Glucuronidation of naringenin in rats.
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Animals↗
Biomedical subjects
C F Chen
Publications and source records attributed to C F Chen.
Antioxidants attenuate chronic hypoxic pulmonary hypertension.
Because chronic hypoxia increases the production of oxygen radicals, we hypothesized that antioxidants attenuate chronic hypoxic pulmonary hypertension. In part 1, we examined the temporal progress in chronic hypoxic pulmonary hypertension in 46 Wistar rats exposed to hypoxia from 0-3 weeks. In part 2, we tested whether antioxidants attenuated chronic hypoxic pulmonary hypertension in 82 rats divided into 10 groups: control, fullerenol-1, U-83836E, dimethylthiourea-1, dimethylthiourea-2, hypoxia, hypoxia + fullerenol-1, hypoxia + U83836E, hypoxia + dimethylthiourea-1, and hypoxia + dimethylthiourea-2. Control animals breathed room air and were injected intraperitoneally with saline for 2 weeks. Fullerenol-1, U-83836E, and dimethylthiourea are antioxidants and were administered intraperitoneally for 2 weeks, except that dimethylthiourea was given either on days 3, 5, and 7 (dimethylthiourea-1), or on days 8, 10, and 12 (dimethylthiourea-2). Hypoxic animals were placed into a hypobaric chamber with a barometric pressure of 380 Torr for 2 weeks. Hypoxia + antioxidant groups were administered antioxidants during hypoxic exposure. We observed a gradual increase in pulmonary artery pressure, the weight ratio of right ventricle to left ventricle plus septum, and hematocrit during the 3 weeks of chronic hypoxia. These hypoxia-induced alterations were significantly attenuated by U-83836E and dimethylthiourea, but not by fullerenol-1. Neither the temporal alterations nor the antioxidant effects can be explained by the change in either tracheal neutral endopeptidase activity or the lung or plasma substance P level, perhaps because of the time lag in sampling. These results indicate that oxygen radicals play an important role in the development of chronic hypoxic pulmonary hypertension.
Animals↗
Catecholaminergic mechanisms-mediated hypothermia induced by magnolol in rats.
Intraperitoneal administration of magnolol (25-100 mg/kg) produced a dose-related fall in rats' colonic temperature. The magnolol-induced hypothermia was attenuated by pretreatment with intracerebroventricular 6-hydroxydopamine (200 microg/rat). The L-DOPA (200 mg/kg, i.p.) plus benserazide (50 mg/kg, i.p.)-induced hyperthermia was attenuated by magnolol. On the other hand, the alpha-methyltyrosine (100 mg/kg, i.p.)-induced hypothermia was potentiated by magnolol. Furthermore, magnolol (50 mg/kg, i.p.) decreased the dopamine and norepinephrine release in the hypothalamus, but did not change the concentrations for their metabolites (3,4-dihydroxyphenylacetic acid and homovanillic acid). The data suggest that magnolol decreases colonic temperature by reducing catecholaminergic activity in rat hypothalamus.
3,4-Dihydroxyphenylacetic Acid↗
Pharmacology and toxicology of herbal medicine: subacute toxicity of commonly used Chinese drugs.
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Animals↗
Expression vector containing an N-terminal epitope tag for Dictyostelium discoideum.
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Adenine Nucleotides↗
Acupuncture utilization in Taiwan.
BACKGROUND: The objective of this study was to examine the prevalence of acupuncture utilization in Taiwan by people over 20 years of age. METHODS: Stratified cluster sampling was used to randomly select 20 villages and neighborhoods (townships), a total of 8,280 people, from northern, central, southern and eastern Taiwan. A structured questionnaire was used to collect information during home visits. A total of 5,805 questionnaires were valid for use in the study. RESULTS: The complete rate of home visits was 70.1%; 73.2% of those interviewed recognized acupuncture as one of the common therapeutic methods used in traditional Chinese medicine, whereas only 12.4% had received acupuncture treatment. Typical interviewees who had received acupuncture treatment were generally ethnic from southern Fukien and aged from 30-39 years; 58.3% of the 716 interviewees had received acupuncture treatment from licensed practitioners, while the remainder were treated by non-licensed practitioners. CONCLUSIONS: The response rate to the questionnaire was high (70.1%). However, the percentage of people who had received acupuncture treatment was only 12.4%, while many people (73.2%) were familiar with it. Approximately 40% of those who received acupuncture treatment did so from non-licensed practitioners. This may reveal either a lack of awareness by the public or a lack of public protection of health and safety.
Acupuncture Therapy↗
Cloning of porcine neuron growth inhibitory factor (metallothionein III) cDNA and expression of the gene in Saccharomyces cerevisiae.
Growth inhibitory factor (GIF), a member of the metallothionein (MT) family, is also known as MTIII. This protein distinguishes itself from other MT isoforms by exerting an inhibitory effect on cortical neuron growth instead of metal ion buffering. In this work, we cloned MTIII genes from a porcine brain cDNA library. Two species of clones were isolated that vary with respect to one nt in the coding sequence. This discrepancy results in the translation of two MTIII primary structures having a different amino acid at residue 46. Herein, both MTIII cDNAs were constructed into an expression vector and transformed into yeast cells, respectively. The yeast carrying either MTIII gene displayed a similar metal tolerance when cultured in a medium containing metal. The resistance to metal toxicity was attributed to the expression of MTIII gene which was confirmed by RNA and protein analyses. The characteristics of the protein stability, metal binding affinity and ultraviolet absorption spectrum of the yeast produced MTIII are also compared with those of MTII. The comparison reveals that both MTs have similar physical characteristics. Moreover, circular dichroism spectrum of Cd saturated MTIII was analyzed as well. Typical Cys-Cd bands for MTII appear in the spectrum, indicating similar metal-thiol interactions for MTIII to those for other MT isoforms.
Alzheimer Disease↗
Suppression of extracellular signals and cell proliferation through EGF receptor binding by (-)-epigallocatechin gallate in human A431 epidermoid carcinoma cells.
Tea polyphenols are known to inhibit a wide variety of enzymatic activities associated with cell proliferation and tumor progression. The molecular mechanisms of antiproliferation are remained to be elucidated. In this study, we investigated the effects of the major tea polyphenol (-)-epigallocatechin gallate (EGCG) on the proliferation of human epidermoid carcinoma cell line, A431. Using a [3H]thymidine incorporation assay, EGCG could significantly inhibit the DNA synthesis of A431 cells. In vitro assay, EGCG strongly inhibited the protein tyrosine kinase (PTK) activities of EGF-R, PDGF-R, and FGF-R, and exhibited an IC50 value of 0.5-1 microgram/ml. But EGCG scarcely inhibited the protein kinase activities of pp60v-src, PKC, and PKA (IC50 > 10 micrograms/ml). In an in vivo assay, EGCG could reduce the autophosphorylation level of EGF-R by EGF. Phosphoamino acid analysis of the EGF-R revealed that EGCG inhibited the EGF-stimulated increase in phosphotyrosine level in A431 cells. In addition, we showed that EGCG blocked EGF binding to its receptor. The results of further studies suggested that the inhibition of proliferation and suppression of the EGF signaling by EGCG might mainly mediate dose-dependent blocking of ligand binding to its receptor, and subsequently through inhibition of EGF-R kinase activity.
Antineoplastic Agents↗
Identification of cellular TSG101 protein in multiple human breast cancer cell lines.
tsg101 was identified as a tumor susceptibility gene by homozygous functional inactivation of allelic loci in mouse 3T3 fibroblasts. The human homologue was mapped at chromosome 11p15.1-2 and found to have intragenic deletion in 7 of 15 breast cancer specimens. To further confirm the relevance of defects in this gene to breast cancer, antibodies specific for the putative gene product were prepared and used to identify cellular TSG101 protein. The antibodies recognized a 46-kDa protein in human retinoblastoma WERI-27 cells labeled with [35S]methionine. This protein was not detected with preimmune sera. In cell fractionation studies, the 46-kDa protein cofractionating with glutathione S-transferase was found mainly in the cytoplasm. Similarly, when cells were immunostained with anti-TSG101 antibodies, fluorescence was localized in the cytoplasm of most of the cells. A full-size 46-kDa TSG101 protein was detected in a panel of 10 breast cancer cell lines and 2 normal breast epithelial cell lines with the same antibodies. Consistently, the full-length TSG101 mRNA was also detected in these breast cells using reverse transcription-PCR. These results indicate that homozygous intragenic deletion of TSG101 is rare in breast cancer cells.
Alleles↗
Hemodynamic effects of chronic tetrandrine treatment in Sprague-Dawley rats.
Tetrandrine is a calcium channel antagonist with reported anti-hypertensive effect. The present study aimed to investigate the hemodynamic effects of chronic tetrandrine treatment on normotensive Sprague-Dawley rats. Animals were allocated into one of the two groups: tetrandrine group and vehicle group. Tetrandrine (20 mg/kg) or vehicle was administered by gavage every 12 hours for consecutive 8 days. After 8 days of tetrandrine treatment, systemic hemodynamics and organ blood flows were measured on the next morning after an overnight fast, using radioactive microsphere method. Mean arterial pressure (96 +/- 2 vs. 118 +/- 4 mmHg) and systemic vascular resistance (254 +/- 35 vs. 369 +/- 5 dyn.sec.cm5 x 10(3)/100 g body wt) were significantly decreased in the tetrandine group as compared to the vehicle group. The cardiac-index (35.2 +/- 2.7 vs. 25.5 +/- 0.8 mL/min/100 g body wt) was increased in the tetrandrine group. The portal venous pressure, portal tributary blood flow, portal territory vascular resistance, renal blood flow, renal vascular resistance, heart rate and body weight were similar between the two groups. In conclusion, long-term treatment of tetrandrine reduced mean arterial pressure and systemic vascular resistance but did not change splanchnic or renal hemodynamics in normal rats.
Alkaloids↗
Renal R2 chemoreceptor activity is attenuated after back heating in the rat.
Recent study in our laboratory has found that renal afferent nervous activity (RANA) was decreased during and after 42 degrees C back heating (BH). To investigate which renal sensory receptor is influenced during and after BH, a C-shaped glass heating pad (42 degrees C) was used on the skin of the back overlying the kidneys. A single-unit recording was used to identify four types of renal sensory receptors, the R2 chemoreceptor (CR2), arterial mechanoreceptor (MRa), ureteropelvic mechanoreceptor (MRu) and venous mechanoreceptor (MRv) in anesthetized female Wistar rats. Renal cortical microvascular blood flow (CMBF) and urinary water, potassium and sodium output were measured. It was found that CR2 activity was significantly decreased during and after BH, but three types of MRs were not altered. CMBF and urine output were significantly increased during and after BH. It is concluded that the increase in renal hemodynamics by BH may dilute some chemicals in the kidney and decrease the firing rate of R2 chemoreceptors.
Animals↗
Measurement and pharmacokinetic analysis of buspirone by means of brain microdialysis coupled to high-performance liquid chromatography with electrochemical detection.
The feasibility of an electrochemical detection system with on-line microdialysis coupled with sensitive microbore high-performance liquid chromatography for the measurement and brain pharmacokinetic analysis of buspirone was investigated. A microdialysis probe was inserted into the right striatum of male Sprague-Dawley rats, which had been administered buspirone 10 mg/kg. i.v.). Dialysates were automatically injected through an on-line injector into a cyano microbore column coupled to an electrochemical detector. Samples were eluted with a mobile phase containing 0.1 M monosodium dihydrogenphosphate acetonitrile-diethylamine (85:15:0.1, v/v/v). pH 3.0, adjusted with orthophosphoric acids at a flow-rate of 0.06 ml/min. A biphasic phenomenon with a rapid distribution phase followed by a slower elimination phase was observed from the brain buspirone concentration-time curve. The results indicate that the brain pharmacokinetics of buspirone appear to conform to a two-compartment model.
Animals↗
Gastrodin and p-hydroxybenzyl alcohol facilitate memory consolidation and retrieval, but not acquisition, on the passive avoidance task in rats.
Gastrodin (GAS) and p-hydroxybenzyl alcohol (HBA) which is an aglycone of gastrodin, are active ingredients of Gastrodia elata Blume. In this study, we attempted to investigate the effects of acute administration of GAS and HBA on learning and memory processes such as acquisition, consolidation and retrieval, on the passive avoidance task in rats; piracetam was used as a positive control. Scopolamine, impairing learning acquisition, shortened the step-through latency in the retention test in rats. GAS and HBA did not prolong the step-through latency induced by scopolamine in the passive avoidance task, but piracetam could prolong the step-through latency induced by scopolamine. Cycloheximide, impairing memory consolidation, shortened the step-through latency in the retention test in rats. GAS at 50 mg/kg, HBA at 5 mg/kg and piracetam at 100 mg/kg could prolong the step-through latency induced by cycloheximide in the passive avoidance task. Apomorphine, impairing memory retrieval, shortened the step-through latency in the retention test in rats. GAS at 5 mg/kg, HBA at 1 mg/kg and piracetam at 300 mg/kg could prolong the step-through latency induced by apomorphine in the passive avoidance task. From the above results, we concluded that the facilitating effects of HBA on learning and memory are better than those of GAS. In conclusion, GAS and HBA can improve cycloheximide- and apomorphine-induced amnesia, but not scopolamine-induced acquisition impairment in rats. Thus, GAS and HBA can facilitate memory consolidation and retrieval, but not acquisition. The facilitating effects of GAS and HBA are different from those of piracetam.
Animals↗
Spasmolytic effect of water extract of Stemonae radix on the guinea-pig tracheal smooth muscle in vitro.
The present study examined the relaxing effect of a water extract of Baibu (Stemonae radix, the root tuber of Semona sessilifolia (Miq.) Franch. et Sav.) on carbachol-, histamine- and KCl-induced contractions of the guinea-pig isolated tracheal preparations. The results showed that Baibu (1-50 mg/ml) concentration-dependently relaxed the tracheal preparations contracted by these spasmogens with an IC50 value (mg/ml) of 2.0 +/- 0.1 for carbachol, 41.2 +/- 0.8 for histamine and 18.6 +/- 0.9 for KCl. The effect of Baibu was not affected by the pretreatment with a beta-adrenoceptor antagonist propranolol (10(-6) M), indicating that Baibu's effect was not due to an activation on beta-adrenoceptors. Baibu shifted the concentration-response curve of carbachol to the right in a parallel manner without changing the maximal response, having a pA2 value of 0.16 +/- 0.07 mg/ml (equivalent to a KB = 0.70 +/- 0.11 mg/ml). This indicates a competitive antagonism at the muscarinic receptors. Receptor binding assay indicated that Baibu interacted with the muscarinic receptors (Ki = 0.51 +/- 0.12 mg/ml) and the dihydropyridine (DHP) binding site of L-type Ca2+ channels (Ki = 8.0 +/- 1.9 mg/ml), but not with the histamine H1 receptors. Therefore, the present study demonstrates that Baibu contains the principle(s) acting on the muscarinic receptors and DHP binding sites, which contribute its relaxation effect on the airway smooth muscles.
Animals↗
The interactions of paeoniflorin and veratrine on isolated rat atria.
In this study, we attempted to identify the interactions and mechanisms between veratrine and paeoniflorin on isolated rat atria. Paeoniflorin alone showed no effect on the rat atria. Veratrine increased the atrial contraction and induced arrhythmia at 1 x 10(-5) g/ml. Veratrine could directly induce contraction and elicit tetanic contraction at 1 x 10(-4) g/ml in the left atria with or without electric stimulation. Paeoniflorin (4.8 x 10(-6) to 4.8 x 10(-3) g/ml), verapamil (2.2 x 10(-6) g/ml), tetrodotoxin (TTX) (3.2 x 10(-8) g/ml) and quinidine (7.5 x 10(-6) g/ml) inhibited the increase of contraction and delayed the onset of contraction induced by veratrine (1 x 10(-5) g/ml). The inhibitory effect of paeoniflorin combined with verapamil on the contraction induced by veratrine was more potent than that of paeoniflorin or verapamil alone. However, the inhibitory effect of paeoniflorin was not potentiated by TTX or quinidine. From the above results, the contraction evoked by veratrine in the rat atria may be concluded to be caused by the stimulation of Na(+)- and Ca(2+)-ion channels. The inhibition of paeoniflorin on the contraction induced by veratrine may primarily be related to the blockade of Ca2+ channels.
Animals↗
Inhibitory effect of dehydroevodiamine and evodiamine on nitric oxide production in cultured murine macrophages.
Possible antiinflammatory effects of dehydroevodiamine (1) and evodiamine (2) were examined by assessing their effects on NO production in the murine macrophage-like cell line RAW 264.7. The results indicated that both 1 and 2 inhibited the IFN-gamma/LPS-stimulated NO production in a concentration-dependent manner. However, 1 appeared to inhibit NO production by interfering not only with the priming signal initiated by IFN-gamma but also with iNOS protein synthesis, while 2 affected the former only.
Alkaloids↗
Cytotoxic constituents from the stems of Diospyros maritima.
One novel coumaric acid ester of lupeol, dioslupecin A (1), three naphthoquinones, 8'-hydroxyisodiospyrin (2), isodiospyrin (3), and plumbagin (4), three triterpenes, lupeol, lupenone and taraxerone, and four sterols, beta-sitosterol, stigmasterol, stigmast-4-en-3-one and ergosta-4,6,8(14),22-tetraen-3-one were isolated from the n-hexane extract of the stems of Diospyros maritima Blume. The structural determination of 1 was based on 1D and 2D NMR spectra (including 1H-1H COSY, 1H-13C COSY, and HMBC). All compounds were evaluated for in vitro cytotoxicity in 4 cancer cell lines. Compound 2 showed similar cytotoxicity against hepatoma (HEPA-3B, ED50 = 1.72 micrograms/ml), nasopharynx carcinoma (KB, ED50 = 1.85 micrograms/ml), colon carcinoma (COLO-205, ED50 = 2.24 micrograms/ml) and cervical carcinoma (HELA, ED50 = 1.92 micrograms/ml). Compounds 3 and 4 exhibited strong cytotoxicity against HEPA-3B, KB, COLO-205 and HELA (ED50 = 0.25, 1.81, 0.13 and 0.27 micrograms/ml for 3; ED50 = 0.87, 3.27, 0.56 and 0.35 micrograms/ml for 4, respectively.
Antineoplastic Agents, Phytogenic↗
Studies of the cellular mechanisms underlying the vasorelaxant effects of rutaecarpine, a bioactive component extracted from an herbal drug.
We conducted studies to investigate the nature and underlying mechanisms of the vascular effects of rutaecarpine (Rut), an alkaloid isolated from the Chinese herbal drug Evodia rutaecarpa. By using largely the effects on phenylephrine (PE)-induced contraction in the isolated rat aorta as the experimental index and by comparison with several known vascular muscle relaxants such as acetylcholine (ACh), histamine, and A23187, Rut relaxed PE-precontracted aorta in concentration-(10(-7)-10(-4) M) and endothelium-dependent manners. Studies with appropriate antagonists indicated that this was coupled to nitric oxide (NO) and guanylyl cyclase. Extracellular Ca2+ removal and treatment with the intracellular Ca2+ antagonist, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), suggested that influx of extracellular Ca2+ was the major factor contributing to the action of Rut. Pertussis toxin suppressed the relaxation potency of histamine but had no effects on the actions of Rut. NaF, the G proteins activator, attenuated the actions of ACh, but only minimally affected Na-NP, A23187, and Rut. 1-[6-{[17 beta-3-methoxyestra-1,2,3(10)-trien-17-yl]amino} hexyl]-1H-pyrrole-2,5-dione (U73122), the phospholipase C inhibitor, again suppressed the actions of ACh but had few effects on A23187 and Rut. Taken together, these results suggest that these vasorelaxants had different cellular mechanisms and that neither pertussis toxin-sensitive Gi protein, other G proteins, nor phospholipase C activation was involved in the cellular response to rutaecarpine.
Acetylcholine↗