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Biomedical subjects

J J Sun

Publications and source records attributed to J J Sun.

At least 19 recordsLinked to original sources
PubMed1999

Invasion and metastasis of liver cancer: expression of intercellular adhesion molecule 1.

PURPOSE: To study the relationship between intercellular adhesion molecule 1 (ICAM-1) and liver cancer metastasis and to find predicting factors that could indicate the growth and metastasis of liver cancer. METHODS: ICAM-1 expression in fresh tissue of normal liver and hepatocellular cancer (HCC) was examined by immunoperoxidase staining. Serum soluble intercellular adhesion molecule 1 (sICAM-1) from patients with a benign HCC tumor, and the expression of ICAM-1 in the orthotopically transplanted LCI-D20 tumor of a nude mouse liver cancer metastasis model, and in human hepatoma, the tumor surrounding tissue and normal liver, was analyzed semiquantitatively by the immuno-dot blot method. Tissue ICAM-1 expression (mRNA level) was detected by Northern blotting. RESULTS: ICAM-1 expression in LD1-20 D metastatic liver cancer had a positive correlation with tumor size and the time after implantation. It increased suddenly as metastasis occurred being 3.03+/-0.51 before metastasis and 8.24+/-0.95 after metastasis, P < 0.01, then remained high, appending on the number of sites involved (monosite metastasis 5.48+/-0.49, multisite metastasis 10.05+/-1.17, P < 0.05). All six cases of normal liver samples were negative in anti-ICAM-1 immunohistochemical staining, 80.0% (36/45) of the HCC showed some ICAM-1 expression. The rate of positive cells was a little higher in large tumors, tumors with an intact capsule and tumors with metastasis, but there was no significant difference. It was noticed that two cancer emboli also had high ICAM-1 expression. The ICAM-1 concentration in HCC (13.43+/-0.09) was higher than that in tumor surrounding the liver (5.89+/-0.17, P < 0.01) and that in normal liver (4.27+/-0.21, P < 0.01). sICAM-1, like tissue ICAM-1, was higher in HCC patients than in patients (with benign liver tumor and normal controls. Both tissue ICAM-1 and sICAM-1 were higher in the metastasis group than in the group without metastasis (tissue ICAM-1 20.24+/-0.30 vs 10.23+/-0.12 P < 0.05; sICAM-1 12.18+/-0.25 vs 9.77+/-0.54 P < 0.05). Northern blot analysis revealed that ICAM-1 expression, as indicated by mRNA level, was also higher in HCC and in cancer emboli than in tumor surrounding liver and normal liver. CONCLUSIONS: Tissue ICAM-1 and serum sICAM-1 could indicate the stage of HCC, and the potential of hepatoma cells for invasion and metastasis. They may play an important role in the metastasis cascade.

Animals↗
PubMed1999

Alterations of T-lymphocyte subsets, soluble IL-2 receptor, and IgE in peripheral blood of children with acute asthma attacks.

BACKGROUND: T-cell activation and alteration of cytokines are involved in the pathogenesis of atopic asthma. However, the profile of circulating T-lymphocyte subsets, related cytokines, and plasma IgE during acute asthma attacks is still unclear. OBJECTIVE: In an attempt to illustrate the dynamics of these parameters in asthma attacks, we investigated the changes of T-cell subsets, lymphocyte activation, soluble IL-2R, and IgE in peripheral blood in children during and after acute asthma attacks. METHODS: This study was carried out in a cohort of Chinese children (n = 59) with acute asthma attacks. Immunoassays were performed when the patients had acute attacks before treatment, and the patients were reexamined in the 4 weeks after the resolution of acute attacks with therapy. Paired t tests were used for the statistical analysis of these patients to compare the data obtained during and after the acute attacks. Twenty healthy, age-matched subjects were used as normal control subjects. Nine children with long-term stable asthma were used as control subjects with stable asthma. RESULTS: CD3+, CD4+, CD8+, and IL-2R+ (CD25+) cells; plasma soluble IL-2 receptor; and IgE were significantly higher in patients with acute attacks than in control subjects. (P <.05, P <.05, P <.001, P <.05, P <.0001, and P <.0001, respectively). Immunoelectron microscopy exhibited an increased expression of IL-2R on lymphocytes in acute attacks as compared to control subjects. The abnormalities returned to normal, with the exception of IgE, when clinical remission was achieved after treatment. Correlation analyses revealed a positive relationship between plasma IgE and soluble IL-2R in asthma attacks (r = 0.83, P =.0001). Plasma IgE and soluble IL-2R of those who were in remission positively correlated with their production in acute attacks (r = 0.58, P =.001 and r = 0.71, P =.0001, respectively). CONCLUSION: This study suggests that (1) the percentage of CD4+, CD8+, or IL-2R+ lymphocytes in peripheral blood was significantly elevated during acute attacks and returned to normal ranges after complete remission was achieved; (2) plasma soluble IL-2R is a sensitive marker for asthma activity; and (3) atopic asthmatic children seem to have a hereditary predisposition of having higher levels of soluble IL-2R in asthma attacks, coinherited with the trait of IgE.

Acute Disease↗
PubMed1997

Comparison of the Ca2+ movement by activation of alpha1-adrenoceptor subtypes in HEK-293 cells.

We studied the Ca2+ movement induced by activation of alpha1A-, alpha1B- and alpha1D-adrenoceptor subtypes in transfected HEK-293 cells with the fura-2 probe. All these alpha1-AR subtypes induced both Ca2+ release and Ca2+ entry. The effect on Ca2+ release in alpha1b transfected HEK-293 cells was bigger than that in alpha1a and alpha1d transfected HEK-293 cells, and the effects on Ca2+ entry were the same in alpha1a, alpha1b and alpha1d transfected HEK-293 cells. The Ca2+ entry was inhibited by 1 mM NiSO4, but not by nifedipine. Cyclopiazonic acid (CPA) produced a biphasic Ca2+ signal response in Ca2+ medium, and only induced a transient response in Ca2+-free medium. After depletion of CPA-sensitive Ca2+ pool by 10 microM CPA in Ca2+-free medium, 10 microM adrenaline (Adr) still transiently increased [Ca2+]i in three different alpha1-adrenoceptor subtype transfected HEK-293 cells. However, after depletion of adrenaline-sensitive Ca2+ pool by 10 microM Adr, CPA transiently elevated [Ca2+]i only in alpha1a and alpha1d transfected HEK-293 cells, not in alpha1b transfected HEK-293 cells. U73122, a phospholipase C (PLC) inhibitor, inhibited both Ca2+ release and Ca2+ entry induced by activation of alpha1A alpha1B and alpha1D subtypes in transfected HEK-293 cells. These results suggest that HEK-293 cell line contains two functionally separate intracellular Ca2+ pools, CPA-sensitive and Adr-sensitive pools. Activation of alpha1B-AR stimulates Ca2+ release from both CPA-sensitive and Adr-sensitive Ca2+ pools. Alpha1A and alpha1D subtypes induce Ca2+ release only from Adr-sensitive Ca2+ pool.

Animals↗
PubMed1997

Supercritical fluid extraction method development for extraction of an experimental HIV protease inhibitor drug from animal feed.

Supercritical fluid extraction (SFE) was evaluated as a sample preparation procedure for the recovery of experimental drugs from animal feed preparations that are generated during long-term toxicology studies. A commercially available supercritical fluid extractor was utilized to develop and validate an off-line procedure for the recovery of an experimental HIV protease inhibitor drug from animal feed. Extracts were analyzed with a conventional reversed-phase HPLC method. Elements of the SFE method developed that are described include optimization of the system temperature and selection of the extraction media modifier. The study emphasized the performance of two-day precision and accuracy studies. Precision and accuracy studies were carried out with SC-52151 levels of 0.05, 0.1 and 1.0% (w/w) and used an internal standard quantitation format. Also, the study utilized a relatively large analytical scale extraction vessel size of 10 ml to accomodate 6 g animal feed samples.

Animal Feed↗
PubMed1996

Respiratory toxicity of direct lytic factor in the venom of the southern Chinese cobra (N. naja atra) in dogs.

The effects of direct lytic factor (DLF) on respiratory ventilation, gas exchange as well as hemodynamics were studied in anesthetized dogs. After an intravenous DLF dose of 1 mg/kg, the initial manifestation of intoxication was observed as follows: (1) Increase in airway impedance characterized by slowed air flow rate and increased negative transpulmonary pressure. (2) Decrease in dynamic compliance. (3) Progressive increase in venoarterial shunt (Qs/Qt) and decrease in PaO2, (4) Elevation of pulmonary artery blood pressure and fall of mean systemic blood pressure and maximal left ventricular pressure. Above actions reached the peak values at 15 min and thereafter all respiratory functional parameters, except Qs/Qt and hypoxemia, returned gradually to approach the normal levels at 50 min. The tidal volume, PaCO2 and LVEDP remained unchanged until another DLF dose of 1.5 mg/kg was given. After a second dose of DLF (total 2.5 mg/kg), the respiratory functions and the cardiac performance deteriorated as follows: (1) Further increase in Qs/Qt and hypoxemia. (2) Appearance of hypercapnea and acidosis. (3) Fall of dP/dtmax and elevation of LVEDP, widening of QRS complex of ECG. (4) Blood pressure run a downhill course. From above experimental evidence, we came to the conclusion that as well as the basic cardiotoxicity, respiratory toxicity of DLF must be considered as the primary, because of broad spectrum of action of DLF and early effect on respiratory function.

Animals↗
PubMed1996

Synergism of procoagulation effect of thrombin-like enzymes from Dienagkistrodon acutus and Agkistrodon halys snake venoms.

AIM: To study the synergistic effect of thrombin-like enzymes (TLE) of Dienagkistrodon acutus (DA) and Agkistrodon halys (AH) venoms. METHODS: TLE were isolated from venoms of DA and AH by successive column chromatography. Effects of combination of DATLE and AHTLE and related factors on the clotting time and clot quality were tested in vitro. RESULTS: One coagulation unit was 2.7 micrograms for DATLE and 304.4 micrograms, for AHTLE with reference standard of thrombin (42.2 micrograms). TLE-induced clot was a fibrin monomer which was fragile and did not retract. Combination of AHTLE and DATLE shortened the clotting time and decreased the solubility of the clot in urea 5 mol.L-1. When subthreshold concentration of thrombin or physiological concentration of Ca2+ was added, the clotting time was further shortened, the clot was no longer soluble in urea and retracted well, and the resistance of the clot to plasmin degradation was increased. CONCLUSION: A synergistic effect of DATLE and AHTLE accelerated hemocoagulation and improve clot quality.

Agkistrodon↗
PubMed1995

Supercritical fluid extraction-liquid chromatography method development for a polymeric controlled-release drug formulation.

We have recently been involved in the development of a method for assaying the active component in a controlled-release drug formulation, which is composed of a drug substance covalently bonded to polymer matrix. The drug substance in the formulation is the active enantiomer of misoprostol, a synthetic analog of natural prostaglandins and the active ingredient in Cytotec. Our method development consisted of a systematic evaluation of dynamic, off-line supercritical fluid extraction (SFE) as sample preparation for the formulation assay. Extracts were analyzed with normal phase and reversed-phase HPLC methods. The reversed-phase system utilized postcolumn reaction to provide selective detection of the extracted prostaglandin sample components. Several SFE parameters were investigated to optimize the recovery of the drug substance from the formulation, including sample quantity, extraction cell volume, extraction duration, supercritical carbon dioxide modifier, temperature, pressure, and collection solvent. The SFE experiments were completed with a commercially available multicell extractor. Preliminary validation studies utilized a formulation made with radiolabeled drug to determine the recovery achieved under the optimized SFE conditions and assessed the precision of replicate determinations. Analysis was completed under the optimized conditions to quantitate levels of the active component and related compounds in lots of the experimental polymeric formulation and to determine the total weight per cent extracted.

Carbon Dioxide↗
PubMed1994

Protective effect of cobra venom factor on pulmonary injury induced by oleic acid.

The protective effect of cobra venom factor (CVF), separated from the venom of Naja naja atra, on pulmonary injury induced by oleic acid was reported. The blood gas tensions, tidal volume, transthoracic pressure and pulmonary arterial pressure in anaesthetized dogs were continually monitored. The experimental results showed that CVF, given 20 h before the dosage depleting complements exceed 95%, significantly attenuated oleic acid-induced pulmonary dysfunction, including hypoxemia, increasing veno-arterial shunt and P(A-a)O2 and decreasing dynamic compliance and pulmonary blood flow. Histological examination of lung tissues after the experiment also showed improvement of hyaline membrane formation, alveolar haemorrhage and pulmonary arteriolar thrombosis. It was evident that the depletion of serum complements by CVF inhibited the development of lung injury induced by oleic acid. CVF might be a potentially useful drug for the treatment of respiratory distress syndrome in the near future.

Animals↗
PubMed1994

Effects of Panax notoginseng saponins on receptor-operated Ca2+ channels in vascular smooth muscle.

The effects of saponins of Panax notoginseng (PNGS) on the alpha-adrenoceptor agonists-induced contractile responses and Ca2+ movement were studied in dog mesenteric artery (MA) and saphenous vein (SV). PNGS reduced the contractions and the 45Ca influx (from 0.36 +/- 0.03 to 0.14 +/- 0.05 mumol.g-1 wet strip) induced by phenylephrine (Phe) without effect on KCl-induced contraction and 45Ca influx which were nearly completely inhibited by nifedipine 0.1 mumol.L-1. PNGS did not change the 45Ca efflux induced by Phe and the Kd value (from 0.76 +/- 0.04 to 0.72 +/- 0.15 nmol.L-1) for [3H]prazosin binding on the microsomal membrane isolated from MA. Our results indicate that PNGS selectively inhibits Ca2+ entry through receptor-operated Ca2+ channel.

Adrenergic alpha-Agonists↗
PubMed1993

Effects of direct lytic factors from southern Chinese cobra venom on Ca2+ movement in rabbit aorta strip.

The purified direct lytic factors (DLF) from southern Chinese cobra (Naja naja atra) venom induced a contractile response in Ca(2+)-free Krebs' solution and a further increase in the tension following a subsequent addition of Ca2+ into bath. After depletion of intracellular Ca2+ pool by phenylephrine, DLF failed to induce any contractile response. In 45Ca2+ experiments, DLF increased both 45Ca2+ release and 45Ca2+ influx. Procaine 2 mmol.L-1 decreased the DLF induced 45Ca2+ release and 45Ca2+ influx by 67 +/- 23% and 46 +/- 32%, respectively. Nifedipine and verapamil 1 mmol.L-1 markedly inhibited the contractile response and the 45Ca2+ influx induced by DLF. These results suggest that DLF induces extracellular Ca2+ entry through voltage dependent Ca2+ channel and Ca2+ release from the intracellular Ca2+ pool which is sensitive to phenylephrine.

Animals↗
PubMed1993

Effect of Panax notoginseng saponins on increased proliferation of cultured aortic smooth muscle cells stimulated by hypercholesterolemic serum.

Panax notoginseng saponins (PNS) was extracted from a Chinese herb medicine. After preparation of cultured aortic smooth muscle cell (SMC) from primary aortic explants, the cytotoxicity of hypercholesterolemic serum (HCS) for cultured cells was determined by trypan blue exclusion test, and [3H]thymidine incorporation and cell numbers were counted at the same time. The results showed that HCS (0.5 mg cholesterol.ml-1) increased the incorporation of [3H]thymidine into cultured cells (3722 +/- 440 vs 1655 +/- 288 dpm/microgram cell proteins, P < 0.01), stimulated the proliferation of SMC [(6.5 +/- 1.5) x 10(5) vs (4.3 +/- 1.2) x 10(5) cells/plate, P < 0.01], and that high concentration HCS (final cholesterol concentration 2 mg.ml-1) was cytotoxic to the cultured cells. PNS (100 and 400 micrograms.ml-1) decreased the incorporation of [3H]thymidine into SMC in culture with or without HCS (1292 +/- 260 and 982 +/- 314 or 4111 +/- 886 and 2361 +/- 751 dpm/microgram cell protein), and inhibited the proliferation of the cultured cells [(3.3 +/- 0.7) x 10(5) and (2.9 +/- 0.7) x 10(5) or (4.7 +/- 1.4) x 10(5) and (4.1 +/- 1.2) x 10(5) cells/plate). We conclude that PNS can inhibit the proliferation of aortic SMC stimulated by HCS. These results also suggest that HCS may play an atherogenic role in the arterial wall and that PNS may prevent atherosclerosis and inhibit progression of the atherosclerotic lesions by interfering with the proliferation of arterial SMC.

Animals↗
PubMed1992

[Comparative effects of Panax notoginseng saponins, verapamil, and norepinephrine on cerebral circulation in anesthetized rats and rabbits].

In urethane-anesthetized New Zealand rabbits, mean blood pressure (MBP) and cerebrovascular resistance (CVR) fell by 27-47% and 11-17% (P < 0.05), respectively after Panax notoginseng saponins (PNS) 20-80 mg.kg-1 i.v. Verapamil (Ver) 30 micrograms.kg-1 i.v. showed similar effects, but norepinephrine (NE) 30 micrograms.kg-1 i.v. showed opposite effects. PNS and Ver reduced the MBP and CVR in sodium pentobarbital-anesthetized Wistar rats. The actions of PNS and Ver on cerebral blood flow (CBF) were related to the animal species, i.e. PNS increased CBF in rats but reduced that in rabbits, Ver increased CBF in rabbits but had no effects on that in rats. In isolated ring segments of New Zealand rabbit basilar arteries, PNS 1 and 3 mg.ml-1 non-competitively inhibited the contractions induced by KCl with the pD2' value 2.69 +/- 0.20 (-lg g.ml-1). The results indicate that PNS and Ver are vasodilators of brain blood vessel, which would be beneficial to cerebral circulation, while NE is a vasoconstrictor of brain blood vessel.

Animals↗
PubMed1991

Alpha 1-adrenoceptors mediate the responses to BHT-920 and rauwolscine in dog mesenteric artery after partial depolarization by KCl.

In normal (5 mM KCl) HEPES buffer solution, BHT-920 and rauwloscine did not produce any contractile responses in dog mesenteric artery strips. However, when the preparation was bathed in 20 mM KCl HEPES buffer solution, BHT-920 and rauwloscine evoked significant contractile responses. These effects were markedly inhibited by parazosin which caused a parallel shift to the right of the concentration-response curve to BHT-920. In 45Ca uptake experiments carried out in the 20 mM KCl HEPES buffer solution BHT-920 and rauwolscine significantly increased 45Ca influxes which were reduced by prazosin. These results suggest that postsynaptic alpha 1-adrenoceptors in dog mesenteric artery mediate the contractile responses and the 45Ca influxes induced by BHT-920 and rauwloscine after partial depolarization by 20 mM KCl.

Adrenergic alpha-Agonists↗
PubMed1991

Positive inotropic and toxic action of direct lytic factor on isolated working guinea pig hearts.

The positive inotropic and the toxic effects of direct lytic factor (DLF) on the isolated working guinea pig hearts were studied. As compared with baseline values, DLF 1-10 micrograms.ml-1 increased aortic flow up to 138% cardiac output 116%, left ventricular pressure volume work 136%, left ventricular pressure 114%, dP/dtmax 130%, Vmax 128%, and mean aortic systolic pressure 114%, but coronary flow was decreased by 16% on an average (n = 6). However, heart rate remained constant, myocardial oxygen consumption and efficiency were changed little. The cardiotonic effect of DLF was also observed by recording the isometric contractions of the isolated guinea pig papillary muscles and by determining the left ventricular pressure and dP/dtmax in anesthetized dogs. Neither spontaneously beating rate of right atrium nor the excitability of left atrium in vitro was affected by DLF. The results show that DLF is one of the cardiotonic agents without chronotropic effect and its coronary vasoconstriction effect plays an important part in heart failure.

Animals↗
PubMed1990

[Protective effects of Panax notoginseng saponins on experimental myocardial injury induced by ischemia and reperfusion in rat].

Effects of total saponins of Panax notoginseng (PNS) and purified ginsenosides Rb1 and Rg1 from PNS on myocardial injury induced by cardiac ischemia and reperfusion were studied with rat hearts in situ and in vitro. In pentobarbital-anesthetized rats, PNS pretreatment (100 and 200 mg/kg) provided significant reduction in myocardial infarct size after left descending coronary artery ligation (40 min) and reperfusion (120 min) in comparison with the control. PNS 12.5 and 25 mg/L, Rb1 10 mg/L, and Rg1 10 mg/L significantly decreased cardiac CPK release, attenuated myocardial Ca2+ accumulation, reduced malondialdehyde (MDA) production and prevented reduction of superoxide dismutase (SOD) activity in comparison with the control in perfused isolated rat hearts with global ischemia (40 min) and reperfusion (15 min). The results show that PNS, Rb1, and Rg1 prevent cardiac ischemia and the action is considered to be related to the inhibition of lipid peroxidation.

Animals↗
PubMed1989

[Effects of Panax notoginseng saponin Rb1 and Rg1 on myocardial action potential and slow inward current].

The effects of Rb1, Rg1 (purified saponin of Panax notoginseng) on contraction force, action potential and slow inward current of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques. The contraction force was decreased and the APD20 was shortened in the presence of Rb1 1 mg/ml, while the RP, APA and Vmax remained unchanged. The amplitude of Isi was decreased from a peak value of 9.8 +/- 1.6 to 7.3 +/- 3.4 microA after 20 min perfusion with Rb1 solution. This effect was reversed by increasing calcium concentration. Rg1 1 mg/ml decreased the contraction force significantly without affecting the configuration of action potential and the amplitude of slow inward current. The results indicate that Rb1 has a blocking effect on calcium channels, but Rg1 has not.

Action Potentials↗
PubMed1989

[Effects of Panax notoginseng saponins on cardiac action potentials and slow inward current].

The effects of total saponins of Panax notoginseng (PNS) on contraction force, normal and slow response action potentials and slow inward current of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques. The contraction force was decreased and the APD20, APD90 of normal AP were shortened in the presence of PNS 1 mg/ml, while the RP, APA and Vmax remained unchanged. The APA of slow AP induced with high K+ was decreased to 85% of its normal value after 20 min of perfusion with PNS solution. Isi was decreased from a peak value of 9.8 +/- 2.0 to effects of PNS on slow affecting INa. The 6.9 +/- 3.6 microA without AP and Isi were reversed by increasing calcium concentration. The results indicate that PNS has a selective blocking effect on calcium channels.

Action Potentials↗