potencies of L-365,260 (CCK-B selective) and L-364,718 (CCK-A selective) against CCK-8 were also determined. Both CCK-8 and cerulein, when added to the serosal side of the tissue, evoked increases in the short-circuit current, having EC50 values of 0.8 and 0.2 nmol/L, respectively. Desulfated (SO3) CCK-8, CCK-4, gastrin17-I, pentagastrin, gastrin17-II, and gastrin13-I were relatively weak agonists (EC50 greater than 1000 nmol/L. Cholecystokinin octapeptide-induced short-current responses were competitively antagonized by L-364,718 (pA2, 10.3) and L-365,260 (pA2, 7.4). The high selectivity of the tissue for sulfated CCK-8 suggests that the secretory effect of CCK-8 on guinea pig ileal electrolyte transport is mediated by a CCK-A receptor. The potent effect of L-364,718 against CCK-8 is also consistent with an action at the A-subtype receptor.

Animals↗
PubMed1991

Induced abortion in eight provinces of China.

A survey of 12,000 women in eight provinces of China was carried out in 1988. One urban and one rural area were selected purposely in each province; data on lifetime and recent pregnancies were collected from married women aged 20-44. Data on abortions included reasons, gestational age, and complications. During the five years before the survey, the number of abortions per 100 live births was 102 in urban areas and 62 in rural areas. For those with one or more previous live births in urban areas, nearly all subsequent pregnancies ended in abortion. Also in urban areas, 31% of women with a recent abortion reported the reason was contraceptive failure. Over 80% of women are contraceptive users; the high abortion rates then reflect relatively low use-effectiveness of contraception and that most unplanned pregnancies are aborted.

Abortion, Induced↗
PubMed1991

Pharmacokinetics and bioavailability of famotidine in 10 Chinese healthy volunteers.

The pharmacokinetics and bioavailability of famotidine were investigated by HPLC method in 10 Chinese healthy volunteers. Data obtained from HPLC were analysed automatically using a MCPKP program on microcomputer. Linear pharmacokinetics were observed following either iv or po administration. After 20 mg iv, plasma levels declined biexponentially with an initial T1/2 of 0.3 +/- 0.2 h and terminal T1/2 of 3.5 +/- 0.8 h. The plasma elimination T1/2 following po administration were 3.4 +/- 0.7 h and 3.5 +/- 0.5 h for capsules and tablets respectively. Oral absorption was incomplete. The absolute bioavailabilities were 38 +/- 10% for capsules and 43 +/- 11% for tablets. Renal excretion was the major route of elimination. About 72% of the dose were recovered as unchanged famotidine in urine. Mean renal and plasma clearance were 416 and 541 ml.min-1 respectively.

Adult↗
PubMed1991

[Changes in T-lymphocyte subsets in patients with orthopedic trauma and effects of yipanzhu decoction on the impaired immune function].

The effects of yipanzhu decoction (YD) on immune function in 40 patients [2 groups, YD and normal saline (NS) group] with orthopedic trauma by taking T lymphocyte subsets as indexes were observed. The peripheral venous blood samples randomly taken from 30 healthy subjects served as control. The blood were collected within 24 hours after trauma. Then the YD and NS were respectively given to the patients in the 2 groups for 3 days, and the blood were taken 4th, 7th, 14th day after trauma for the observation of T subsets. The results revealed that before administration of YD the percentage of pan-T cells was reduced with an increased percentage of Ts cells and a decreased ratio between Th and Ts cells; 3 days after giving the drugs in YD group the percentage of pan-T cells was slightly increased, and the changed percentage of Ts cells and the ratio of Th/Ts cells mentioned above was recovered to normal, while in NS group all these indexes remained at abnormal range during the period we observed. The results suggested that YD could promote the recovery of abnormal T lymphocyte subsets in traumatized patients, and it possessed to some extent the function of immune regulation that was helpful to reduce the ratio of infection after trauma.

Adolescent↗
PubMed1990

Effectiveness of phenol-atabrine-paste (PAP) instillation for female sterilization.

Two groups of sterilized women, 3307 by phenol-atabrine-paste (PAP) instillation and 1026 by mini-lap technique, were follow-up interviewed to determine their relative effectiveness. PAP, if successfully performed, was as effective as the mini-lap. The life table pregnancy rates among successful PAP women were 0.21 and 0.28 at 12 and 24 months, respectively. The rates among the unsuccessful PAP women, however, were high: 15.1 and 30.5 at 12 and 24 months, respectively. In spite of its distinctive advantage of being non-surgical, wider promotion of PAP sterilization procedure deserves caution.

Adult↗
PubMed1990

[Studies on antibacterial constituents from the roots of Rubia cordifolia L].

Twelve compounds were isolated from the roots of Rubia cordifolia L.. Nine of them were established by chemical and spectroscopic methods to be alizarin (I),1-hydroxy-2-methyl-9,10-anthraquinone(II),1,3,6-trihydroxy-2-methyl- 9,10-anthra-quinone-3-O-(6'-O-acetyl)-alpha-L-rhamnosyl(1--- -2)-beta-D- glucoside(III),1,3,6-trihydroxy-2-methyl-9,10-anthraqueinone-3-O-a lpha- L-rhamnosyl(1----2)-beta-D-glucoside(IV),1,3,6-trihydrozy-2- methyl-9,10- anthraquinone-3-O-(6'-O-acetyl)-beta-D-glucoside(V),2-carbomethyoxy++ +-3-prenyl- 1,4-naphthohydroquinone di-beta-D-glucoside(VI),rubimallin(VII),beta- sitosterol(VIII) and daucosterol(IX), among them, V is a nwe compound and IX was obtained from this genus for the first time, III, VI and VII showed certain antibacterial activities.

Anthraquinones↗
PubMed1990

[Alpha 1-antitrypsin in clinical diagnosis of primary hepatic carcinoma--an appraisal of monoclonal antibody-rate nephelometry].

This study was undertaken to evaluate the use of serum alpha 1-antitrypsin (alpha 1AT) in clinical diagnosis of primary hepatic carcinomas with monoclonal antibody-rate nephelometry. BALB/c mice were injected with human alpha 1AT. Spleen cells of the immunized mice and SP2/0 myeloma cells were hybridized in vitro. Monoclonal antibodies against alpha 1AT so obtained were used as detection agents in immuno-chemical monitor system (ICS). In 50 healthy individuals, serum alpha 1AT was 209 +/- 46.04 mg/dl. Serum alpha 1AT was determined in 49 patients with primary hepatic carcinoma, 26 with chronic active hepatitis and 26 with cirrhosis. Their positive rates were 43%, 3.8% and 0, respectively. Serum alpha 1AT level was significantly higher in primary hepatic carcinoma than in chronic active hepatitis and cirrhosis patients (P less than 0.001). No difference was found in alpha 1AT between patients with benign liver diseases and healthy adults (P greater than 0.05). The results indicate that alpha 1AT is useful in the diagnosis of primary hepatic carcinomas.

Animals↗
PubMed1989

Contribution of the intestine to the first-pass metabolism of felodipine in the rat.

The systemic availability of intraduodenally (i.d.) administered felodipine in the rat is about 10%. The purpose of this study was to determine to what extent intestinal metabolism contributes to the first-pass elimination of felodipine in the rat. Four different types of experiments were performed. 1) [3H]Felodipine was given i.v. and i.p.; 2) the uptake of i.p. administered [3H]felodipine by the lymph was studied for 3 hr after dosing; 3) portal blood was collected quantitatively for 40 min after i.d. administration of [3H]felodipine; and 4) the in vitro metabolism of felodipine was studied in intestinal cell suspensions. The mean bioavailability of the i.p. dose was approximately 48%. The uptake via the lymph was negligible as an insignificant amount of the radioactive i.p. dose was recovered in lymph from a main lymph vessel in the peritoneal cavity. An average of 21 +/- 12% of given radioactive dose was recovered in portal blood during the first 40 min after i.d. dosing. The recovered radioactivity was to 40 to 70% due to felodipine and 9 to 16% was due to dehydro-felodipine. These results indicate that substantial first-pass elimination occurs in the intestine of the rat. Further support for gastrointestinal metabolism of felodipine in the rat was obtained from incubations with intestinal cells.

Animals↗