Biomedical subjects

Chun-Su Yuan

Publications and source records attributed to Chun-Su Yuan.

At least 37 records · Page 2Linked to original sources

PubMed2005

Effects of ganoderma lucidum extract on chemotherapy-induced nausea and vomiting in a rat model.

Chemotherapy is highly cytotoxic, causing a number of severe adverse effects such as nausea and vomiting. Herbal medicines, which can often be used on a daily basis for prolonged treatment, may be clinically beneficial. Ganoderma lucidum or Lingzhi mushroom has been recognized as a remedy in treating a number of medical conditions, including balancing immunity and decreasing drug-induced side effects. It has been shown that rats react to emetic stimuli, like the chemotherapy agent cisplatin, by increased consumption of kaolin, known as pica; and this rat model has been utilized to evaluate novel anti-emetic compounds. In this study, we evaluated the effects of a G. lucidum extract (SunRecome, the most commonly used Lingzhi mushroom extract in China) in attenuating cisplatin-induced nausea and vomiting in the rat pica model. We observed that intraperitoneal cisplatin injection caused a significant increase in kaolin intake at 24, 48, 72 and 96 hours, reflecting cisplatin's nausea and vomiting action. This cisplatin-induced kaolin intake dose-dependently decreased after 1, 3 and 10 mg/kg G. lucidum extract injection (p < 0.01). In addition, there was a significant reduction of food intake after cisplatin. The cisplatin-induced food intake reduction improved significantly after G. lucidum extract administrations in a dose-related manner (p < 0.01), suggesting a supportive effect of the extract on general body condition. Future controlled clinical trials are needed to evaluate the safety and effectiveness of this herbal medication.

Animals↗

PubMed2005

Tolerability, gut effects, and pharmacokinetics of methylnaltrexone following repeated intravenous administration in humans.

Previous studies have shown that a single dose of methylnaltrexone, a unique peripheral opioid antagonist, reverses opioid-induced gut hypomotility in humans. Because repeated drug doses are likely to be needed to treat patients with opioid-induced or postsurgical bowel dysfunction, the authors have now examined the safety, pharmacological activity, and pharmacokinetics of a multiple-dose regimen of methylnaltrexone, administered as 12 consecutive intravenous doses (0.3 mg/kg every 6 hours) in 12 healthy subjects. Steady state was achieved rapidly, and after repeated dosing for 3 days, methylnaltrexone decreased oral-cecal transit time from a pretreatment baseline value of 101.3 +/- 29.4 min (mean +/- SD) to 82.5 +/- 20.7 min. Maximum observed plasma concentrations, measured 5 minutes postdose, were 538 +/- 237 and 675 +/- 180 ng/mL after doses 1 and 2, respectively. Based on 6-hour sampling periods, the plasma half-life, 2.5 +/- 0.5 and 2.9 +/- 0.9 hours following the 1st and 12th doses, respectively, was unchanged at steady state. There was essentially no accumulation of methylnaltrexone, based on the ratio of AUC values after doses 12 and 1. This study showed that repeated administration of intravenous methylnaltrexone is well tolerated in humans, with no significant adverse events or changes in opioid subjective ratings and no clinically noteworthy alterations in pharmacokinetics. The observation of a significant reduction in the gut transit time after repeated administration of methylnaltrexone to these opioid-naive volunteers suggests that endogenous opioids modulate human gut motility.

Adult↗

PubMed2004

Anti-diabetic effect of ginsenoside Re in ob/ob mice.

We evaluated the anti-diabetic effects of ginsenoside Re in adult male C57BL/6J ob/ob mice. Diabetic ob/ob mice with fasting blood glucose levels of approximately 230 mg/dl received daily intraperitoneal injections of 7, 20 and 60 mg/kg ginsenoside Re for 12 consecutive days. Dose-related effects of ginsenoside Re on fasting blood glucose levels were observed. After the 20 mg/kg treatment, fasting blood glucose levels were reduced to 188+/-9.2 and 180+/-10.8 mg/dl on Day 5 and Day 12, respectively (both P<0.01 compared to vehicle group, 229+/-9.5 and 235+/-13.4 mg/dl, respectively). The EC(70) of ginsenoside Re was calculated to be 10.3 mg/kg and was used for subsequent studies. Consistent with the reduction in blood glucose, there were significant decreases in both fed and fasting serum insulin levels in mice treated with ginsenoside Re. With 12 days of ginsenoside treatment, glucose tolerance of ob/ob mice increased significantly, and the area under the curve for glucose decreased by 17.8% (P<0.05 compared to vehicle treatment). The hypoglycemic effect of the ginsenoside persisted even at 3 days of treatment cessation (blood glucose levels: 198+/-13.1 with ginsenoside treatment vs. 253+/-20.3 mg/dl with vehicle, P<0.01). There were no significant changes in body weight or body temperature. Preliminary microarray analysis revealed differential expression of skeletal muscle genes associated with lipid metabolism and muscle function. The results suggest that ginsenoside Re may prove to be useful in treating type 2 diabetes.

Analysis of Variance↗

PubMed2004

Brief communication: American ginseng reduces warfarin's effect in healthy patients: a randomized, controlled Trial.

BACKGROUND: People using prescription medication often concurrently take herbal supplements. In a case report, the anticoagulant effect of warfarin decreased after patients consumed ginseng. OBJECTIVE: To evaluate the interactions between American ginseng and warfarin. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: General Clinical Research Center, University of Chicago, Chicago, Illinois. PARTICIPANTS: 20 healthy patients. INTERVENTION: In this 4-week study, 20 patients received warfarin for 3 days during weeks 1 and 4. Beginning in week 2, patients were assigned to receive either American ginseng or placebo. MEASUREMENTS: International normalized ratio (INR) and plasma warfarin level. RESULTS: The peak INR statistically significantly decreased after 2 weeks of ginseng administration compared with placebo (difference between ginseng and placebo, -0.19 [95% CI, -0.36 to -0.07]; P = 0.0012). The INR area under the curve (AUC), peak plasma warfarin level, and warfarin AUC were also statistically significantly reduced in the ginseng group as compared with the placebo group. Peak INR and peak plasma warfarin level were positively correlated. LIMITATIONS: The study sample consisted of young, healthy volunteers in a research setting rather than patients taking therapeutic doses of warfarin. CONCLUSIONS: American ginseng reduces warfarin's anticoagulant effect. When prescribing warfarin, physicians should ask patients about ginseng use.

Adult↗

PubMed2004

Methylnaltrexone prevents morphine-induced kaolin intake in the rat.

Opioids are frequently used analgesics, and emesis is a common opioid-induced adverse effect. Methylnaltrexone, a peripheral opioid antagonist, has the potential to block the undesired effects of opioids that are mediated by peripheral receptors while sparing the analgesic effect. We used a rat model of simulated emesis or pica to study if methylnaltrexone decreases morphine induced-kaolin consumption. We observed that after morphine administration, kaolin intake increased significantly compared to intake in the vehicle group, and the increase could be attenuated by ondansetron administration. Methylnaltrexone dose-dependently reduced kaolin ingestion induced by morphine. Morphine and methylnaltrexone did not significantly affect food intake and body weight in the experimental animals. Our data suggest that methylnaltrexone has therapeutic value in treating opioid-induced nausea and vomiting.

Animals↗

PubMed2004

Antioxidant effects of American ginseng berry extract in cardiomyocytes exposed to acute oxidant stress.

It is postulated that antioxidant properties of American ginseng root mediate its cardioprotective actions. The antioxidant capabilities of the American ginseng root have been demonstrated previously, however, the berry of the American ginseng has not yet been evaluated. In this study, we tested the American ginseng berry extract (AGBE) for its antioxidant effects in cell-free chemical systems using H(2)O(2)/FeSO(4) to generate hydroxyl radicals which were measured by a fluorescent probe, 2', 7'-dichlorofluorescin diacetate (DCFH/DA). Xanthine/xanthine oxidase was used to generate superoxide anion, which was measured by a fluorescent probe dihydroethidium (DHE). We found that AGBE decreased fluorescence significantly, suggesting that AGBE scavenges oxygen free radicals. We further tested whether AGBE (0.1-1 mg/ml) can protect cardiomyocytes from oxidative injury induced by exogenous or endogenous oxidants. Cells were exposed to either H(2)O(2) or antimycin A (a mitochondrial electron transport chain site III inhibitor that augments mitochondrial oxidant production). The resulting oxidant stress was measured using DCFH/DA and the cell death was assessed using propidium iodide staining. Pretreatment with AGBE (1 mg/ml) significantly attenuated DCF fluorescence by 49% or 85% and reduced cell death by 59% or 63% in cells exposed to H(2)O(2) or antimycin A, respectively. When the effects of extracts from berry and root of American ginseng were compared in cardiomyocytes exposed to antimycin A, we observed that AGBE conferred greater antioxidant protection at the same dose. We conclude that AGBE is a potent antioxidant that protects cardiomyocytes against oxidant-mediated injury and this protection is partly mediated by its free radical scavenging properties.

Animals↗

PubMed2004

American ginseng leaf: ginsenoside analysis and hypoglycemic activity.

Previous studies showed that both American ginseng root and American ginseng berry extracts possess hypoglycemic properties. In this study, we investigated whether American ginseng leaves also have similar capabilities. We first analyzed the chemical constituents of American ginseng leaf and determined the content of six major ginsenosides, i.e., Rb(1), Rb(2), Rc, Rd, Re, and Rg(1), by high performance liquid chromatography (HPLC). Subsequently, we evaluated the hypoglycemic effect of American ginseng leaf extract (AGLE) in diabetic ob/ob adult mice. Animals received daily intraperitoneal injections of AGLE 50, 150 mg/kg or vehicle for 12 consecutive days. Fasting blood glucose levels, intraperitoneal glucose tolerance test (IPGTT), body weight and temperature were measured. On day 5, the 150 mg/kg AGLE group had significantly lower fasting blood glucose levels compared to vehicle-treated mice (223.0+/-13.9 mg/dl versus 258.0+/-14.0 mg/dl, P<0.05), while the blood glucose levels in 50 mg/kg group did not decrease significantly. On day 12, the glucose levels in both AGLE-treated groups were reduced significantly compared to vehicle group (180.0+/-10.0 mg/dl and 220.2+/-19.3 versus 268.0+/-10.0 mg/dl, P<0.01 and <0.05, respectively). IPGTT data showed that both AGLE 150 and 50 mg/kg groups significantly increased the glucose disposal on day 12 compared to the vehicle group. In addition, body weight decreased in ob/ob mice after AGLE treatment, and these body weight changes were accompanied by significant increases in body temperature (P<0.05). Our results suggest that AGLE possesses a significant anti-hyperglycemic and thermogenic activity and may prove to be beneficial in improving the management of type 2 diabetes.

Animals↗

PubMed2004

Ephedra-containing dietary supplements in the US versus ephedra as a Chinese medicine.

Ephedra has been commonly used in traditional Chinese medicine (TCM) without significant adverse effects. Ephedra-containing dietary supplements are widely used in the United States to promote weight reduction and energy enhancement. However, there are significant safety concerns regarding the use of ephedra-containing dietary supplements, especially when such use occurs by consumers without medical supervision. This article reviews and contrasts the usage of ephedra as a dietary supplement in the US against an herbal medication in TCM. The potential adverse effects of ephedra-containing dietary supplements are also reviewed.

Adverse Drug Reaction Reporting Systems↗

PubMed2004

Synergistic effect of Scutellaria baicalensis and grape seed proanthocyanidins on scavenging reactive oxygen species in vitro.

Scutellaria baicalensis (SbE) is a commonly used Chinese herb medicine and grape seed proanthocyanidins is a popular herbal supplement in the United States. Both herbs have been shown to possess potent antioxidant effects. Using an in vitro model to produce the reactive oxygen species (ROS) generation (H2O2/FeSO4 for hydroxyl radicals, xanthine/xanthine oxidase for suproxide), we observed that Scutellaria baicalensis and grape seed proanthocyanidins acted synergistically to scavenge ROS. Our data suggest that a combination of these two herbs can potentially enhance their antioxidant efficacy, allowing lower dosages of each drug to be used. This has the advantage of avoiding possible side effects that may arise when higher doses of a single herb are used in an attempt to achieve a maximum degree of antioxidant activity.

Drug Synergism↗

PubMed2004

Alternative therapies for male and female sexual dysfunction.

Sexual dysfunction is prevalent in both men and women. Although new pharmaceutical agents have been identified for male erectile problems, sexual desire and orgasm disorders, individuals with sexual dysfunction often seek alternative therapies, including traditional Chinese medicine. This article reviews currently used alternative therapies, such as herbal medications, L-arginine, acupuncture, biofeedback and others. Potential herb-drug interactions are also presented.

Acupuncture Therapy↗

PubMed2004

Effects of antioxidant herbs on chemotherapy-induced nausea and vomiting in a rat-pica model.

Nausea and vomiting are significant adverse effects of chemotherapeutic agents like cisplatin, and cause significant patient morbidity. Cisplatin treatment results in oxidant gut injury, which is postulated to be the primary cause of nausea and vomiting. We evaluated the effects of two antioxidant herbs, Scutellaria baicalensis and American ginseng berry, on cisplatin-induced nausea and vomiting using a rat model. Rats react to emetic or nausea-producing stimuli, such as cisplatin, with altered feeding habits, manifested by increased kaolin consumption (pica). We measured pica in rats to quantify cisplatin-induced nausea. We observed that pretreatment of rats with S. baicalensis or ginseng berry extracts resulted in a significant reduction in cisplatin-induced pica. The in vitro free radical scavenging ability of the herbal extract observed in the study, further confirmed the antioxidant action of the herb. We conclude that herbal antioxidants may have a role in attenuating cisplatin-induced nausea and vomiting.

Animals↗

PubMed2004

Effects of Corydalis yanhusuo and Angelicae dahuricae on cold pressor-induced pain in humans: a controlled trial.

Pain is considered the most common complaint worldwide for which patients seek treatment. Conventional analgesic agents play an important role in modern pain therapy, but they cause several adverse effects. Therefore, newer and better analgesics continue to be investigated. In this controlled clinical trial, the authors evaluated the analgesic effects of 2 herbal medicines, Corydalis yanhusuo and Angelicae dahuricae. They used the cold-pressor test-a simple, reliable, and widely used model in humans-for induction of tonic pain. They demonstrated that after a single, oral administration of the extracts of C. yanhusuo and A. dahuricae, the pain intensity and pain bothersomeness scores significantly decreased (both P < .01). Dose-related analgesic effect was also observed. Results from this study suggest that C. yanhusuo and A. dahuricae may have a potential clinical value for treating mild to moderate pain.

Adult↗

PubMed2004

The gamma-aminobutyric acidergic effects of valerian and valerenic acid on rat brainstem neuronal activity.

UNLABELLED: Valerian is a medicinal herb that produces anxiolytic and sedative effects. It was suggested that valerian acts via gamma-aminobutyric acid (GABA)ergic mechanisms. Previous studies showed binding of valerian extract to GABA receptors, but the functional effect of the binding has not been demonstrated. In this study we evaluated the GABAergic effect of valerian extract and one of its major constituents, valerenic acid, on brainstem neuronal activity in an in vitro neonatal rat brainstem preparation. We first observed that muscimol, a GABA(A) receptor agonist, decreased the firing rate in most brainstem neurons in a concentration-related fashion; 30 micro M produced a 38.9% +/- 3.0% (mean +/- SE) inhibition compared with control values (P < 0.01; 50% inhibitory concentration [IC(50)], 2.0 +/- 0.1 microM). This effect was antagonized by bicuculline (10 microM), a GABA(A) antagonist. Then we showed that valerian extract 3 mg/mL induced a 29.6% +/- 5.1% inhibition with an IC(50) of 240 +/- 18.7 microg/mL, whereas 100 microM valerenic acid induced a 22.2% +/- 3.4% inhibition with an IC(50) of 23 +/- 2.6 microM (both P < 0.01). Bicuculline antagonized the inhibitory effects of both the valerian extract and valerenic acid. In addition, pretreatment with valerian extract or valerenic acid decreased the brainstem inhibitory effects produced by muscimol (both P < 0.05), suggesting that these compounds play an important role in the regulation of GABAergic activity. Data from this study suggest that the pharmacological effects of valerian extract and valerenic acid are mediated through modulation of GABA(A) receptor function. Thus, valerian may potentiate the sedative effects of anesthetics and other medications that act on GABA receptors, and presurgical valerian use may cause a valerian-anesthetic interaction. IMPLICATIONS: Valerian is an herb used in treating anxiety and insomnia. We observed that the valerian effects are mediated through brain gamma-aminobutyric acid (GABA) receptors in a rat brainstem preparation. Thus, valerian may potentiate the effects of anesthetics that act on GABA receptors, and presurgical valerian use may cause a valerian-anesthetic interaction.

Animals↗

PubMed2004

Nucleus accumbens receives gastric vagal inputs.

AIM: To localize and characterize the response of single accumbal neurons to electrical stimulation of the gastric vagal fibers. METHODS: Unitary responses to electrical stimulation of the ventral and dorsal gastric vagal fibers which serve the proximal stomach were recorded extracellularly in the nucleus accumbens in anesthetized cats. RESULTS: The evoked units recorded in the nucleus accumbens consisted of phasic and tonic responses, with a mean latency of (396+/-43) ms. Convergence of ventral and dorsal gastric vagal inputs onto single phasic and tonic accumbal units was observed. For tonic inhibitory responses, convergence was exhibited when stimulation applied to both the ventral and dorsal gastric vagal branches resulted in a significantly longer inhibitory period than did stimulation of a single gastric vagal branch. Comparing the gastric vagally evoked accumbal unitary responses to the neuronal responses recorded in the nucleus tractus solitarius, parabrachial nucleus and hypothalamus in our previous studies, our data showed a higher percentage of single spike responses and shorter response duration's in the nucleus accumbens than in the other nuclei. This suggests that the synaptic drive from the gastric vagal inputs to the nucleus accumbens is less powerful than in the other structures. CONCLUSION: The present study localized and characterized gastric vagally evoked responses in the nucleus accumbens, which suggest that the nucleus accumbens may process gastric signals concerned with the ingestive process.

Animals↗

PubMed2003

Methylnaltrexone antagonizes opioid-mediated enhancement of HIV infection of human blood mononuclear phagocytes.

Opioid abuse has been postulated as a cofactor in the immunopathogenesis of human immunodeficiency virus (HIV) infection and AIDS. We and others have recently demonstrated that opioid enhances HIV infection of human macrophages through modulation of beta-chemokines and the CCR5 receptor and that this effect is reversed by naltrexone, a tertiary opioid antagonist. Tertiary opioid antagonists cannot be used in opioid-dependent patients because they precipitate withdrawal or reversal of analgesia. We determined whether the quaternary opioid antagonist methylnaltrexone (MNTX), now in phase III clinical trials for opioid-induced constipation, reverses the opioid-mediated enhancement of HIV infection of macrophages at clinically relevant doses. MNTX completely abrogated morphine-induced HIV Bal strain infection of macrophages. MNTX also inhibited the R5 strain (ADA) envelope-pseudotyped HIV replication induced by morphine. Furthermore, MNTX abolished morphine-mediated up-regulation of CCR5 receptor expression. The ability of MNTX to block opioid-induced CCR5 expression and HIV replication at clinically relevant doses may have additional benefit for opioid abusers with HIV infection, or patients with AIDS pain receiving opioids.

Cells, Cultured↗

PubMed2003

Scutellaria baicalensis extract decreases cisplatin-induced pica in rats.

PURPOSE: Nausea/vomiting are significant side effects associated with the use of chemotherapy in cancer patients. Treatment of nausea/vomiting caused by cisplatin, a potent chemotherapeutic agent and one of the most emetogenic stimuli, requires a combination of different antiemetic drugs. In this study, we investigated the effects of Scutellaria baicalensis, an antioxidant herbal medicine, on cisplatin-induced nausea using a rat model. METHODS: Rats react to emetic/nausea-producing stimuli, such as cisplatin, with altered feeding habits, manifested by pica or increased consumption of kaolin (a type of clay). We measured pica in rats to quantify cisplatin-induced nausea, and to evaluate the antinausea effect of pretreatment with S. baicalensis extract (SbE) given intraperitoneally. RESULTS: Cisplatin at 3 mg/kg induced significant pica accompanied by reduced food intake, suggesting the presence of nausea. Hence, this cisplatin dose was selected for testing the antinausea activity of SbE. Cisplatin-induced pica decreased significantly when animals were pretreated with SbE at doses of 1 mg/kg and 3 mg/kg ( P<0.01). At a higher SbE dose (10 mg/kg), kaolin consumption increased, rather than further decreased, and was significantly different from that in the groups treated with low SbE doses. CONCLUSIONS: SbE pretreatment decreased cisplatin-induced kaolin intake in the rat model of simulated nausea, suggesting that SbE and its active constituent(s) may play a therapeutic role in chemotherapy-induced emesis. Absence of therapeutic effect at the highest tested SbE dose could have been a result of prooxidant activity often associated with excess antioxidant concentration.

Animals↗

PubMed2003

Anti-diabetic effects of Gymnema yunnanense extract.

In this study, we evaluated anti-hyperglycemic effect and body weight reduction activity of Gymnema yunnanense extract in obese ob/ob and diabetic db/db mice. Animals received daily intraperitoneal injections of the extract 100 mg/kg for 12 days. On Day 5, the extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to vehicle-treated mice (161+/-14.5mg/dl versus 238+/-21.5mg/dl, P<0.01). On Day 12, the extract-treated ob/ob mice had normal fasting blood glucose levels, compared with vehicle-treated mice (119+/-3.3mg/dl versus 240+/-12.9 mg/dl, P<0.01). Glucose tolerance improved significantly. This was demonstrated by overall glucose excursion calculated as area under the curve (AUC) during the 2h intraperitoneal glucose tolerance test (IPGTT), which decreased by approximately 22% (P<0.01) compared to vehicle-treated ob/ob mice. In addition, extract-treated ob/ob mice lost weight significantly from 51.7+/-1.9 g on Day 0 to 45.7+/-1.2g on Day 12 (P<0.05 compared to vehicle-treated mice). In db/db mice, after treatment with same dose of the extract, fasting blood glucose levels also decreased significantly from Day 0 of 247+/-13.9 mg/dl to Day 5 of 172+/-7.5mg/dl and to Day 12 of 190+/-2.7 mg/dl (both P<0.01 compared to vehicle-treated group from Day 0 of 239+/-12.1mg/dl to Day 5 of 230+/-8.5mg/dl and Day 12 of 247+/-18.9 mg/dl, respectively). After 12 days of extract treatment, body weight in db/db mice reduced from 61.8+/-1.4 g on Day 0 to 59.8+/-1.1g on Day 12 (P<0.05). Our results support an in vivo anti-hyperglycemic and body weight reduction activity of G. yunnanense extract that may prove to be of clinical importance in improving the management of type 2 diabetes.

Animals↗

PubMed2003

Grape seed proanthocyanidin extract attenuates oxidant injury in cardiomyocytes.

This study sought to test whether grape seed proanthocyanidin extract (GSPE) attenuates exogenous and endogenous oxidant stress induced in chick cardiomyocytes and whether this cytoprotection is mediated by PKC activation, mito K(ATP) channel opening, NO production, oxidant scavenging, or iron chelating effects. Cells were exposed to hydrogen peroxide (H(2)O(2)) (exogenous oxidant stress, 0.5mM) or antimycin A (endogenous oxidant stress, 100 micro M) for 2h following pretreatment with GSPE at various concentrations for 2h. Cells were also pretreated with GSPE or with inhibitors of PKC (chelerytherine), mito K(ATP) channel (5-hydroxydecanoate), nitric oxide synthase (nitro-L-arginine methyl ester) for 2h. Oxidant stress was measured by 2',7'-dichlorofluorescin diacetate and cell viability was assessed using propidium iodide. Free radical scavenging and iron chelating ability was tested in vitro. GSPE dose-dependently attenuated oxidant formation and significantly improved cell survival and contractile function. However, inhibitors of PKC, mito K(ATP) channel or NO synthase failed to abolish the protective action of GSPE during H(2)O(2) or antimycin A exposure. In vitro studies suggested that GSPE scavenges H(2)O(2), hydroxyl radical and superoxide, and may chelate iron. These results indicate that GSPE confers cardioprotection against exogenous H(2)O(2)- or antimycin A-induced oxidant injury. Its effect does not require PKC, mito K(ATP) channel, or NO synthase, presumably because it acts by reactive oxygen species scavenging and iron chelating directly.

Animals↗