A Microelectrophysiologic Basis For The Fibrillation Retardant Effects Of Sulfinpyrazone And Salicylate

1981 ◽  
Author(s):  
D H S Iansmith ◽  
C B Nash ◽  
J P Bandura
Keyword(s):  
Action Potentials ◽  
Current Strength ◽  
Dependent Manner ◽  
Arterial Ligation ◽  
T Wave ◽  
Before And After ◽  
Fibrillation Thresholds ◽  
Stimulus Source ◽  
Dose Dependent ◽  
Normal Tyrode Solution

The antagonism of platelet function has been suggested as a mode of action for sudden death prophylaxis by sulfinpyrazone (S) and salicylates (A). To evaluate an antiarrhythmic means for such action, 5.0 to 20.0 mg/Kg A or S was administered i.v. to open-chest, intermittently cardiac paced canines in which arterial pressure and EKG were monitored. Fibrillation thresholds (FT) were measured before and after coronary arterial ligation and drug administration, by extrastimuli of increasing current strength during the vulnerable period of the T wave. Acutely both A and S increased FT 2 to 3 times that of post-infarcted values. To elucidate the mechanism for this response Purkinje fibers were isolated from the left ventricles of adult canines. These were pinned to the paraffin floor of a lucite isolation well, affixed with stimulating and surface recording electrodes, and partitioned with a plastic collar coated with vegetable fat to provide a fluid seal. Separate inflow and outflow ports allowed for individualized microenvironments for each chamber. After 60 min of tissue equilibration with well oxygenated, 36°C normal Tyrode Solution (TS), the fluid of the chamber distal to the stimulus source was altered to include 2-35 mg% A or 2-50 ugm/ml S, with or without CO2 substitution for O2 (pH 6.4) or HC1 (pH 6.4). Action potentials (AP) from each chamber were monitored during 60 min of altered TS and then 60 min of normal TS reperfusion. In a dose-dependent manner A depressed AP parameters to cause automaticity and inactivity, while S was without effect. Whereas S was able to prolong tissue survival and support electrical activity in a situation of local acidosis (if absolute hypoxia were not superimposed), A was not. Such information suggests that although both A and S are arrhythmia retardant in the postinfarction period, their modes of action may differ. Both might act as “membrane stabilizers”; however, it appears that electrogenic aberration is necessary before S manifests an effect.

Abstract 272: Sex Differences in β-Adrenergic Responsiveness of Excitation-Contraction Coupling in Isolated Rabbit Hearts

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Gregory Hoeker ◽  
Ashleigh Hood ◽  
Rodolphe Katra ◽  
Steven Poelzing ◽  
Steven Pogwizd
Keyword(s):  
Sex Differences ◽  
Action Potentials ◽  
Adrenergic Receptor ◽  
Calcium Release ◽  
Dependent Manner ◽  
Ectopic Activity ◽  
Dose Threshold ◽  
Ectopic Beats ◽  
Cardioprotective Effects ◽  
Dose Dependent

Introduction: Sex differences in β-adrenergic receptor (β-AR) responsiveness are associated with female cardioprotection. We hypothesize that female (F) rabbits have reduced responsiveness to β-AR stimulation vs males (M), and that the degree and type of sex differences vary with the β-AR subtypes that are activated. Methods: Ventricular action potentials (AP) and intracellular calcium transients (CaT) were optically mapped from the epicardial surface of rabbit hearts during 3 Hz pacing. Spontaneous calcium release (SCR) and ectopic activity were elicited at 1, 3, and 5.5 Hz. β-responsiveness was assessed with the nonselective β-agonist isoproterenol (Iso, 1-316 nM), or β2-AR selective agonist zinterol (Zin, 10 nM). Results: At baseline, the time constant of CaT decay (τ) was faster in F than M (54.0±1.7 vs 62.1±3.0 ms; n=14, 14; p < 0.05), with no sex difference in CaT duration (CaD80). AP duration (APD90) was shorter in F than M (202.5±5.0 vs 218.2±5.7 ms; p < 0.05). Iso decreased τ, CaD80, and APD90 in a dose-dependent manner in both sexes (n = 5, 5 for F, M). Iso decreased τ to a lesser extent in F than M for 1 and 32-316 nM Iso (F = 11-32 ms, M = 23-48 ms; p < 0.05). The Iso-induced decrease in CaD80 was not significantly different in F than M at any dose. The Iso-induced decrease in APD90 was significantly less in F than M only at 316 nM Iso (75.5±8.7 ms vs 103.9±6.2 ms, p < 0.05). In contrast, there were no sex differences in the response to Zin for τ, CaD80, or APD90 (n = 6, 6 for F, M). Zin decreased τ by 7.2±2.0 ms in F vs 12.7±3.7 ms in M; CaD80 by 18.0±5.3% in F vs 21.1±8.0 ms in M; and APD90 by 24.9±8.5 ms in F vs 21.9±8.9 ms in M. SCR was observed in 50% (6/12) of hearts treated with Zin, whereas Iso elicited SCR in all hearts (10/10) with a dose threshold of 32 nM. No ectopic beats were observed with Zin (0/36 trials in 12 hearts). With Iso, ectopic activity was less frequent in F hearts (16%, 12/75 trials in 5 hearts) than in M hearts (41%, 26/68 trials in 5 hearts, p < 0.05). Conclusions: These results suggest that sex differences in AP and CaT depend on the dose of the agonist used and the β-AR subtypes that are activated. Elucidating nuances of sex differences in β-AR subtype physiology will provide a better understanding of the mechanisms of reduced β-responsiveness in F and its cardioprotective effects.

Calcium dependence of the thrombin-induced increase in endothelial albumin permeability

1989 ◽  
Vol 66 (3) ◽  
pp. 1471-1476 ◽  
Author(s):  
H. Lum ◽  
P. J. Del Vecchio ◽  
A. S. Schneider ◽  
M. S. Goligorsky ◽  
A. B. Malik
Keyword(s):  
Endothelial Cells ◽  
Endothelial Permeability ◽  
Base Line ◽  
Dependent Manner ◽  
Extracellular Medium ◽  
Influx Rate ◽  
Before And After ◽  
Dependent Inhibition ◽  
Permeability Increase ◽  
Dose Dependent

We examined whether the increase in endothelial albumin permeability induced by alpha-thrombin is dependent on extracellular Ca2+ influx. Permeability of 125I-albumin across confluent monolayers of cultured bovine pulmonary artery endothelial cells was measured before and after the addition of 0.1 microM alpha-thrombin. In the presence of normal extracellular Ca2+ concentration ([Ca2+]o, 1000 microM), alpha-thrombin produced a 175 +/- 10% increase in 125I-albumin permeability. At lower [Ca2+]o (100, 10, 1, or less than 1 microM), alpha-thrombin caused a 140% increase in permeability (P less than 0.005). LaCl3 (1 mM), which competes for Ca2+ entry, blunted 38% of the increase in permeability. Preloading endothelial monolayers with quin2 to buffer cytosolic Ca2+ (Cai2+) produced a dose-dependent inhibition of the increase in 125I-albumin permeability. Preincubation with nifedipine or verapamil was ineffective in reducing the thrombin-induced permeability increase. A 60 mM K+ isosmotic solution did not alter base-line endothelial permeability. alpha-Thrombin increased [Ca2+]i in a dose-dependent manner and the 45Ca2+ influx rate. Extracellular medium containing 60 mM K+ did not increase 45Ca2+ influx, and nifedipine did not block the rise in 45Ca2+ influx caused by alpha-thrombin. Ca2+ flux into endothelial cells induced by alpha-thrombin does not occur through voltage-sensitive channels but may involve receptor-operated channels. In conclusion, the increase in endothelial albumin permeability caused by alpha-thrombin is dependent on Ca2+ influx and intracellular Ca2+ mobilization.

Role of Nitric Oxide towards Vasodilator Effects of Substance P and ATP in Human Forearm Vessels

1997 ◽  
Vol 92 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Masanari Shiramoto ◽  
Tsutomu Imaizumi ◽  
Yoshitaka Hirooka ◽  
Toyonari Endo ◽  
Takashi Namba ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Substance P ◽  
Sodium Nitroprusside ◽  
Forearm Blood Flow ◽  
Dependent Manner ◽  
Human Forearm ◽  
Before And After ◽  
Dose Dependent

1. It has been shown in animals that substance P as well as acetylcholine releases endothelium-derived nitric oxide and evokes vasodilatation and that ATP-induced vasodilatation is partially mediated by nitric oxide. The aim of this study was to examine whether vasodilator effects of substance P and ATP are mediated by nitric oxide in humans. 2. In healthy volunteers (n = 35), we measured forearm blood flow by a strain-gauge plethysmograph while infusing graded doses of acetylcholine, substance P, ATP or sodium nitroprusside into the brachial artery before and after infusion of NG-monomethyl-l-arginine (4 or 8 μmol/min for 5 min). In addition, we measured forearm blood flow while infusing substance P before and during infusion of l-arginine (10 mg/min, simultaneously), or before and 1 h after oral administration of indomethacin (75 mg). 3. Acetylcholine, substance P, ATP or sodium nitroprusside increased forearm blood flow in a dose-dependent manner. NG-Monomethyl-l-arginine decreased basal forearm blood flow and inhibited acetylcholine-induced vasodilatation but did not affect substance P-, ATP-, or sodium nitroprusside-induced vasodilatation. Neither supplementation of l-arginine nor pretreatment with indomethacin affected substance P-induced vasodilatation. 4. Our results suggest that, in the human forearm vessels, substance P-induced vasodilatation may not be mediated by either nitric oxide or prostaglandins and that ATP-induced vasodilatation may also not be mediated by nitric oxide.

scholarly journals The Chronotropic Function of Propofol and the Underlying Mechanism in Rabbits

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Wenjie Cheng ◽  
Xiaohua Sun ◽  
Yanfang Liu ◽  
Shiqi Han ◽  
Wanlu Ren
Keyword(s):  
Heart Rate ◽  
Action Potentials ◽  
Sinus Node ◽  
Underlying Mechanism ◽  
Dependent Manner ◽  
Pacemaker Cells ◽  
Concentration Dependent Manner ◽  
Sinoatrial Nodes ◽  
Chronotropic Action ◽  
Dose Dependent

The report of bradycardia caused by propofol is increasing. In the experiment, we investigated the chronotropic function of propofol and the underlying mechanism. Rabbits of both sexes were randomly divided into 4 groups: propofol 5 mg/kg group, 10 mg/kg group, 15 mg/kg group, and sham group. Heart rate and frequency of vagal efferent discharge were recorded before the injection and 0, 0.5, 1, 2, and 10 min after the injection through intravenous mode. Then, their hearts were removed, and sinoatrial nodes were dissected. The action potentials of the sinus node pacemaker cells were recorded by the intracellular glass microelectrode technique, and the sinoatrial (SA) node was exposed to propofol 1, 3, 5, and 10 µM respectively. The action potentials were recorded after the sinoatrial nodes were exposed to each concentration of propofol for 15 min. Our results show that the heart rate significantly decreased, and the vagal efferent discharge was significantly increased at 0, 0.5, 1, and 2 min after the injection, respectively. Besides, as the dose increases, the magnitude of change shows a dose-dependent manner. Propofol exerts a negative chronotropic action on sinoatrial node pacemaker cells. The drug significantly decreased APA, VDD, RPF, and prolonged APD90 in a concentration-dependent manner. These effects may be the main mechanism of propofol-induced bradycardia in clinical study.

scholarly journals Pharmacokinetic Profile of Spectrum Reduced Nicotine Cigarettes

2019 ◽  
Vol 22 (2) ◽  
pp. 273-279 ◽  
Author(s):  
Helen M Kamens ◽  
Constanza P Silva ◽  
Russell T Nye ◽  
Carley N Miller ◽  
Nayantara Singh ◽  
...  
Keyword(s):  
Subjective Effects ◽  
Pharmacokinetic Profile ◽  
High Dose ◽  
Dependent Manner ◽  
Double Blind ◽  
Nicotine Content ◽  
Nicotine Concentration ◽  
Before And After ◽  
Double Blind Design ◽  
Dose Dependent

Abstract Introduction Spectrum research cigarettes have been developed with varying nicotine content for use in studies evaluating the effects of a regulatory policy reducing the permissible nicotine content in cigarettes. This study aimed to characterize the nicotine pharmacokinetic profile of Spectrum cigarettes. Methods Twelve daily smokers attended four sessions and had blood nicotine, exhaled carbon monoxide, and subjective effects measured before and after smoking either a single cigarette of their preferred brand or high (10.9 mg/cigarette), medium (3.2 mg/cigarette), or low (0.2 mg/cigarette) nicotine content Spectrum research cigarettes, in a double-blind design with order counterbalanced. Results The boost in blood nicotine concentration was dose-dependent, with a boost of 0.3, 3.9, and 17.3 ng/mL for low-, medium-, and high-nicotine content Spectrum cigarettes. The high dose Spectrum had a similar nicotine boost to the “preferred brand” cigarettes (19 ng/mL). Subjects took longer puffs on the low nicotine cigarettes, but smoked these cigarettes faster than other cigarette types. High nicotine Spectrum cigarettes reduced the urge to smoke more than other cigarette types. Conclusions This study shows that Spectrum research cigarettes produce blood nicotine absorption in a dose-dependent manner, and therefore, are appropriate for use in studies of nicotine reduction in cigarettes. Implications This is the first study to determine the pharmacokinetic profile of Spectrum reduced nicotine content research cigarettes following an overnight abstinence. These data could provide evidence to regulatory agencies about the effects of reduced nicotine cigarettes when considering regulations on tobacco reduction.

Abstract 16955: Effects of Evolocumab (AMG 145) as a Monotherapy or in Combination with Statins on Lipoprotein Particles and Subclasses

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Ren Xu ◽  
Matt Peach ◽  
Michael Tracy ◽  
Lisa Hamilton ◽  
Stephen Djedjos ◽  
...  
Keyword(s):  
Clinical Studies ◽  
Dependent Manner ◽  
Phase 2 ◽  
P Values ◽  
Lipoprotein Particles ◽  
Treatment Regimens ◽  
Phase 2 Study ◽  
Before And After ◽  
Phase 1B ◽  
Dose Dependent

Background: Evolocumab (AMG 145) reduces LDL-C alone or in combination with statins. We evaluated the effect of evolocumab on lipoprotein particles from subjects receiving evolocumab as monotherapy or combined with statins using biomarker samples collected from 2 clinical studies. Methods: Exploratory biomarker samples, taken before and after evolocumab treatment from a phase 1b study evaluating evolocumab combined with statins in hypercholesterolemic (HCL) subjects and from a phase 2 study evaluating evolocumab as a monotherapy in HCL subjects, were analyzed by NMR at LipoScience, Inc. Lipoprotein particle concentrations and size were determined using the LP-3 module. Results: Evolocumab alone or in combination with statins significantly reduced total, small, and large LDL-P in a dose-dependent manner. As shown in the table, evolocumab monotherapy reduced total LDL-P by 45% and 54%, small LDL-P by 36% and 35%, and large LDL-P by 68% and 84%, after 140 mg and 420 mg doses, respectively. LDL-P values were reduced slightly less than LDL-C (52% at 140 mg and 62% at 420 mg), but LDL-P reductions were similar to those seen for ApoB. IDL-P, total VLDL-P, and small VLDL-P were also reduced. Total HDL-P increased, primarily due to increases in large HDL-P. Similar results were obtained when evolocumab was given combined with statins, but with greater reductions in total, small, and large LDL-P. Notably, greater reductions in LDL-P or LDL-C were correlated with higher concentrations of total LDL-P, small LDL-P, triglycerides, smaller LDL size, and lower HDL-C at baseline. Conclusion: Evolocumab either alone or in combination with statins affected lipoprotein particles similarly. In both treatment regimens, LDL-C and total LDL-P were significantly reduced and large LDL-P were reduced, on average, to a greater extent than small LDL-P. Total LDL-P was reduced to a lesser extent than LDL-C. Additionally, reductions in VLDL-P and IDL-P were observed along with increases in HDL-P.

scholarly journals Environmental Pollutant Benzo[a]pyrene Induces Recurrent Pregnancy Loss through Promoting Apoptosis and Suppressing Migration of Extravillous Trophoblast

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yang Ye ◽  
Sushi Jiang ◽  
Chao Zhang ◽  
Yanxiang Cheng ◽  
Huan Zhong ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Pregnancy Loss ◽  
Recurrent Pregnancy Loss ◽  
Environmental Pollutant ◽  
Extravillous Trophoblast ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
Study Results ◽  
Before And After ◽  
Dose Dependent

Objects. To investigate the effects of environmental pollutant benzo(a)pyrene (BaP) and its metabolite benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) on human trophoblasts and on murine miscarriages. Methods. The implantation sites, fetus resorption, and abnormal fetuses were studied in pregnant mice treated with different doses of BaP by oral gavage from day 1 to day 10 of gestation. Additionally, apoptosis and related signaling pathway, and the migration and invasion of trophoblasts, were assessed before and after exposure of BPDE in Swan 71 trophoblast cell. Besides, the migration and invasion, and its related signaling pathway, were assessed in villi obtained from women. Results. We observed a concentration-dependent incidence of abnormal murine fetuses, beginning with 0.1 mg/kg BaP; with a BaP concentration of 2 mg/kg, no fetuses developed. Correspondingly, a BPDE concentration-dependent apoptosis of human trophoblasts. Beginning with 0.5 μM BPDE exposure, Bax/Caspase-3 were increased and Bcl-2 decreased. Furthermore, BPDE also inhibited, in a dose-dependent manner, the migration of villous explants from elective abortion women, consistent with the reduced migration of villous explants from women with recurrent pregnancy loss (RPL), and reduced the cell immigration in Swan 71 trophoblasts, in a dose-dependent manner measured by transwell assays. Conclusions. Our study results provide mechanistic insight to the effect of BPDE on trophoblast dysfunction through enhanced cell apoptosis and inhibited migration, providing further experimental evidence to the causative links between BaP exposure and PRL.

Peripherally administered CRF stimulates colonic motility via central CRF receptors and vagal pathways in conscious rats

2006 ◽  
Vol 290 (6) ◽  
pp. R1537-R1541 ◽  
Author(s):  
Kiyoshi Tsukamoto ◽  
Yukiomi Nakade ◽  
Christopher Mantyh ◽  
Kirk Ludwig ◽  
Theodore N. Pappas ◽  
...  
Keyword(s):  
Area Postrema ◽  
Colonic Motility ◽  
Proximal Colon ◽  
Dependent Manner ◽  
Dorsal Nucleus ◽  
Before And After ◽  
Dose Dependent ◽  
The Brain ◽  
Stimulation Of

Corticotropin releasing factor (CRF) is one of the most important factors in the mechanism of stress-induced stimulation of colonic motility. However, it is controversial whether stress-induced stimulation of colonic motility is mediated via central or peripheral CRF receptors. We investigated the hypothesis that peripherally injected CRF accelerates colonic motility through the central CRF receptor, but not the peripheral CRF receptor. A strain gauge transducer was sutured on the serosal surface of the proximal colon. Colonic motility was monitored before and after the peripheral injection of CRF. An in vitro muscle strip study was also performed to investigate the peripheral effects of CRF. Subcutaneous injection of CRF (30–100 μg/kg) stimulated colonic motility in a dose-dependent manner. The stimulatory effect of peripherally administered CRF on colonic motility was abolished by truncal vagotomy, hexamethonium, atropine, and intracisternal injection of astressin (a CRF receptor antagonist). No responses to CRF (10−9 −10−7 M) of the muscle strips of the proximal colon were observed. These results suggest that the stimulatory effect of colonic motility in response to peripheral administration of CRF is mediated by the vagus nerve, nicotinic receptors, muscarinic receptors, and CRF receptors of the brain stem. It is concluded that peripherally administered CRF reaches the area postrema and activates the dorsal nucleus of vagi via central CRF receptors, resulting in stimulation of the vagal efferent and cholinergic transmission of the proximal colon.

scholarly journals Stimulation of NTS A1 adenosine receptors differentially resets baroreflex control of regional sympathetic outputs

2008 ◽  
Vol 294 (1) ◽  
pp. H172-H182 ◽  
Author(s):  
Tadeusz J. Scislo ◽  
Tomoko K. Ichinose ◽  
Donal S. O'Leary
Keyword(s):  
Adenosine Receptors ◽  
Dependent Manner ◽  
Glutamatergic Transmission ◽  
Sprague Dawley ◽  
Response Curves ◽  
Baroreflex Control ◽  
Adenosine Receptor Agonist ◽  
Before And After ◽  
Dose Dependent ◽  
Stimulation Of

Previously we showed that pressor and differential regional sympathoexcitatory responses (adrenal > renal ≥ lumbar) evoked by stimulation of A1 adenosine receptors located in the nucleus of the solitary tract (NTS) were attenuated/abolished by baroreceptor denervation or blockade of glutamatergic transmission in the NTS, suggesting A1 receptor-elicited inhibition of glutamatergic transmission in baroreflex pathways. Therefore we tested the hypothesis that stimulation of NTS A1 adenosine receptors differentially inhibits/resets baroreflex responses of preganglionic adrenal (pre-ASNA), renal (RSNA), and lumbar (LSNA) sympathetic nerve activity. In urethane-chloralose-anesthetized male Sprague-Dawley rats ( n = 65) we compared baroreflex-response curves (iv nitroprusside and phenylephrine) evoked before and after bilateral microinjections into the NTS of A1 adenosine receptor agonist ( N6-cyclopentyladenosine, CPA; 0.033–330 pmol/50 nl). CPA evoked typical dose-dependent pressor and differential sympathoexcitatory responses and similarly shifted baroreflex curves for pre-ASNA, RSNA, and LSNA toward higher mean arterial pressure (MAP) in a dose-dependent manner; the maximal shifts were 52.6 ± 2.8, 48.0 ± 3.6, and 56.8 ± 6.7 mmHg for pre-ASNA, RSNA, and LSNA, respectively. These shifts were not a result of simple baroreceptor resetting because they were two to three times greater than respective increases in baseline MAP evoked by CPA. Baroreflex curves for pre-ASNA were additionally shifted upward: the maximal increases of upper and lower plateaus were 41.8 ± 16.4% and 45.3 ± 8.7%, respectively. Maximal gain (%/mmHg) measured before vs. after CPA increased for pre-ASNA (3.0 ± 0.6 vs. 4.9 ± 1.3), decreased for RSNA (4.1 ± 0.6 vs. 2.3 ± 0.3), and remained unaltered for LSNA (2.1 ± 0.2 vs. 2.0 ± 0.1). Vehicle control did not alter the baroreflex curves. We conclude that the activation of NTS A1 adenosine receptors differentially inhibits/resets baroreflex control of regional sympathetic outputs.

scholarly journals Oral Administration of Ren-Shen-Yang-Rong-Tang ‘Ninjin’yoeito’ Protects against Hematotoxicity and Induces Immature Erythroid Progenitor Cells in 5-Fluorouracil-Induced Anemia

2009 ◽  
Vol 6 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Fumihide Takano ◽  
Yasuyuki Ohta ◽  
Tomoaki Tanaka ◽  
Kenroh Sasaki ◽  
Kyoko Kobayashi ◽  
...  
Keyword(s):  
Blood Cell ◽  
Oral Administration ◽  
Marrow Cell ◽  
Dependent Manner ◽  
Erythroid Progenitor ◽  
Erythroid Progenitor Cells ◽  
Cell Counts ◽  
Colony Forming Units ◽  
Before And After ◽  
Dose Dependent

The purpose of this study was to investigate the efficacy of four different Japanese and Chinese herbal prescriptions, Ren-Shen-Yang-Rong-Tang (Ninjin’yoeito, NYT), Chai-Hu-Gui-Zhi-Gan-Jiang-Tang (Saikokeishikankyoto, SKKT), Si-Jun-Zi-Tang (Shikunshito, SKT) and Si-Wu-Tang (Shimotsuto, SMT), which are traditionally used for anemia and fatigue, against hematotoxicity in mice treated with 5-fluorouracil (5-FU). NYT 1–100 mg kg–1day–1injected orally for 7 consecutive days before and after 5-FU injection significantly suppressed reductions in red blood cell, white blood cell and platelet counts in peripheral blood, and accelerated their recovery. Administration of SKKT also produced a slight but significant improvement in 5-FU-induced erythrocytopenia, whereas SMT and SKT could not prevent anemia. Oral injection of NYT also inhibited 5-FU-induced decreases in peripheral reticulocyte and bone marrow cell counts on day 10, and markedly hastened their recovery on day 20, in a dose-dependent manner. Erythroid progenitor colonies, such as colony forming units-erythroid and burst forming units-erythroid, formed by marrow cells from mice treated with 5-FU were significantly increased by oral administration of NYT. These findings suggest that NYT has the potential to protect against hematotoxicity, and also has hematopoietic activity, through stimulation of immature erythroid progenitor cell differentiation.

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