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The gut microbiota modifies endogenous primary bile acids (BAs) to produce exogenous secondary BAs, which may be further metabolized by cytochrome P450 enzymes (P450s). Our primary aim was to examine how the host adapts to the stress of microbe-derived secondary BAs by P450-mediated oxidative modifications on the steroid nucleus. Five unconjugated tri-hydroxyl BAs that were structurally and/or biologically associated with deoxycholate (DCA) were determined in human biologic samples by liquid chromatography-tandem mass spectrometry in combination with enzyme-digestion techniques. They were identified as DCA-19-ol, DCA-6ß-ol, DCA-5ß-ol, DCA-6α-ol, DCA-1ß-ol, and DCA-4ß-ol based on matching in-laboratory synthesized standards. Metabolic inhibition assays in human liver microsomes and recombinant P450 assays revealed that CYP3A4 and CYP3A7 were responsible for the regioselective oxidations of both DCA and its conjugated forms, glycodeoxycholate (GDCA) and taurodeoxycholate (TDCA). The modification of secondary BAs to tertiary BAs defines a host liver (primary BAs)-gut microbiota (secondary BAs)-host liver (tertiary BAs) axis. The regioselective oxidations of DCA, GDCA, and TDCA by CYP3A4 and CYP3A7 may help eliminate host-toxic DCA species. The 19- and 4ß-hydroxylation of DCA species demonstrated outstanding CYP3A7 selectivity and may be useful as indicators of CYP3A7 activity.
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Citocromo P-450 CYP3A/metabolismo , Ácido Desoxicólico/metabolismo , Microbioma Gastrointestinal/fisiología , Adulto , Ácido Desoxicólico/sangre , Ácido Desoxicólico/toxicidad , Ácido Desoxicólico/orina , Femenino , Voluntarios Sanos , Humanos , Hidroxilación , Hígado/metabolismo , Masculino , Microsomas Hepáticos , Oxidación-Reducción , Adulto JovenRESUMEN
White spot syndrome virus (WSSV) is a large nuclear-replicating DNA virus of crustaceans such as shrimp and crayfish; however, the molecular mechanisms facilitating its transport from the invasion site to the cell nucleus have not yet been well elucidated. In this study, a CqProfilin (CqPFN) with a conserved PROF domain was identified from the red claw crayfish Cherax quadricarinatus. CqPFN was ubiquitously expressed in all examined tissues and hemocyte, with the highest levels in the hemocyte, followed by hematopoietic tissue (Hpt) from which the hemocyte were derived in crayfish. The transcript of WSSV genes such as IE1 and VP28 was obviously decreased both in vivo in hemocyte and Hpt, as well as in vitro in cultured Hpt cells, after CqPFN gene silencing; in contrast, the expression of viral genes was significantly increased by the introduction of a recombinant CqPFN protein in Hpt cells in vitro. Moreover, CqPFN was clearly colocalized with the main viral nucleocapsid protein VP664 and F-actin cytoskeleton, respectively, during the early stage of WSSV infection in Hpt cells. In addition, CqPFN was confirmed to interact with a truncated VP6642,405-2,535 and another viral nucleocapsid protein VP15 of WSSV and Cqß-Actin from Hpt by co-immunoprecipitation assays. Further studies found that VP664 also colocalized with F-actin in the Hpt cell cytoplasm after WSSV infection, suggesting that the actin cytoskeleton was involved in the intracellular transport of incoming viral nucleocapsid. Taken together, CqPFN might combine with the actin cytoskeleton to promote WSSV infection through binding with viral nucleocapsid proteins VP664 and VP15, promoting intracellular transport of viral incoming nucleocapsid for further releasing genome into the nucleus for transcription. Collectively, these results provided an understanding of the WSSV pathogenesis, which will contribute to the development of an antiviral strategy against WSSV disease.
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Exploring and accurately detecting new adulteration markers in sesame oil is an important measure for sesame oil adulteration monitoring. In this study, two endogenous flavors sulfurol and γ-nonalactone which can be used as potential adulteration markers were first discovered in sesame oil and accurately quantified. First, the two endogenous flavors were discovered using gas chromatography-mass spectrometry (GC-MS), and their structures were confirmed by comparing the mass spectrograms with the NIST spectral library. Then the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using direct methanol extraction pretreatment and vanillin-D3 as an internal standard was developed for rapid quantitation and application. The method was successfully validated with recoveries ranging from 88.5% to 102.2% and relative standard deviations between 2.6% and 10.5% (n = 6). The combined method of GC-MS and LC-MS/MS was indicated to be efficient and highly sensitive for detection of sulfurol and γ-nonalactone in edible oil. Subsequently, 31 sesame oils from the market were detected, revealing that 31 samples contained the identified flavors within a relatively consistent range. However, the concentration of these flavor substances in one sample was abnormally high, indicating that there was a potential risk of adulteration. Therefore, the developed method shows good potential for quality evaluation and adulteration screening of sesame oil.
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Contaminación de Alimentos , Cromatografía de Gases y Espectrometría de Masas , Aceite de Sésamo , Espectrometría de Masas en Tándem , Aceite de Sésamo/química , Aceite de Sésamo/análisis , Cromatografía de Gases y Espectrometría de Masas/métodos , Espectrometría de Masas en Tándem/métodos , Contaminación de Alimentos/análisis , Cromatografía Liquida/métodos , Aromatizantes/análisis , Aromatizantes/química , Lactonas/análisis , Lactonas/químicaRESUMEN
Nanoscale zerovalent iron (nZVI)-based nanotechnologies are increasingly being used for environmental remediation; however, the fate and ecotoxicologic effects of nZVI remain unclear. Larvae of medaka fish (Oryzias latipes) underwent 3-14 days' aqueous exposure to thoroughly characterized solutions containing carboxymethyl cellulose (CMC)-stabilized nZVI, bare nZVI, nanoscale iron oxide (nFe(3)O(4)) or ferrous ion [Fe(II)(aq)] at µg/L-mg/L levels to assess the causal toxic effect(s) of iron nanoparticles (NPs). Acute larval mortality was decreased in the order of Fe(II)(aq) > CMC-nZVI > nZVI > nFe(3)O(4). CMC-nZVI (100 mg/L) increased hypoxia and reactive oxygen species (ROS) and Fe(II)(aq) production, thus increasing mortality and oxidative stress response as compared with unstabilized nZVI. Additionally, nFe(3)O(4) and nZVI were more bioavailable than suspended CMC-nZVI or Fe(II)(aq). Antioxidant activities were significantly altered by induced intracellular ROS levels in larvae with subchronic exposure to nFe(3)O(4) or Fe(II)(aq) at environmentally relevant concentrations (0.5-5 mg/L). We report on different organizational biomarkers used for rapidly assessing the lethal and sublethal toxicity of nZVI and its stabilized or oxidized products. The toxicity results implicate a potential ecotoxicological fate and impact of nZVI on the aquatic environment.
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Hierro/toxicidad , Oryzias/metabolismo , Animales , Disponibilidad Biológica , Hierro/química , Hierro/farmacocinética , Nanopartículas del Metal , Oryzias/crecimiento & desarrolloRESUMEN
OBJECTIVE: To study the clinical features of children diagnosed with anti-NMDAR encephalitis in southern China. METHODS: Clinical data of children diagnosed with anti-NMDAR encephalitis from October 2014 to June 2020 from one national regional medical center were analyzed. Neurological disability was assessed by modified Rankin Scale (mRS) throughout the course of disease. RESULTS: 111 children (M/Fâ¯=â¯49/62; mean onset ageâ¯=â¯6.8 y) with anti-NMDAR encephalitis were involved. Prodromal events occurred in 34.2% of patients with infectious events being the most common. Seizure was the most common initial symptom, though movement disorder served as the most common event throughout the course of disease. 9.9% of patients had overlapped with other neuronal autoantibodies. Electroencephalogram showed abnormalities with slow wave (100.0%), epileptic discharge (31.5%) and delta brush (8.1%) respectively. 41.4% of patients had abnormal brain MRI, with focal lesions being the most common. None patients had tumor. 80.9% of patients had good response to first line therapy (steroid plus immunoglobulin), while 14 patients accepted second-line therapy (Rituximab) and all had a good response. Boys were significantly more likely to need more course of steroid. 13.8% of patients relapsed. 2 male patients died. mRS score was significantly improved after treatment. 51.4% of patients had a full recovery and 81.7% had mRS scoreâ¯≤â¯2. The median mRS score of boys after treatment was higher than that of girls. Non-infectious prodromal event, past medical history, perivascular lesions in brain MRI, hospital stay, initial mRS score higher than 3, and RTX treatment were independent risk factors associated with poor prognosis, defined as mRS scoreâ¯>â¯2. CONCLUSION: Of pediatric anti-NMDAR encephalitis in southern China: median onset age around 7â¯years; girls more common; boys might have poor outcome than girls; seizure or movement disorder respectively being most common onset or course symptom; a few overlapped with other neuronal autoantibodies; rare combined with tumor; most had a good response to immunotherapy and a good prognosis; relapse rate relatively high; fatality rate relatively low; some risk factors associated with poor prognosis.
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Encefalitis Antirreceptor N-Metil-D-Aspartato , Encefalitis Antirreceptor N-Metil-D-Aspartato/complicaciones , Encefalitis Antirreceptor N-Metil-D-Aspartato/fisiopatología , Encefalitis Antirreceptor N-Metil-D-Aspartato/terapia , Niño , China , Femenino , Humanos , MasculinoRESUMEN
The ultrasonic transmission spectrum in a double-layered bonded structure is related closely to its interfacial stiffness. Consequently, researching the regularity of the transmission spectrum is of significant interest in evaluating the integrity of the bonded structure. Based on the spring model and the potential function theory, a theoretical model is developed by the transfer matrix method to predict the transmission spectrum in a double-layered bonded structure. Some shift rules of the transmission peaks are obtained by numerical calculation of this model with different substrates. The results show that the resonant transmission peaks move towards a higher frequency with the increase of the normal interfacial stiffness, and each of them has different movement distances with the increasing interfacial stiffness. Indeed, it is also observed that the movement starting points of these peaks are at the specific frequency at which the thickness of either substrate plate equals an integral multiple of half a wavelength. The results from measuring the bonding specimens, which have different interfacial properties and different substrates in this experiment, are utilized to verify the theoretical analysis. Though the theory of "starting points" is not demonstrated effectively, the shift direction and distance exactly match with the result from the theoretical algorithm.
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A surveillance system has been put in place in the Zhejiang province since achieving there the criteria for transmission interruption of schistosomiasis japonica. Suspected patients and special high-risk groups (e.g. the so called 'floating population' and children under 14 years of age) are screened for Schistosoma japonicum using serological tests. Those with positive serological result are subjected to faecal examination and if S. japonicum eggs are found they are treated with praziquantel and followed by regular re-examination until complete cure, i.e. absence of S. japonicum eggs in faecal samples. Patients with advanced schistosomiasis japonica are continuously followed-up. Implementation of the surveillance system from 1995 to 2002 detected two S. japonicum-infected persons; one came from Anhui province and the other from Jiangsu province, but no new infection occurred among local residents. The number of patients with advanced schistosomiasis japonica decreased from 1524 in 1995 to 906 by the end of 2002; a reduction of 40.6%. However, post-transmission schistosomiasis still continues to weigh on the medial resources. We conclude that the surveillance system in Zhejiang province is effective and a useful means for monitoring the endemic situation of schistosomiasis. Hence, it is recommended to be pursued in the years to come.
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Esquistosomiasis Japónica/prevención & control , Adulto , Anciano , Anciano de 80 o más Años , China , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sistema de Registros , Esquistosomiasis Japónica/parasitología , Esquistosomiasis Japónica/transmisión , Esplenectomía , Esplenomegalia/parasitologíaRESUMEN
PURPOSE: This study was designed to identify the incidence and independent perioperative risk factors associated with postoperative delirium of patients who underwent coronary artery bypass grafting (CABG) in a large intensive care unit setting in China. METHODS: Delirium was diagnosed by the confusion assessment method for the intensive care unit (CAM-ICU). Baseline demographics, perioperative data, and postoperative outcomes of 249 consecutive patients who underwent CABG were recorded prospectively and analyzed via univariate analysis and multivariate logistic regression to determine the independent risk factors of postoperative delirium. RESULTS: Postoperative delirium was detected in 76 patients according to CAM-ICU criteria. The incidence was 30.52%. Patients with and without delirium differed significantly on 34 variables (P < .05). Multivariate logistic regression analysis revealed that preoperative atrial fibrillation (odds ratio [OR], 3.957; 95% confidence interval [CI], 1.727-9.066), elevated European system for cardiac operative risk evaluation (OR, 1.178; 95% CI, 1.018-1.364), cognitive impairment (OR, 3.231; 95% CI, 1.008-10.356), prolonged surgery duration (OR, 1.008; 95% CI, 1.003-1.014), postoperative poor quality of sleep (OR, 5.001; 95% CI, 2.476-10.101), and electrolyte disturbance (OR, 2.095; 95% CI, 1.041-4.216) were independently associated with postoperative delirium after CABG. CONCLUSIONS: Delirium is a frequent complication. Factors independently associated with delirium are preoperative atrial fibrillation, elevated European system for cardiac operative risk evaluation and cognitive impairment, longer surgery duration, postoperative poor quality of sleep, and electrolyte disturbance. The study may be helpful in decreasing the incidence of postoperative delirium after CABG by treating these predictors properly.
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Puente de Arteria Coronaria/efectos adversos , Delirio/etiología , Complicaciones Posoperatorias , Anciano , Fibrilación Atrial/etiología , China/epidemiología , Estudios de Cohortes , Delirio/diagnóstico , Delirio/epidemiología , Femenino , Humanos , Incidencia , Unidades de Cuidados Intensivos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Complicaciones Posoperatorias/epidemiología , Estudios Prospectivos , Medición de Riesgo , Factores de Riesgo , Factores de TiempoRESUMEN
In this study, we made use of the discrete active contour model to overcome the natural properties of ultrasound (US) images, speckle, noise and tissue-related textures, to segment the breast tumors precisely. Determination of the real tumor boundary with the snake-deformation process requires an initial contour estimate. However, the manual way to sketch an initial contour is very time-consuming. Thus, we propose an automatic initial contour-finding method that not only maintains the tumor shape, but also is close to the tumor boundary and inside the tumor. During the deformation process, to prevent the snake trapping into the false position caused by tissue-related texture or speckle, we added the edge information as an image feature to define the external force. In addition, because the 3-D volume of a tumor is essentially constructed by a sequence of 2-D images, our method for finding boundaries of a tumor can be extended to 3-D cases. By precisely counting the volume of the 3-D images, we can get the volume of tumor. Finally, we will show that the proposed techniques have rather good performance and lead to a satisfactory result in comparison with the estimated volume and physician's estimate.
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Neoplasias de la Mama/diagnóstico por imagen , Imagenología Tridimensional/métodos , Ultrasonografía Mamaria/métodos , Femenino , Humanos , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: To evaluate the factors influencing the development of portal hypertensive gastropathy (PHG) with liver fibrosis in schistosomiasis japonica. METHODS: A retrospective study was executed on 196 hospitalized patients with schistosomiasis liver fibrosis (109 of them complicated with PHG) from 1998 to 2002. Endoscopic examinations were carried out for all the cases. The analysis was made with a comparison of the PHG incidence to the degree of esophageal varices and the degree of liver function according to Child Pugh's scores. RESULTS: With slight, moderate and severe degree of esophageal varices, the PHG incidence was 47.7%, 54.8%, and 59.1% respectively (P > 0.05). With the Child pugh's classes of A, B and C, the PHG incidence was 56.0%, 53.3%, and 63.6% respectively (P > 0.05). With no surgical intervention, it was 51.3%, and with splenectomy, only 50.0%. With splenectomy plus an operation of transection and an endoscopic sclerotherapy, it was 70.6% and 85.0%. The PHG incidence was significantly higher in the group of splenectomy plus operation of transection and the group with endoscopic sclerotherapy than the group with no surgical intervention (P < 0.05). CONCLUSION: The PHG incidence in schistosomiasis liver fibrosis has no relationship with the degree of esophageal varices and Child Pugh classes of liver function. However, splenectomy plus transection and endoscopic sclerotherapy may accelerate the PHG development.
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Hipertensión Portal/etiología , Cirrosis Hepática/complicaciones , Esquistosomiasis Japónica/complicaciones , Gastropatías/etiología , Anciano , Anciano de 80 o más Años , Várices Esofágicas y Gástricas/complicaciones , Várices Esofágicas y Gástricas/terapia , Femenino , Humanos , Cirrosis Hepática/parasitología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Escleroterapia/efectos adversos , Esplenectomía/efectos adversosRESUMEN
OBJECTIVE: To study the expression of interferon-gamma (IFN-gamma) and type I interferon-y receptor (IFN-gammaRI) in the chronic and advanced patients of schistosomiasis japonica, and to discuss its clinical relationship with hepatic fibrosis. Methods IFN-yR1 in the peripheral blood lymphocytes was detected by ELISA, and the hyaluronic acid (HA) , collagen type IV (C-IV), procollagen type III (PC III), laminin (LN) were detected by radio-immunoassay (RIA) in schistosomiasis patients. The level of IFN-y, IFN-gammaR1 and serum markers of hepatic fibrosis were observed, and the relationship with each other was analyzed by statistical method. RESULTS: There was no difference in the expression of IFN-gamma and IFN-gammaR1 between the patients with chronic schistosomiasis and the normal group (P > 0. 05 ), the IFN-gammaR1 in advanced cases without splenectomy was low (P <0. 05) , but IFN-y was high (P < 0. 01). The two indicators in the advanced schistosomiasis patients with splenectomy returned to normal. There was no corresponding relationship between the two indicators and HA, C-IV, PC III, LN with a r value of 0. 19, 0.20, 0. 14, and 0.21 respectively. CONCLUSION: There is a corresponding relationship between IFN-gamma and IFN-gammaR1; the expression of IFN-gammaR1 is related to the course of schistosomiasis, and the relationship with hepatic fibrosis needs further study.
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Interferón gamma/sangre , Cirrosis Hepática/sangre , Receptores de Interferón/sangre , Esquistosomiasis Japónica/sangre , Adulto , Anciano , Anciano de 80 o más Años , Colágeno Tipo III/sangre , Colágeno Tipo IV/sangre , Femenino , Humanos , Ácido Hialurónico/sangre , Laminina/sangre , Cirrosis Hepática/inmunología , Masculino , Persona de Mediana Edad , Esquistosomiasis Japónica/inmunología , Receptor de Interferón gammaRESUMEN
OBJECTIVE: To explore the correlation between the levels of liver fibrosis and liver fibrosis biochemical parameters of advanced schistosomiasis patients. METHODS: A total of 48 advanced schistosomiasis patients were investigated and they were examined by the liver biopsy and B ultrasound imaging. At the same time, the liver fibrosis biochemical parameters, including glutamine transpeptidase (GGT), alkaline phosphatase (AKP), procollagen III (PC-III), collagen type IV (IV-C), hyaluronic acid (HA) and laminin (LN), were detected. The liver fibrosis levels were classified by the liver biopsy and B ultrasound imaging, respectively, and the correlation between the levels of liver fibrosis and liver fibrosis biochemical parameters were analyzed statistically. RESULTS: There was no correlation between the liver fibrosis levels classified by the liver biopsy and all the liver fibrosis biochemical parameters; there was a weak correlation between the liver fibrosis levels classified by the B ultrasound imaging and GGT, AKP, LN and PC-III, respectively; there was a significant correlation between the liver fibrosis levels classified by the B ultrasound imaging and HA and IV-C, respectively. CONCLUSIONS: B ultrasound examination is a better, noninvasive fibrosis inspection method. Liver fibrosis biochemical parameters combined with the B ultrasound examination may better reflect the overall condition of liver fibrosis.
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Cirrosis Hepática/patología , Esquistosomiasis/complicaciones , Anciano , Anciano de 80 o más Años , Fosfatasa Alcalina/sangre , Biopsia , Colágeno Tipo IV/sangre , Femenino , Humanos , Ácido Hialurónico/sangre , Hígado/patología , Cirrosis Hepática/clasificación , Cirrosis Hepática/complicaciones , Cirrosis Hepática/diagnóstico por imagen , Masculino , Persona de Mediana Edad , UltrasonografíaRESUMEN
The p53 tumor suppressor protein coordinates the cellular responses to a broad range of cellular stresses, leading to DNA repair, cell cycle arrest or apoptosis. The stability of p53 is essential for its tumor suppressor function, which is tightly controlled by ubiquitin-dependent degradation primarily through its negative regulator murine double minute 2 (Mdm2). To better understand the regulation of p53, we tested the interaction between p53 and USP11 using co-immunoprecipitation. The results show that USP11, an ubiquitin-specific protease, forms specific complexes with p53 and stabilizes p53 by deubiquitinating it. Moreover, down-regulation of USP11 dramatically attenuated p53 induction in response to DNA damage stress. These findings reveal that USP11 is a novel regulator of p53, which is required for p53 activation in response to DNA damage.
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Daño del ADN , Tioléster Hidrolasas/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Ubiquitina/metabolismo , Apoptosis , Ciclo Celular , Línea Celular Tumoral , Cicloheximida/química , Reparación del ADN , Células HEK293 , Humanos , Plásmidos/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Interferencia de ARN , UbiquitinaciónRESUMEN
BACKGROUND: Schistosoma japonicum causes marked liver fibrosis, while lethal syndromes present in advanced schistosomiasis patients. Its management depends on the degree of fibrosis present. PATIENTS AND METHODS: Fifty-two patients were recruited to assess the diagnostic value of bio-markers in patients with advanced schistosomiasis japonica. Fibrosis was assessed in liver biopsies using METAVIR system. The correlation between conventional parameters and significant fibrosis (F2-F4) was assessed using univariate analysis and logistic regression. The method of area under receiver operating characteristic curves (AUROCs) was used as a measurement of diagnostic efficacy. RESULTS: White blood cell counts, platelet counts and albumin (all P<0.05) were significantly lower, while prothrombin time, international normalized ratio (INR), hyaluronic acid (HA), IV collagen and ultrasound fibrosis scores (all P<0.01) were significantly elevated in F2-F4 patients compared with F0-F1 patients. HA and INR were identified as independent predictors by multivariate analysis (P=0.023 and P=0.013, respectively). Of the routine laboratory tests for the diagnosis of significant fibrosis, HA gave the best AUROC of 0.875 (95% confidence interval (CI): 0.701-0.997). We constructed a new simple index (INR×HA/100) to discriminate between F2-F4 patients and F0-F1 patients. It showed the highest AUROC of 0.921 (95% CI: 0.828-1.000), and had better diagnostic values than APRI and FIB-4. CONCLUSION: HA and INR were reliable markers for differentiating significant liver fibrosis in patients with advanced schistosomiasis japonica. And the new simple index can easily predict significant liver fibrosis with a high degree of accuracy.
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Cirrosis Hepática/diagnóstico , Schistosoma japonicum/fisiología , Esquistosomiasis Japónica/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Animales , Área Bajo la Curva , Biomarcadores/sangre , Biopsia , Demografía , Femenino , Humanos , Ácido Hialurónico/análisis , Relación Normalizada Internacional , Hígado/patología , Cirrosis Hepática/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Curva ROC , Reproducibilidad de los Resultados , Esquistosomiasis Japónica/diagnóstico , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Factores de Tiempo , UltrasonografíaRESUMEN
The anticancer activity of DNA intercalators is related to their ability to intercalate into the DNA duplex with high affinity, thereby interfering with DNA replication and transcription. Polyamines (spermine in particular) are almost exclusively bound to nucleic acids and are involved in many cellular processes that require nucleic acids. Until now, the effects of polyamines on DNA intercalator activities have remained unclear because intercalation is the most important mechanism employed by DNA-binding drugs. Herein, using actinomycin D (ACTD) as a model, we have attempted to elucidate the effects of spermine on the action of ACTD, including its DNA-binding ability, RNA and DNA polymerase interference, and its role in the transcription and replication inhibition of ACTD within cells. We found that spermine interfered with the binding and stabilization of ACTD to DNA. The presence of increasing concentrations of spermine enhanced the transcriptional and replication activities of RNA and DNA polymerases, respectively, in vitro treated with ActD. Moreover, a decrease in intracellular polyamine concentrations stimulated by methylglyoxal-bis(guanylhydrazone) (MGBG) enhanced the ACTD-induced inhibition of c-myc transcription and DNA replication in several cancer cell lines. The results indicated that spermine attenuates ACTD binding to DNA and its inhibition of transcription and DNA replication both in vitro and within cells. Finally, a synergistic antiproliferative effect of MGBG and ACTD was observed in a cell viability assay. Our findings will be of significant relevance to future developments in combination with cancer therapy by enhancing the anticancer activity of DNA interactors through polyamine depletion.