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Alzheimer disease (AD) is a neurodegenerative disorder clinically characterized by progressive cognitive and memory dysfunction, which is the most common form of dementia. Although the pathogenesis of neuronal injury in AD is not clear, recent evidences suggest that Na⁺-K⁺-ATPase plays an important role in AD, and may be a potent neuroprotective modulator against AD. This review aims to provide readers with an in-depth understanding of Na⁺-K⁺-ATPase in AD through these modulations of some factors that are as follows, which leads to the change of learning and memory in the process of AD. 1. The deficiency in Na⁺, K⁺-ATPase α1, α2 and α3 isoform genes induced learning and memory deficits, and α isoform was evidently changed in AD, revealing that Na⁺, K⁺-ATPase α isoform genes may play an important role in AD. 2. Some factors, such as β-amyloid, cholinergic and oxidative stress, can modulate learning and memory in AD through the mondulation of Na⁺-K⁺-ATPase activity. 3. Some substances, such as Zn, s-Ethyl cysteine, s-propyl cysteine, citicoline, rivastigmine, Vit E, memantine, tea polyphenol, curcumin, caffeine, Alpinia galanga (L.) fractions, and Bacopa monnieri could play a role in improving memory performance and exert protective effects against AD by increasing expression or activity of Na⁺, K⁺-ATPase., (© 2012 The Authors Fundamental and Clinical Pharmacology © 2012 Société Française de Pharmacologie et de Thérapeutique.)

Objective: To study complications and the management of the use of covered retrievable expandable metallic stents in the treatment of benign tracheal stenosis., Methods: Fully covered retrievable metal stents were placed in 21 patients with benign tracheal stenosis. Stent-related complications and the management were reviewed and analysed., Results: Twenty-eight fully covered retrievable metallic stents were successfully placed fluoroscopically in 21 patients. Stents were removed 4 - 12 months [mean (5.5 ± 2.2) mouths] after placement in all patients. Stent-related complications included granulation tissue (n = 18), stent migration (n = 4), stent expectoration (n = 2), halitosis (n = 8), mucous retention (n = 21) and mucus plugging (n = 1). Granulation tissue was removed with a carbon dioxide laser in 2 patients. Stents were replaced for 2 times and 3 times respectively in 2 patients after stent migration and stent expectoration. An additional stent was placed in 2 patients after stent migration. Symptom of halitosis was relieved after prolonged course of systemic antibiotics treatment in 8 patients. Symptom of mucous retention was relieved with nebulized saline and N-acetylcysteine saline inhalation. Mucous plug was expelled after severe coughing after suctioning using an aspirator in one patient. There were statistically significant differences in stricture diameter, rank of tachypnea and pulmonary function (FEV(1)) in all 21 patients before stent insertion and after stents removal. No patient has experienced recurrence during the follow-up period of 1 - 36 months [mean (23.2 ± 8.0) months]., Conclusion: Fully covered retrievable metallic stent may be a safe and effective in benign tracheal stenosis. Stent-related complications may be effectively managed.

The composition of different isoforms of Na+-K+-ATPase (NKA, Na/K pump) in ventricular myocytes is an important factor in determining the therapeutic effect and toxicity of cardiac glycosides (CGs) on heart failure. The mechanism whereby CGs cause these effects is still not completely clear. In the present study, we prepared two site-specific antibodies (SSA78 and WJS) against the H₁-H₂ domain of α₁ and α₂ isoforms of NKA in rat heart, respectively, and compared their influences on the effect of ouabain (OUA) in isolated rat ventricular myocytes. SSA78 or WJS, which can specifically bind with the α₁ or α₂ isoform, were assessed with enzyme linked immunosorbent assay (ELISA), Western blot and immunofluorescent staining methods. Preincubation of myocytes with SSA78 inhibited low OUA affinity pump current but not high OUA affinity pump current, reduced the rise in cytosolic calcium concentration ([Ca²⁺](i)), attenuated mitochondrial Ca²⁺ overload, restored mitochondrial membrane potential reduction, and delayed the decrease of the myocardial contractile force as well as the occurrence of arrhythmic contraction induced by high concentrations (1 mM) but not low concentrations (1 μM) of OUA. Similarly, preincubation of myocytes with WJS inhibited high OUA affinity pump current, reduced the increase of [Ca²⁺](i) and the contractility induced by 1 μM but not that induced by 1 mM OUA. These results indicate that the H₁-H₂ domain of the NKA α₁ isoform mediates OUA-induced cardiac toxicity in rat ventricular myocytes, and inhibitors for this binding site may be used as an adjunct to CGs treatment for cardiovascular disease., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: To observe the protective effect and mechanism of intermittent hypobaric hypoxia (IHH) on cardiomyocytes induced by hydrogen dioxide., Methods: Male guinea pigs were divided randomly into two groups (n = 10): intermittent hypoxia group (IHH), and control group (non-IHH). The IHH guinea pigs were exposed to a simulated 5,000 m high altitude and hypoxia in hypobaric chamber for 28 d, 6 h/d. The control guinea pigs were kept in the same environment as IHH except hypoxia exposure. Cardiomyocytes were enzymatically isolated from left ventricle of non-CIHH or CIHH guinea pigs. The contractile was assessed in guinea pigs by a video-based motion edge-detection system. The contents and activities of malondialdehyde(MDA), lactate hydrogenase(LDH) and antioxidant enzymes were evaluated by using biochemical methods., Results: 1. Hydrogen peroxide could induce contractile and diastole dysfunction, the latent period was longer in IHH cardiac myocytes. 2. After hydrogen peroxide(300 micromol/L, 10 min) perfusion, LDH and MDA contents in supernatant increased significantly in non-IHH and CIHH cardiomyocytes (P < 0.01), Whereas the contents of MDA and LDH in IHH cardiomyocytes were lower than those in non-IHH cardiomyocytes (P < 0.01). 3. The activities of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in the myocardium of IHH guinea pigs, after hydrogen peroxide (300 micromol/L, 10 min) perfusion, SOD and CAT activities decreased significantly in non-IHH and CIHH cardiomyocytes (P < 0.01), whereas the activities of SOD and CAT in CIHH cardiomyocytes were still higher than those in non-IHH cardiomyocytes., Conclusion: IHH had a protective effect on cardiomyocytes injury induced by hydrogen peroxide, which might relate with its antioxidation effects.

Chronic intermittent hypobaric hypoxia (CIHH) has been shown to attenuate intracellular Na(+) accumulation and Ca(2+) overload during ischemia and reperfusion (I/R), both of which are closely related to the outcome of myocardial damage. Na/K pump plays an essential role in maintaining the equilibrium of intracellular Na(+) and Ca(2+) during I/R. It has been shown that enhancement of Na/K pump activity by ischemic preconditioning may be involved in the cardiac protection. Therefore, we tested whether Na/K pump was involved in the cardioprotection by CIHH. We found that Na/K pump current in cardiac myocytes of guinea pigs exposed to CIHH increased 1.45-fold. The K(1) and f(1), which reflect the portion of α(1)-isoform of Na/K pump, dramatically decreased or increased, respectively, in CIHH myocytes. Western blot analysis revealed that CIHH increased the protein expression of the α(1)-isoform by 76%, whereas the protein expression of the α(2)-isoform was not changed significantly. Na/K pump current was significantly suppressed in simulated I/R, and CIHH preserved the Na/K pump current. CIHH significantly improved the recovery of cell length and contraction during reperfusion. Furthermore, inhibition of Na/K pump by ouabain attenuated the protective effect afforded by CIHH. Collectively, these data suggest that the increase of Na/K pump activity following CIHH is due to the upregulating α(1)-isoform of Na/K pump, which may be one of the mechanisms of CIHH against I/R-induced injury.

Objective: To investigate the tumor-associated antigen CA125 expression in the serum and cervical and vaginal secretions in women during normal reproductive period, and explore the clinical value of detecting tumor markers in the cervical and vaginal secretions., Methods: A total of 145 women in reproductive period were divided into 3 age groups (20-29 years, 30-39 years, and over 40 years), and their CA125 levels in cervical secretion, vaginal secretion and serum were detected by automatic electro-chemiluminescent immunoassay., Results: CA125 levels in the cervical secretion, vaginal secretion and serum showed no significant difference between the 3 age groups (P>0.05). In each group, CA125 levels differed significantly between the cervical secretion, vaginal secretion and serum (P<0.001). In the 145 women, the average CA125 level was 497.82 - or + 75.29 U/ml in the cervical secretion, 114.66 - or + 26.40 U/ml in vaginal secretion and 18.06 - or + 3.35 U/ml in serum, showing significant differences between them (P<0.001)., Conclusion: CA125 expression level is significantly higher in the cervical and vaginal secretions than in the serum in women in normal reproductive period, and its levels in cervical and vaginal secretions can be more sensitive and convenient for early detection of related diseases.

The solubilization thermodynamics and kinetics characteristics of hydrophobic pollutants anthracene in the humic acid micellar solutions have been investigated by using batch equilibrium test. The results showed that the solubilization rate of anthracene was significantly enhanced with increasing temperature. The solubilization process of anthracene was spontaneous, endothermic and entropy increasing with deltaG(theta) = -1.682 kJ/mol, deltaH(theta) = 11.96 kJ/mol, deltaS(theta) = 45.78 J/(K x mol) in 25 degrees C, as well as deltaG(theta) = -2.140 kJ/mol and -2.598 kJ/mol in 35 degrees and 45 degrees C, respectively. The solubilization data of anthracene well fitted Elovich kinetics model.

Background: Breast cancer is one of the most common malignancies in women and is highly resistant to chemotherapy. Due to its high tumour selectivity, 3-bromopyruvic acid (3-BrPA), a well-known inhibitor of energy metabolism has been proposed as a specific anticancer agent. The present study determined the effect of 3-BrPA on proliferation, cell cycle and apoptosis in the human breast cancer MCF-7 cell line and other antitumour mechanisms., Methods: MCF-7 cells were treated with various concentrations of 3-BrPA for 1 - 4 days, and cell growth was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. Marked morphological changes in MCF-7 cells after treatment with 3-BrPA were observed using transmission electron microscopy. The distributions of the cell cycle and apoptosis were analyzed by flow cytometry. Immunohistochemistry was used to indicate the changes in the expression of Bcl-2, c-Myc, and mutant p53., Results: 3-BrPA (25 microg/ml) significantly inhibited the proliferation of MCF-7 cells in a time-dependent manner. The MCF-7 cells exposed to 3-BrPA showed the typical morphological characteristics of apoptosis, including karyopycnosis, nuclear condensation and oversize cytoplasmic particles. In addition, flow cytometric assay also showed more apoptotic cells after 3-BrPA stimulation. The cells at the G0 and G1 phases were dramatically decreased while cells at the S and G2/M phases were increased in response to 3-BrPA treatment after 48 hours. Furthermore, 3-BrPA stimulation decreased the expressions of Bcl-2, c-Myc and mutant p53, which were strongly associated with the programmed cell death signal transduction pathway., Conclusion: 3-BrPA inhibits proliferation, induces S phase and G2/M phase arrest, and promotes apoptosis in MCF-7 cells, which processes might be mediated by the downregulation of the expressions of Bcl-2, c-Myc and mutant p53.

Aim: To determine whether different Na+/K+-ATPase signal transduction pathways have positive inotropic effects on normal ventricular myocytes (NC) and failing ventricular myocytes (FC), and are involved in an increase of [Ca2+]i induced by strophanthidin (Str)., Methods: A guinea pig model of congestive heart failure was made by constricting descending aorta. The left ventricular myocytes were enzymatically isolated. The effects of 25 micromol/L Str with different signal-transducing inhibitors on contractility and the calcium transient of NC or FC from guinea pigs were simultaneously assessed and compared with those in the 25 micromol/L Str-only group by a video-based, motion-edge detection system., Results: Str at 1, 10, and 25 micromol/L in NC and Str at 0.1, 1, 10, and 25 micromol/L) in FC elevated the calcium transient amplitude and increased the positive inotropic effects in a concentration-dependent manner, respectively. At the same concentration, the effects of Str were more potent in FC than in NC. In FC, both the mitogen-activated protein kinase (MAPK) and reactive oxygen species (ROS) signal transduction pathway of Na+/K+-ATPase were involved in the increase of the calcium transient induced by Str, but only activation of the MAPK pathway increased the calcium transient in NC. However, only the ROS pathway was involved in positive inotropic effects both in NC and FC., Conclusion: The present study suggests that Na+/K+-ATPase signaling pathways involved in the inotropic effects of Str in NC and FC are consistent, and Na+/K+-ATPase signaling pathways involved in the increase of [Ca2+]i by Str in NC and FC are different.

Effect of strophanthidin (Str) on intracellular calcium concentration ([Ca2+]i) was investigated on isolated ventricular myocytes of guinea pig. Single ventricular myocytes were obtained by enzymatic dissociation technique. Fluorescent signal of [Ca2+]i was detected with confocal microscopy after incubation of cardiomycytes in Tyrode' s solution with Fluo3-AM. The result showed that Str increased [Ca2+]i in a concentration-dependent manner. The ventricular myocytes began to round-up into a contracture state once the peak level of [Ca2+]i was achieved in the presence of Str (10 micromol L(- 1)), but remained no change in the presence of Str (1 and 100 nmol L(-1)). Tetrodotoxin (TTX), nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str (1 and 100 nmol L(-1)) , but had no obvious effects on the action of Str (10 micromol L(-1)). The elevation of [Ca2+]i caused by Str at all of the detected concentrations was partially antagonized by rynodine (10 micromol L(-1)) or the removal of Ca2+ from Tyrode's solution. In Na+, K+ -free Tyrode' s solution, the response of cardiomycytes in [Ca2+]i elevation to Str (10 micromol L(-1)) was attenuated, while remained no change to Str (1 and 100 nmol L(-1)). TTX, nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str at all of the detected concentrations in Na+, K+ -free Tyrode's solution. The study suggests that the elevation of [Ca2+]i by Str at the low (nomomolar) concentrations is partially mediated by the extracellular calcium influx through Ca2+ channel or a "slip mode conductance" of TTX sensitive Na+ channel. While the effect of Str at high (micromolar) concentrations was mainly due to the inhibition of Na+, K+ -ATPase. Directly triggering the release of intracellular Ca2+ from sarcoplasmic reticulum (SR) by Str may be also involved in the mechanism of [Ca2+]i elevation.

Objective: To analyze the effect of low frequency transcranial magnetic stimulation (LF-TMS) on changing neuropeptide-Y (NPY) expression and apoptosis of hippocampus neurons in epilepsy rats induced by pilocarpine (PLO)., Methods: Thirty male Sprague Dawley rats (240 g +/- 20 g) were randomly divided into 2 groups. I group simply celiac injected pilocarpine. II group celiac injected PLO after LF-TMS. Pathological item included HE staining, NPY immunohistochemical staining and apoptosis staining., Results: HE staining revealed neurons of hippocampus were obviously death and cell's structure was destroyed in PLO group. The PLO + LF-TMS group was less injured and destroyed. Using One-Way ANOVA, NPY immunohistochemical staining shown the positive cell number was increased at all areas of hippocampus in PLO group contrasting with the low positive cell number in the PLO + LF-TMS group. In PLO group the number of apoptosis cell at hippocampus areas was significant higher than the PLO + LF-TMS group., Conclusions: Using the PLO evoked epilepsy model, LF-TMS alleviated neurons injury at hippocampus area, so LF-TMS might playing an important role in resisting the progressing of epilepsy. The positive cell number of NPY increased at all areas of hippocampus, which indicated the close relation between NPY and epilepsy. NPY might have some function on resisting epilepsy.

Introduction: The aim of this retrospective study was to evaluate the clinical efficacy and limitations of different endovascular modalities in the treatment of very large and giant intracranial aneurysms., Methods: A group of 20 patients with very large and giant intracranial aneurysms treated by endovascular approaches were retrospectively analyzed. Of the 20 patients, 9 had been treated by parent artery occlusion, 8 by coil embolization, and 3 with an intracranial covered stent. Two recurrent aneurysms initially treated with coil embolization were retreated with an intracranial covered stent. Patients were followed for 9-83 months after the procedure., Results: Endovascular treatment was technically feasible in all 20 patients. One patient died 7 days after the procedure from rebleeding caused by incomplete aneurysmal occlusion. Immediate postprocedural angiograms showed that complete occlusion was achieved in 11 aneurysms, subtotal occlusion in 7, and incomplete occlusion in 2. The final angiographic results in the other 19 surviving patients confirmed complete occlusion of 15 aneurysms, subtotal occlusion in 3, and incomplete occlusion in 1. Clinical evaluations performed at the final follow-up visit showed an excellent outcome in 11 patients and a good outcome in 8., Conclusion: Endovascular treatment of giant intracranial aneurysms with coil embolization is often associated with a low complete occlusion rate and a high recanalization rate, and parent artery occlusion remains a practical option in selected patients. Based on our limited experience, the use of an intracranial covered stent appears to be a relatively simple and safe procedure for occluding very large and giant aneurysms while still maintaining the patency of the parent artery.

Vascular diseases like aneurysms, pseudoaneurysms and direct high-flow carotid-cavernous fistulas on the intracranial segment of the internal carotid artery are usually managed through transarterial embolization with detachable coils or balloons. Utility of covered stents has been reported with good results in the treatment of selective cases. But the current generation of covered stents for coronary use is rather stiff and difficult to navigate in tortuous vessels particularly in the intracranial vasculature. Herein, we report on the use and technical respects of balloon-expanded covered stents specially designed for intracranial vasculature in the treatment of two pseudoaneurysms secondary to the successful obliteration of direct CCFs on the intracranial segment of the internal carotid artery. This is the first report of covered stents specially developed for use in intracranial vasculature.

Introduction: We present a previously unreported complication following the treatment of a patient with two small, wide-necked, posterior communicating artery aneurysms., Methods: Endovascular embolization of one aneurysm was performed using a stent-assisted technique. Follow-up angiography 5 months later revealed that a coil had escaped the confinement of the stent and migrated distally without occluding any arterial branches or causing symptoms. This case report demonstrates that although a rare occurrence, a coil can break loose from the stent., Discussion: We discuss the potential mechanisms of this phenomenon and review the literature on stent-assisted aneurysm coiling in order to raise awareness of this event when embolizing small, wide-necked aneurysms with a stent-assisted technique.

Aim: To evaluate the effects of dipfluzine on the expressions of E-selectin, P-selectin, and ICAM-1 and the infiltration of polymorphonuclear leukocytes in brain ischemia-reperfusion rats., Methods: The model of focal cerebral ischemia was established with the Zea-Longa occluding suture. Dipfluzine (0.25, 0.5 and 1 mg x kg(-1)), flunarizine 0.5 mg x kg(-1) and solvent were injected separately into lingual vein at 30 min after ischemia. The occluding suture was slowly taken away to cause reperfusion at 1 h after ischemia. Rats were decapitated under anesthesia at 24 h after ischemia-reperfusion and brains were immediately removed to do the following procedures. Effects of dipfluzine on morphology of the brain tissue were observed through hematoxylin-eosin (HE) staining. By immunohistochemistry and flow cytometry technique and biochemical method, effects of dipfluzine on P-selectin, E-selectin, ICAM-1 and myeloperoxidase (MPO) were observed., Results: Dipfluzine could relieve pathological damages in the brain tissue after ischemia-reperfusion, and reduce the expressions of E-selectin, P-selectin and ICAM-1 and activities of MPO in dose-dependent manner., Conclusion: Dipfluzine depresses the expressions of P-selectin, E-selectin, and ICAM-1, which are correlated with their effects on the activities of MPO, suggesting that dipfluzine has anti-inflammation effect in certain extent and could protect brain tissue from ischemia-reperfusion injury.

Aim: To study the involvements of nuclear factor of activated T-cells (NFATc) and NF-kappaB in calcineurin-mediated ischemic brain damage in vivo., Methods: The rat transient forebrain ischemia conducted through 15 min ischemia followed by 8, 24, and 72 h reperfusion was induced using the four-vessel method. The rats were divided randomly into five groups; sham control group, ischemia/reperfusion (I/R) group, CsA treated groups (for 8, 24, and 72 h reperfusion). Western blotting was performed to detect changes of FasL, NFATc, I-kappaB-alpha, and phospho-I-kappaB-alpha protein expression, and gel shift assays for NFAT FasL-DNA binding activities., Results: Western blotting showed that the expressions of both FasL and NFATc protein were significantly increased in the hippocampus of rat subjected to transient forebrain ischemia in comparison with those of the sham control group, which were markedly reduced by CsA. The I-kappaB-alpha protein showed no changes in all groups, and phospho-I-kappaB-alpha protein was not observed in this study. Proximal and distal FasL promoter NFAT sites bind NFAT proteins from the hippocampal neurons subjected to transient forebrain ischemia, and DNA-binding activities increased significantly compared with those of the sham control group. CsA markedly inhibited these changes., Conclusion: NFATc may be involved in calcineurin-mediated ischemic brain damage and transcription factor NF-kappaB may not be involved.

Aim: To explore the relations between anti-apoptotic role of dipfluzine (DIP) and the death signaling transduction pathway initiated by CD95 molecules, and the transcription factor involved in the transcription regulation of CD95 molecules in the hippocampal CA1 region after transient forebrain ischemia., Methods: The rat forebrain transient ischemia model was established through 15 min ischemia followed by 3 days reperfusion by using the four-vessel method. The rats were divided randomly into five groups: sham control group, ischemia/reperfusion (I/R) group, DIP treated groups (20, 40 and 80 mg x kg(-1) body weight, ig, separately). Western blotting and RT-PCR were performed to detect the expression changes of Fas, FasL, caspase 10 p20, caspase 8, I-kappaB-alpha, and p-I-kappaB-alpha molecules in protein and mRNA levels, separately, and immunohistochemistry for molecular localization of Fas and FasL in rat hippocampus., Results: The expression of Fas, FasL, and caspase 10 p20 in protein and mRNA levels increased after I/R, which was inhibited significantly after treatment with 20 and 40 mg x kg(-1) of DIP (P < 0.01). In 80 mg x kg(-1) of DIP group, the expression of Fas and FasL protein was not significantly different from that of I/R group (P > 0.05). The expression of caspase 8 and I-kappaB-alpha showed no significant differences in all groups (P > 0.05), and no gene expression was observed for p-I-kappaB-alpha protein in the study. DIP significantly affected molecular distribution of Fas and FasL protein in CA1 subregion of hippocampus., Conclusion: DIP inhibits the death signaling transduction pathway initiated by CD95 molecules in rat hippocampal CA1 subregion, and NF-kappaB transcription factor may not be involved in the transcription regulation of CD95 molecules after transient forebrain ischemia.

Aim: To investigate the metabolic pathways of dipfluzine in rats., Methods: After an oral dose of dipfluzine (80 mg x kg(-1)) to rats, urine was collected for 12 h. The metabolites of dipfluzine in urine were chromatographed and identified by LC/DAD/MS methods., Results: In the rat urine, there were 1-(4-fluorophenyl)-4-piperazinylbutanone and its glucuronide, 4-hydroxybenzophenone and its glucuronide, 4-fluoro-gamma-hydroxybenzenebutanoic acid and its glucuronide and sulfate, diphenylmethanol and its glucuronide, dipfluzine, and benzophenone., Conclusion: In rats, dipfluzine was mainly metabolized in the pathways of N-desalkylation at 1- and 4-positions of piperazine ring. Some of metabolites were further conjugated with glucuronic acid and/or sulfuric acid.

Aim: To compare the pharmacokinetics of the enantiomers of trans-tramadol (trans-T) and its active metabolite, trans-O-demethyltramadol (M1), in male and female rats., Methods: Following a single oral dose of 10 mg/kg trans-T hydrochloride to rats, (+)-trans-T, (-)-trans-T, (+)-M1, and (-)-M1 in plasma were determined by a high performance capillary electrophoresis method., Results: The females showed higher plasma concentrations of (+)-trans-T, (-)-trans-T, and (+)-M1 than the males. The enantiomers of trans-T were absorbed and eliminated more slowly in the females than in the males. (+)-M1 was eliminated more slowly in the females than in the males. All pharmacokinetic parameters but Tmax of the two enantiomers of trans-T were significantly different in both sex rats. The (+)/(-)-enantiomeric ratios of the pharmacokinetic parameters for trans-T in the males were similar to those in the females. The values of Cmax, AUC(0-infinity) of the two enantiomers of M1 were significantly different in both sex rats. The (+)/(-)-enantiomeric ratios of Cmax, AUC(0-infinity) for M1 were lower than 1 in the males, larger than 1 in the females., Conclusions: Systemic exposure of (+)-trans-T, (-)-trans-T, and (+)-M1 was higher in female rats than in male rats. The stereoselectivity in pharmacokinetics of trans-T was similar, and that of M1 was different in male and female rats.

Aim: To investigate the stereoselectivity in absorption of trans tramadol (trans T) in rat intestine., Methods: The duodenum, jejunum and ileum were separately perfusated in situ with trans T dissolved in Krebs-Ringer buffer. Trans T enantiomers in the perfusate were analyzed with a high performance capillary electrophoresis (HPCE) method., Results: The absorbed fractions of trans T enantiomers were similar among the different segments of the rat intestine. The absorbed fraction of (+)-trans T was lower than that of (-)-trans T when the concentration of trans T was not higher than 40 mumol.L-1. As the concentration of trans T increased, the absorbed fractions of trans T enantiomers were reduced and the difference in absorbed fractions between trans T enantiomers became not significant., Conclusion: Trans T enantiomers can be absorbed in different parts of the rat intestine. The intestinal absorption of trans T was stereoselective, (-)-trans T being preferentially absorbed.

Aim: To evaluate the effects of strophanthidin (Str) on cardiac contractile function and sarcolemmal Na+, K+-ATPase activities in isolated guinea-pig hearts., Methods: Isolated guinea-pig hearts were perfused through aorta in a Langendorff mode. Heart rate (HR), left ventricular pressure (LVP), and first derivatives (+/-dp/dt(max)) of LVP were recorded by eight-channel physiological instrument. Cardiac sarcolemmal Na+, K+-ATPase activities were determined with colorimetry., Results: Str 0.1 nmol/L stimulated the Na+, K+-ATPase activities (P<0.05), but had no effect on HR, LVP, and +/-dp/dt(max). Str 1 nmol/L increased +dp/dt(max) (P<0.05) and Na+, K+-ATPase activities (P<0.01). Str 10 and 100 nmol/L significantly increased both LVP (P<0.05) and +dp/dt(max) (P<0.05 or P<0.01), and had no significant effects on Na+, K+-ATPase activities. However, Str 1-100 micromol/L at first enhanced the LVP and +dp/dtmax (P<0.01), then reduced them resulting from irregular contraction, and effects of Str on Na+, K+-ATPase activities revealed a concentration-dependent inhibition (P<0.01)., Conclusion: The positive inotropic effects and irregular contraction produced by Str at higher concentrations result from the inhibition of Na+, K+-ATPase activities, and the positive inotropic effects of Str at lower concentrations are not related to the inhibition of the Na+, K+-ATPase activities.

Aim: To investigate the stereoselectivity in biliary excretion of trans tramadol (trans T) and trans O-demethyltramadol (M1) in rats., Methods: After a single intravenous dose of trans T hydrochloride (10 mg.kg-1) or M1 (2.5 mg.kg-1) to rats, the bile was collected for 30 min, then, blood was obtained from the heart. The enantiomers of trans T, M1 and M1 conjugated with glucuronic acid (M1c) in the bile and plasma were analyzed by high performance capillary electrophoresis (HPCE)., Results: After the rats were given trans T, the bile concentrations of (+)-trans T were higher than those of (-)-trans T, and the (+)/(-)-trans T ratios were lower compared with those in the plasma. After the rats were given M1, the bile concentrations of (+)-M1 were higher than those of (-)-M1, and the bile concentrations of (+)-M1c were lower than those of (-)-M1c. The glucuronidation rate of (+)-M1 was lower than that of (-)-M1 in the bile., Conclusion: The biliary excretion of trans T and M1 was stereoselective, (+)-trans T and (-)-M1 being preferentially excreted.

The effects of low concentration of dihydroouabain (DHO) on intracellular calcium concentration ([Ca(2+)](i)) were investigated in guinea pig ventricular myocytes. [Ca(2+)](i) was detected by confocal microscopy and represented by fluorescent intensity. DHO (1 fmol/L~1 mmol/L) increased [Ca(2+)](i), especially at 10 pmol/L. Nisoldipine, egtazic acid, or tetrodotoxin partially inhibited the effect of 10 pmol/L DHO on [Ca(2+)](i). The effects of DHO remained in the absence of extracellular K(+) and Na(+). These results suggest that low concentration of DHO might increase [Ca(2+)](i) via the receptor-operated Ca(2+) channels, TTX-sensitive Na(+) channels or/and triggering of intracellular calcium release; Na(+)/K(+) pump and Na(+)/Ca(2+) exchange seem not involved in the effect of DHO.