Digoxin Ameliorates Glymphatic Transport and Cognitive Impairment in a Mouse Model of Chronic Cerebral Hypoperfusion / 神经科学通报·英文版

The glymphatic system plays a pivotal role in maintaining cerebral homeostasis. Chronic cerebral hypoperfusion, arising from small vessel disease or carotid stenosis, results in cerebrometabolic disturbances ultimately manifesting in white matter injury and cognitive dysfunction. However, whether the glymphatic system serves as a potential therapeutic target for white matter injury and cognitive decline during hypoperfusion remains unknown. Here, we established a mouse model of chronic cerebral hypoperfusion via bilateral common carotid artery stenosis. We found that the hypoperfusion model was associated with significant white matter injury and initial cognitive impairment in conjunction with impaired glymphatic system function. The glymphatic dysfunction was associated with altered cerebral perfusion and loss of aquaporin 4 polarization. Treatment of digoxin rescued changes in glymphatic transport, white matter structure, and cognitive function. Suppression of glymphatic functions by treatment with the AQP4 inhibitor TGN-020 abolished this protective effect of digoxin from hypoperfusion injury. Our research yields new insight into the relationship between hemodynamics, glymphatic transport, white matter injury, and cognitive changes after chronic cerebral hypoperfusion.

Digoxin alleviates pulmonary fibrosis by regulating phosphatidylinositol-3-kinase/Akt signaling through inhibiting the activation of fibroblast: an in vivo and in vitro experiment / 中华危重病急救医学

Objective:To investigate the effect of digoxin on bleomycin-induced pulmonary fibrosis in mice, and investigate its possible mechanism through in vitro and in vivo experiments. Methods:① In vivo experiment: 60 C57/BL6J mice were randomly divided into control group, pulmonary fibrosis model group (model group), pirfenidone (300 mg/kg) group, digoxin 1.0 mg/kg and 0.2 mg/kg groups, with 12 mice in each group. The pulmonary fibrosis model of mice was reproduced by single intratracheal infusion of bleomycin (5 mg/kg). The control group was given the same amount of sterile normal saline. From the next day after modeling, each group was received corresponding drugs by intragastric administration once a day for 28 days. Control group and model group were given the same amount of normal saline. The mice were sacrificed and the lung tissue was collected to detect the lung coefficient. After hematoxylin-eosin (HE) and Masson staining, the lung tissue morphology and collagen changes were observed under light microscope. Immunohistochemistry was used to detect the positive expressions of α-smooth muscle actin (α-SMA) and extracellular matrix (ECM) collagen (COL-Ⅰ and COL-Ⅲ) in lung tissue. The protein expressions of ECM fibronectin (FN), transforming growth factor-β (TGF-β) and phosphorylation of Smad3 (p-Smad3) in lung tissue were detected by Western blotting. ② In vitro experiment: human embryonic lung fibroblast-1 (HFL-1) cells were cultured and divided into blank control group, fibroblast activation model group (model group), pirfenidone (2.5 mmol/L) group and digoxin 100 nmol/L and 50 nmol/L groups when cell density reached 70%-90%. After 3-hour treatment with corresponding drugs, except blank control group, the other groups were treated with TGF-β for 48 hours to establish fibroblast activation model. The expressions of α-SMA, FN and p-Smad3 proteins and the phosphorylations of phosphatidylinositol-3-kinase (PI3K)/Akt pathway proteins PI3K and Akt (p-PI3K, p-Akt) were detected by Western blotting. Results:① In vivo, compared with the control group, the alveolar structure of mice in the model group was significantly damaged, a large number of inflammatory cells infiltrated, collagen deposition in the lung interstitium was increased, the deposition of ECM in the lung tissue was also increased, and the expressions of α-SMA, FN, TGF-β and p-Smad3 protein were increased, indicating that the model of bleomycin-induced pulmonary fibrosis in mice was successfully prepared. Compared with the model group, digoxin significantly inhibited airway inflammation and collagen fiber deposition, reduced ECM deposition, and decreased the protein expressions of α-SMA, FN, TGF-β and p-Smad3, while the effect was better than that of the pirfenidone group, and the digoxin 1.0 mg/kg group had a better effect except FN [α-SMA ( A value): 5.37±1.10 vs. 9.51±1.66, TGF-β protein (TGF-β/GAPDH): 0.09±0.04 vs. 0.33±0.23, p-Smad3 protein (p-Smad3/GAPDH): 0.05±0.01 vs. 0.20±0.07, all P < 0.01]. ② In vitro, compared with the blank control group, the expressions of FN, α-SMA, p-Smad3 and PI3K/Akt signaling proteins in the model group were increased, indicating that the fibroblast activation model induced by TGF-β was successfully reproduced. Compared with the model group, digoxin significantly inhibited fibroblast activation, and decreased the expressions of FN, α-SMA, p-Smad3, and PI3K/Akt pathway proteins, moreover, the effect was better than that of the pirfenidone group, and decreased FN, SMA and p-Akt protein expressions were more obvious in digoxin 100 nmol/L group [FN protein (FN/GAPDH): 0.21±0.15 vs. 0.88±0.22, α-SMA protein (α-SMA/GAPDH): 0.20±0.01 vs. 0.50±0.08, p-Akt protein (p-Akt/GAPDH): 0.30±0.01 vs. 0.65±0.10, all P < 0.01]. Conclusion:Digoxin could suppress the pulmonary fibrosis in mice induced by bleomycin, which might be associated with the regulation of fibroblast activation via suppressing PI3K/Akt signaling pathway in a dose-dependent manner.

Bidirectional Ventricular Tachycardia Due to Digitalis Intoxication

Bidirectional ventricular tachycardia (BDVT) is defined by beat-to-beat alternation of the QRS axis on the electrocardiogram. Its diagnosis is uncommon, and the most characteristic etiology is digitalis intoxication (DI). We report the case of a patient with heart failure of valve origin admitted for sepsis that progressed to BDVT and death, associated with DI.

The impact of digoxin on the long-term outcomes in patients with coronary artery disease and atrial fibrillation / 中华内科杂志

Objective:To investigate the long-term safety of digoxin in patients with coronary artery disease (CAD) and atrial fibrillation (AF).Methods:This was a prospective study, in which 25 512 AF patients were enrolled from China Atrial Fibrillation Registry Study. After exclusion of patients receiving ablation therapy at the enrollment, 1 810 CAD patients [age: (71.5±9.3)years] with AF were included. The subjects were grouped into the digoxin group and non-digoxin group, and were followed up for a period of 80 months. Long-term outcomes were compared between the groups and an adjusted Cox regression analysis was applied to evaluate the risk of digoxin on the long-term outcomes. The primary endpoint was all-cause mortality.Results:The patients were followed up for a median period of 3.05 years. After multivariable adjustment, the Cox regression analysis showed that digoxin significantly increased the risk of all-cause mortality ( HR=1.28, 95% CI 1.01-1.61, P=0.038), cardiovascular mortality ( HR=1.48,95% CI 1.10-2.00, P=0.010), cardiovascular hospitalization ( HR=1.67,95% CI 1.35-2.07, P=0.008) and the composite endpoints ( HR=2.02,95% CI 1.71-2.38, P<0.001). In the subgroup of patients with heart failure (HF), digoxin was not associated with the risk of all-cause mortality, but was still associated with the increased risk of cardiovascular mortality ( HR=1.44,95% CI 1.05-1.98, P=0.025), cardiovascular hospitalization ( HR=1.44,95% CI 1.09-1.90, P=0.010) and the composite endpoints ( HR=1.37, 95% CI 1.01-1.70, P=0.004). However, in the subgroup of patients without HF, digoxin was only associated with all-cause mortality ( HR=2.56,95% CI 1.44-4.54, P=0.001). Conclusion:Digoxin significantly increased the risk of all-cause mortality in CAD patients with AF, especially in patients without HF.

Determination of digoxin in human plasma by LC-MS/MS and its application in pediatric patients / 中国药科大学学报

@#The aim of the study was to develop a simple, rapid and accurate LC-MS/MS method for the determination of digoxin.Digoxin-d3 was taken as the internal standard (IS), and sample preparation was achieved by liquid-liquid extraction.Chromatographic separation was performed on a Kinetex C18 column (2.1 mm × 50 mm, 2.6 μm; Phenomenex) using an isocratic elution with merely 2 min for each sample.The mobile phase consisted of water and acetonitrile solutions, both containing 1 mmol/L ammonium acetate and 1 mmol/L formic acid (55∶45).The detection was conducted on a TripleQuadTM 4500MD mass spectrometer coupled with electrospray ionization interface under positive-ion multiple reaction monitoring mode.The transitions were m/z 798.5 → 651.3 and m/z 801.6 → 654.4 for digoxin and digoxin-d3, respectively.Results showed that the method was linear over the range of 0.100-20.0 ng/mL.The selectivity, accuracy and precision, recovery and stability of the method were all within the acceptable limits with no matrix effect.This method was successfully applied to a girl treated with digoxin with substantial improvement of therapeutic effect and elimination of toxic reaction, so it can provide valuable fuidance and reference for individualized medication in clinical practice.

Participation of Clinical Pharmacists in the Management of Drug Therapy for Fetal Tachycardia Treated by Oral Administration of Digoxin through Mother / 中国药房

OBJECTIVE：To investigate the ro le of clinical pharmacists in the therapy of fetal tachycardia by oral administration of digoxin through mother. METHODS ：The clinical pharmacists participated in the whole process of drug therapy for a pregnant woman with fetal tachycardia. According to 31+6 weeks of gestation ，the fetal heart rate of 230 beats/min at admission，clinical pharmacists provided the suggestion for the doctor about the safety and blood concentration determination of digoxin in the treatment of fetal tachycardia by mother. The patient ’s blood potassium value was lower than the normal range ，and it was suggested that potassium should be supplemented before digoxin was used ，and the initial dose of digoxin was 0.5 mg per 12 h. On the 7th day in the hospital ，the dosage of digoxin should be adjusted to maintaining dose （0.25 mg per 12 h）；on the 11th day in the hospital ，the patient ’s blood sodium value was low ，and the clinical pharmacists gave diet guidance. At the same time ， the clinical pharmacists explained the adverse reactions of digoxin to the doctors ，nurses and patients ，and closely observed and educated the patients. RESULTS ：Doctors adopted the suggestions of the clinical pharmacists. The fetal heart rate decreased to 180 beats/min from hospital after 13 days of treatment. The maternal digoxin concentration remained stable. No adverse drug reactions occurred in the mother and infant. CONCLUSIONS ：Maternal and child safety should be taken into account in the medication of pregnant patients. The clinical pharmacists assisting doctors to formulate medication strategying ，and carrying out pharmaceutical care for patients ，can ensure the effectiveness and safety of medication for fetal tachycardia.

A myriad of electrocardiographic findings associated with digoxin use

Digoxin is a commonly prescribed drug in the management of heart failure and atrial fibrillation. Despite its widespread use, most clinicians have little experience with recognising clinical signs and symptoms that might suggest a potentially lethal drug toxicity. We herein describe two cases with specific reference to the electrocardiographic changes induced by digoxin and discuss the predisposing factors for toxicity, recognition of possible toxicity and treatment approaches.

Association between duration of digoxin use and adverse outcomes among Chinese patients with atrial fibrillation / 中华心血管病杂志

Objective: We aimed to explore the impact of digoxin use on outcomes in Chinese patients with atrial fibrillation (AF). Methods: We used the dataset from the Chinese Atrial Fibrillation Registry, a prospective, multicenter, hospital-based registry study. According to the inclusion and exclusion criteria, 10 472 eligible patients enrolled from August 2011 to December 2016 were included in this ancillary study. The patients were classified into three groups according to the status of digoxin use at study enrollment, patients already receiving digoxin before registry were represented as continuous group, patients initiated on digoxin for the first time were represented as newly group, and patients without digoxin prescription at enrollment were represented as control group. Patients were followed by telephone or outpatient service every 6 months. Kaplan-Meier survival analysis and Cox proportional hazards regression models were used to investigate the association of digoxin use with adverse outcomes (all-cause death, cardiovascular death and cardiovascular hospitalization). Results: In the overall study population, men accounted for 42.8%, and the average age was (66.9±11.8) years. There were 777（7.42%）patients in continuous group, 375 (3.58%) patients in newly group, and 9 320 (89.00%) patients in control group. Compared with the control group, the patients in the newly group and the continuous group were older, had faster heart rate, lower estimated glomerular filtration rate, higher proportion of persistent atrial fibrillation, heart failure, renal insufficiency, diabetes mellitus, ischemic stroke, coronary heart disease, vascular disease and bleeding history. At the same time, the patients in the newly group and the continuous group were treated more often with anticoagulants, antiplatelet drugs, ACE inhibitors or angiotensin receptor blockers, beta-receptor blockers while the proportion of antiarrhythmic drugs was lower as compared to control group (P<0.05). During a median follow-up of 36 months (interquartile range: 18-48 month), risk of all-cause mortality was significantly higher in newly group compared to control group (7.3% vs. 4.7%, P<0.05), the rates of all-cause mortality, cardiovascular death and cardiovascular hospitalization were all higher in continuous group than in control group (8.0% vs. 4.7%; 4.7% vs. 3.0%; 16.7% vs. 11.8%; P all<0.05). After adjustment for age, male, body mass index, blood pressure, heart rate, renal function, AF type, history of stroke, heart failure, diabetes, coronary artery disease and other drugs treatment, the association between newly group and adverse outcomes was not significant, however, digoxin use was associated with increased all-cause mortality (HR 1.26; 95%CI 1.04-1.56; P=0.019), cardiovascular death (HR 1.38; 95%CI 1.08-1.77, P =0.01), and cardiovascular hospitalization (HR 1.10; 95%CI 1.06-1.52, P=0.02) in continuous group. Conclusion: Continuous digoxin use is associated with a significant increase in adverse outcomes among Chinese patients with atrial fibrillation.

Effects and mechanism of digoxin on atrium electrical remodeling and susceptibility of atrial fibrillation in aged rabbits / 中华心血管病杂志

Objective@#To investigate the effects and mechanism of digoxin on atrium electrical remodeling and susceptibility of atrial fibrillation (AF) in aged rabbits.@*Methods@#Twenty aged male New Zealand rabbits were divided into aged group and aged plus digoxin group (n=10 each). Electrical parameters including heart rate (HR), RR and QT interval, ST segment and P wave dispersion from normal Ⅱ electrocardiogram, and the maximum upstroke velocity (Maxdv/dt), plateau potential (plateau P), action potential duration of 10%, 20% and 90% (APD10, APD20, APD90) from recording of monophasic action potential (MAP), as well as atrial effective refractory period (AERP200) and dispersion (dERP200) with 200 ms of basic cycle length (BCL), and frequency self adaptation of AERP with 300 ms and 150 ms of BCLs (fERP) were recorded and compared between the 2 groups. BCLs and inducibility of AF post programmed electrical stimulation and Burst-pacing in left atrium tissue of rabbits in vivo were also analyzed. The L-type calcium current (ICa-L) in 2 groups were recorded via whole-cell patch clamp technique, and the fluorescence intensity of intracellular free Ca2+ was detected with Flup-3/AM loading by the laser scanning confocal microscope in enzymatically dissociated single rabbit atrial myocytes.@*Results@#Compared with aged group, the heart rate was faster, RR and QT interval were obvious shorter, ST segment was raised and P wave dispersion was significantly increased in aged plus digoxin group (all P<0.05). Moreover, compared with aged group, the Maxdv/dt and plateau P were obviously increased, APD10 and APD20 were significantly prolongated, and APD90 was significantly shorter in aged plus digoxin group (all P<0.01). Otherwise, the fERP was markedly increased (0.81±0.15 vs. 0.67±0.05), and the induced rate of AF was obviously higher in aged plus digoxin group than in aged group (6/8 vs. 4/9) (all P<0.01). With voltage clamp model, digoxin significantly increased ICa-L of atrial myocytes of aged rabbits, When command potential was 10 mV, the current densities of ICa-L were significantly higher in digoxin group than that in aged group ((15.45±2.38) pA/pF vs. (7.03±1.69) pA/pF, P<0.01). Otherwise, the I-V curve of ICa-L was downward shifted of all I-V curves in digoxin perfused aged atrial cells of rabbits. Moreover, the fluorescence intensities of intracellular free Ca2+ was significantly higher in aged plus digoxin group than in aged group ((1 748±173) μmol/L vs. (478.13±87.63) μmol/L, P<0.01).@*Conclusion@#Digoxin could aggravate the atrial electrical remodeling in atrium of aged rabbits, facilitate susceptibility of atrial fibrillation in aged rabbit, increased current density of ICa-L and concentration of intracellular free Ca2+, followed Ca2+ overload and oscillations might be part of the underlying mechanisms.

Dexmedetomidine hydrochloride up-regulates expression of hypoxia inducible factor-1α to alleviate renal ischemiareperfusion injury in diabetic rats / 南方医科大学学报

OBJECTIVE@#To verify whether dexmedetomidine hydrochloride (Dex) alleviates renal ischemia-reperfusion (IR) injury in diabetic rats by increasing the expression of hypoxia inducible factor-1 (HIF-1).@*METHODS@#A rat model of type 2 diabetes mellitus was established by high-fat diet and streptozotocin injection. The rats were subjected to daily intragastric administration of 0.05 mg/kg digoxin for 7 consecutive days and intraperitoneal injection of Dex 2 h before renal IR injury induced by ligation of the bilateral renal arteries for 60 min followed by reperfusion for 120 min. After reperfusion, blood samples were taken for detection of serum creatinine (Scr) and urea nitrogen (BUN) levels. Western blotting was used to detect the expression of HIF-1, cleaved caspase-3, Bcl-2, and Bax in the renal tissues; the expression of the HIF-1, p-eNOS, and eNOS were detected using ELISA. The percentage of apoptotic glomerular cells was assessed using TUNEL assay.@*RESULTS@#The levels of Scr, BUN, HIF-1, p-eNOS, and eNOS and the percentage of apoptotic cells in both normal and diabetic rats increased significantly after renal IR injury ( < 0.05). The expressions of Scr, BUN, p-eNOS, and eNOS decreased while HIF-1 expression increased significantly in Dex-treated rats with renal IR injury ( < 0.05). Compared with the non-diabetic rats, the diabetic rats showed more obvious increase in the expressions of Scr, BUN, p-eNOS, and eNOS following renal IR injury. In the diabetic rats with renal IR injury, Dex treatment prior to the injury significantly lowered the expressions of Scr, BUN, p-eNOS, eNOS, cleaved caspase-3, and Bax, decreased the percentage of apoptotic cells, and increased the levels of HIF-1a and Bcl-2 ( < 0.05). Digoxin treatment significantly antagonized the effects of Dex in the diabetic rats with renal IR injury by increasing the expressions of cleaved caspase-3 and Bax, promoting glomerular cell apoptosis, and decreasing renal expressions of HIF-1 and Bcl-2 ( < 0.05).@*CONCLUSIONS@#Dex alleviates renal IR injury in diabetic rats probably by inhibiting renal expression of HIF-1 and glomerular cell apoptosis.

A curious case of raised gradient across mitral bioprosthetic valve

High Doppler valve gradient is generally suggestive of valve thrombosis. However, it should be corroborated with the finding of restricted leaflet movement to confirm the diagnosis. In the present case, abnormally high gradient was not associated with limited leaflet movements or any valve thrombus.

Concurrent renal dysfunction with ischemic heart disease is an important determinant for cardiac and cerebrovascular mortality in patients on chronic digoxin therapy for atrial fibrillation

BACKGROUND: Major adverse cardiac and cerebrovascular events (MACCEs) are main concerns in patients with atrial fibrillation (AF); however, factors affecting MACCEs remain inconclusive in AF patients chronically treated with digoxin. We investigated the major clinical determinants for fatal MACCEs in AF patients treated with digoxin over a 10-year follow-up period. METHODS: We analyzed a retrospective cohort of 1,480 AF patients at Eulji University Hospital, Daejeon, South Korea from March 2004 to August 2015. Among this population, 402 consecutive patients receiving chronic digoxin therapy were selected for the study. Data for electrocardiography, medication history, laboratory values including the serum digoxin concentration (SDC) and fatal MACCEs were collected. All data were divided and compared between groups based on the occurrence of MACCEs. RESULTS: The overall incidence of fatal MACCEs among the 402 digoxin-treated AF patients (age, 68 ± 11 years; male, 40.3%) was 12.1%. These fatalities resulted from heart failure (46.1%), fatal stroke (26.9%), fatal myocardial infarction (15.3%) and sudden cardiac death (5.7%). A higher prevalence of diabetes, pre-existing ischemic heart disease (IHD), lower estimated glomerular filtration rate (eGFR), higher SDC, and junctional bradycardia were more frequently observed in patients with MACCEs compared to those without MACCEs. Multivariable analysis showed that an eGFR of ≤ 60 mL/min/1.73 m2 and pre-existing IHD had a hazard ratio of 3.35 and a confidence interval of 1.64–6.87 (P < 0.001) for fatal MACCEs. CONCLUSION: Chronic kidney disease stage III–V with pre-existing IHD is significantly associated with increased cardiac and cerebrovascular mortality in AF patients with chronic digoxin use.

Effect of six bioactive lignans of Wuzhi tablet (Schisandra sphenanthera extract) on P-glycoprotein and its herb-drug interaction with digoxin / 药学学报

This study was aimed to investigate the effects of six Schisandra lignans of Wuzhi tablet (WZ, a preparation of ethanol extract of Schisandra sphenanthera) on the pharmacokinetic process of digoxin (DG, a classical P-gp substrate) after intravenous and oral administration in rats. The effect of Schisandra lignans on the transportion of DG in Caco-2 cells was further elucidated. Our data showed that the plasma concentrations of DG were increased to different extent following co-administration of schisandrin A, schisandrin B, schisandrol B and schisantherin A, respectively. Schisandrol B showed the most potent effect among the six lignans. However, schisandrin C and schisandrol A showed little effect on pharmacokinetic of DG. Schisandrol B led to 99.0% (P < 0.05) and 109.2% (P < 0.05) increase in the AUC after orally or intravenously administered of DG, suggesting that co-administration of schisandrol B induced a more potent effect on increasing hepatic bioavailability of DG than that of intestinal. Furthermore, in vitro transport experiment showed that schisandrin A, schisandrin B, schisandrol B and schisantherin A inhibited P-gp-mediated efflux of DG, suggested that these lignans inhibited the P-gp-mediated efflux of DG. In conclusion, the exposure of DG in rats was increased when co-administered with Schisandra lignans, and schisandrol B showed the strongest effect. The dramatic increase in oral bioavailability of digoxin in the presence of schisandrol B may be due to the inhibition of hepatic/renal P-gp activity.

Antiarrhythmic drug usage and prostate cancer: A population-based cohort study / 亚洲男科学杂志(英文版)

Even though the relationship between antiarrhythmic drug usage and subsequent prostate cancer (PCa) risk has recently been highlighted, relevant findings in the previous literature are still inconsistent. In addition, very few studies have attempted to investigate the association between sodium channel blockers or potassium channel blockers for arrhythmia and the subsequent PCa risk. Therefore, this cohort study aimed to find the relationship between antiarrhythmic drug usage and the subsequent PCa risk using a population-based dataset. The data used in this study were derived from the Longitudinal Health Insurance Database 2005, Taiwan, China. We respectively identified 9988 sodium channel blocker users, 3663 potassium channel blocker users, 65 966 beta-blocker users, 23 366 calcium channel blockers users, and 7031 digoxin users as the study cohorts. The matched comparison cohorts (one comparison subject for each antiarrhythmic drug user) were selected from the same dataset. Each patient was tracked for a 5-year period to define those who were subsequently diagnosed with PCa. After adjusting for sociodemographic characteristics, comorbidities, and age, Cox proportional hazard regressions found that the hazard ratio (HR) of subsequent PCa for sodium channel blocker users was 1.12 (95% confidence interval [CI]: 0.84-1.50), for potassium channel blocker users was 0.89 (95% CI: 0.59-1.34), for beta-blocker users was 1.08 (95% CI: 0.96-1.22), for calcium channel blocker users was 1.14 (95% CI: 0.95-1.36), and for digoxin users was 0.89 (95% CI: 0.67-1.18), compared to their matched nonusers. We concluded that there were no statistical associations between different types of antiarrhythmic drug usage and subsequent PCa risk.

Pharmaceutical Care for Elderly Patients with Atrial Fibrillation Complicated with Digoxin Poisoning / 中国药师

Objective: To explore the role of clinical pharmacists in the treatment of artial fibrillation complicated with digoxin poisoning and the entry points of pharmaceutical care.Methods: Clinical pharmacists participated in the therapy for a patient with atrial fibrillation and digoxin poisoning, monitored the blood concentration of digoxin combined with the characteristics of the patient, analyzed the causes of digoxin poisoning in terms of the underlying diseases, renal function and combined medication, and performed beneficial pharmaceutical care.Results: The suggestions of clinical pharmacists were adopted by doctors, digoxin was withdrawn timely and the drug poisoning was corrected.

Clinical judgement perplexed by initially undisclosed use of herbal medicine and unexpected cross-reactivity of immunoassay

We report a case of symptomatic bradycardia caused by consumption of a Chinese herbal medicine which was initially undisclosed to the attending emergency physician. The scientific name of the herb is Panax japonicus. Electrocardiogram revealed sinus bradycardia. Laboratory tests were normal except for the detection of a high serum digoxin level. Further interrogation of the patient eventually disclosed ingestion of the herb which, however, did not contain any digoxin. Other active ingredients in the herb include various types of ginsenoside. These are digoxin-like substances that had caused the observed false-positive detection of digoxin by fluorescence polarization immunoassay due to cross-reactivity. Our case-report provides an important insight about a blind-spot in the field of laboratory medicine (clinical pathology), namely, the false positive detection of digoxin due to crossreactivity in the immunoassay when we come across digoxin-like substances in clinical scenarios, which has barely received attention in the medical literature. It also conveys a clear educational message that with full understanding of the laboratory methodology and its mechanistic rationale there are actually some tricks-of-the-trade that allow us to optimize the specificity of the biochemical tests and the treatment of digoxin-like substances overdose.

Effect of digoxin on apoptosis and growth in human gastric carcinoma SGC7901 cells / 中国病理生理杂志

AIM: To investigate the effect of digoxin on apoptosis and growth in human gastric carcinoma SGC7901 cells and its possible mechanism.METHODS: SGC7901 cells were incubated in the medium containing digoxin at different concentrations for 24 h.CCK-8 assay was employed to detect the anti-tumor effect of digoxin on SGC7901 cells, and IC50 value of digoxin was calculated.Flow cytometry was used to determine the apoptosis and the cell cycle.Western blot was used to analyze the protein levels of c-Src, p-c-Src(Tyr416), Akt, p-Akt(Ser473), ERK1/2 and p-ERK1/2 (Tyr204).The mRNA expression of c-Src was by RT-PCR.RESULTS: As the concentration of digoxin increased, the cell viability was reduced gradually starting at 50 nmol/L digoxin treatment (P<0.05).The cell viability was reduced to the lowest extent by exposure to 500 nmol/L digoxin (P<0.05).The IC50 value of digoxin was 191.45 nmol/L for 24 h.After treatment with 200 nmol/L digoxin for 24 h, the apoptotic rate and the proportion of G0/G1 phase were significantly increased (P<0.05), the phosphorylated levels of c-Src, ERK1/2 and Akt declined (P<0.05), the mRNA and protein levels of c-Src were down-regulated (P<0.05) and the ability of migration was weaker (P<0.05) than that in control group.CONCLUSION: Digoxin may suppress the growth and induce the apoptosis of human gastric carcinoma SGC7901 cells by inhibiting the expression of c-Src gene and down-regulating the phosphorylated levels of ERK1/2 and Akt.