RESUMEN
The application of day surgery on thoracic surgery is just started, and the innovation of surgical robots and their application on thoracic surgery bring new opportunities to the development of thoracic day surgery. However, the clinical practice of robot-assisted thoracic day surgery (RTDS) in China still has challenges and disagreements. Based on the experience of domestic experts in the field of RTDS clinical practice, this review discussed several key points of RTDS, including the future direction of RTDS, adjusting the indications according to their own conditions for the institutions carrying out RTDS, the robot-assisted advantage of RTDS being brought into play during the operation, and the perfect post-discharge follow-up mechanism being an important guarantee for the safe development of RTDS, to promote the application progress of RTDS in China.
Asunto(s)
Procedimientos Quirúrgicos Robotizados , Cirugía Torácica , Cuidados Posteriores , Procedimientos Quirúrgicos Ambulatorios , China , Humanos , Alta del PacienteRESUMEN
Objective: To investigate the association between hyponatremia and hemodynamic and prognosis in patients with intermediate-risk acute pulmonary embolism. Methods: We retrospectively recruited 110 intermediate-risk acute pulmonary embolism patients (right ventricular dysfunction was confirmed by echocardiography and CT scan with or without the elevated levels of cardiac injury biomarkers) in the first and the second affiliated hospital of Harbin medical university from January 1,2011 to December 31, 2014. The patients were aged (58.4±14.9) years old.There were 49 males and 61 females.Patients were divided into 2 groups as non-hyponatremia group (plasma sodium>135 mmol/L, 93 cases) and hyponatremia group (plasma sodium≤135 mmol/L, 17 cases). Baseline clinical and hemodynamic parameters were obtained from these patients. All enrolled patients were followed up after discharge. Results: Heart rate ((106.7±21.9) beats per minute vs. (93.4±19.4) beats per minute, P=0.043),N-terminal pro B type natriuretic peptide (NT-proBNP, (5 561±1 593) ng/L vs. (1 738±589) ng/L, P=0.005), mean pulmonary arterial pressure((42.6±12.6)mmHg(1 mmHg=0.133 kPa) vs. (33.9±13.3)mmHg, P=0.046), mean right atria pressure ((20.6±8.1)mmHg vs. (10.2±5.4)mmHg, P=0.014), systolic right atria pressure ((27.3±9.0)mmHg vs. (15.6±6.1)mmHg,P=0.013) and diastolic right atria pressure(6.5(4.3,15.5)mmHg vs. 5.0(2.0,8.0)mmHg,P=0.016) were significantly higher in hyponatremia group than in non-hyponatremia group,and systolic blood pressure was significantly lower in hyponatremia group than in non-hyponatremia group ((113.5±21.9)mmHg vs.(129.5±28.9)mmHg, P=0.048). Pearson correlation analysis showed that hyponatremia was negatively correlated with heart rate (r=-0.262, P=0.043), NT-proBNP (r=-0.227, P=0.048), mean pulmonary arterial hypertension (r=-0.259, P=0.046), mean right ventricular pressure (r=-0.296, P=0.047), mean right atria pressure (r=-0.550, P=0.001), systolic right atria pressure (r=-0.552, P=0.001), and diastolic right atria pressure (r=-0.542, P=0.001). Kaplan-Meier survival analysis showed that the 1-year, 2-year and 3-year cumulative survival rates were 76.5%,70.6%,and 64.7% in the hyponatremia group, and 90.3%,86.0%,and 83.9% in the non-hyponatremia group(log-rank test, P=0.036).Multivariate Cox regression analysis showed that hyponatremia was an independent risk factor of death of intermediate-risk pulmonary embolism patient(HR=4.126, 95%CI 1.982-11.343, P=0.036). Conclusion: Hyponatremia is associated with adverse hemodynamic and reduced survival in patients with intermediate-risk pulmonary embolism.
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Hiponatremia , Embolia Pulmonar , Adulto , Anciano , Femenino , Hemodinámica , Humanos , Hiponatremia/complicaciones , Masculino , Persona de Mediana Edad , Péptido Natriurético Encefálico/sangre , Fragmentos de Péptidos , Pronóstico , Embolia Pulmonar/complicaciones , Estudios RetrospectivosRESUMEN
Blumea balsamifera DC is a member of the Compositae family and is frequently used as traditional Chinese medicine. Blumea balsamifera is rich in monoterpenes, which possess a variety of pharmacological activities, such as antioxidant, anti-bacteria, and anti-viral activities. Farnesyl diphosphate synthase (FPS) is a key enzyme in the biosynthetic pathway of terpenes, playing an important regulatory role in plant growth, such as resistance and secondary metabolism. Based on the conserved oligo amino acid residues of published FPS genes from other higher plant species, a cDNA sequence, designated BbFPS, was isolated from B. balsamifera DC using polymerase chain reaction. The clones were an average of 1.6 kb and contained an open reading frame that predicted a polypeptide of 342 amino acids with 89.07% identity to FPS from other plants. The deduced amino acid sequence was dominated by hydrophobic regions and contained 2 highly conserved DDxxD motifs that are essential for proper functioning of FPS. Phylogenetic analysis indicated that FPS grouped with other composite families. Prediction of secondary structure and subcellular localization suggested that alpha helices made up 70% of the amino acids of the sequence.
Asunto(s)
Asteraceae/enzimología , Asteraceae/genética , Genes de Plantas , Geraniltranstransferasa/genética , Análisis de Secuencia de ADN , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Evolución Molecular , Geraniltranstransferasa/química , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Estructura Secundaria de Proteína , Alineación de Secuencia , Análisis de Secuencia de ProteínaRESUMEN
PURPOSE: This study aimed to compare the differences between the Zeiss IOL Master and Oculus Pentacam in keratometry and central anterior chamber depth (ACD) measurements in patients with high myopia and cataracts. METHODS: Between January 2019 and December 2020, 89 patients (103 eyes) with cataracts and high myopia who underwent preoperative cataract evaluation at Nanchang First Hospital were selected for retrospective analysis. Keratometry (K1, K2) and ACD were measured with the IOL Master and Pentacam. Paired t-tests were performed to compare the differences, while the Bland-Altman method was used to evaluate the agreement. RESULTS: The K1 value was (43.15±2.44) D for the IOL Master and (42.98±2.47) D for the Pentacam, and the difference between the two instruments was statistically significant (P<0.01). The K2 value was (44.55±2.63) D for the IOL Master and (44.32±2.55) D for the Pentacam. The ACD was (3.44±0.33)mm for the IOL Master and (3.39±0.36)mm for the Pentacam. There were statistically significant differences between the two instruments in both keratometry and ACD (P<0.01). The absolute values of the maximum difference between the two instruments for K1 and K2 were 1.1 and 1.07; thus, the consistency of the two instruments with respect to this measurement was poor. However, the absolute value of the maximum difference between the two instruments for ACD was 0.34, so the consistency of the two instruments in relation to this measurement was good. CONCLUSIONS: Both the IOL Master and the Pentacam can be used in the measurement of keratometry and ACD in patients with high myopia and cataracts, but the keratometry measurements should be compared in clinical application.
Asunto(s)
Catarata , Miopía , Humanos , Catarata/diagnóstico , Catarata/patología , Masculino , Femenino , Estudios Retrospectivos , Persona de Mediana Edad , Anciano , Miopía/diagnóstico , Miopía/patología , Adulto , Segmento Anterior del Ojo/diagnóstico por imagen , Segmento Anterior del Ojo/patología , Cámara Anterior/patología , Cámara Anterior/diagnóstico por imagen , Extracción de Catarata , Anciano de 80 o más AñosRESUMEN
All patients with urine culture-confirmed genitourinary tuberculosis (GUTB) diagnosed between 1995 and 2007 at two medical centers in northern Taiwan were included in this retrospective study. Genotypes of 48 preserved Mycobacterium tuberculosis (MTB) isolates from these patients were determined by spoligotyping and double repetitive element PCR (DRE-PCR) analysis. Among the 64 patients, 38 (59.4%) were male with a mean ±SD age of 60.3 ± 16.1 years old. The overall mortality rate was 26.2%. Poor prognostic factors included age over 65 years (HR = 4.03; 95%; CI: 1.27-12.76), cardiovascular disease (HR = 5.96; 95% CI: 1.98-17.92), receiving steroids (HR = 10.16; 95% CI: 2.27-45.47), not being treated (HR 4.81; 95% CI 1.12-20.67). Spoligotyping and DRE-PCR of the 48 MTB isolates revealed that 20 (41.7%) belonged to the Beijing family and 40 (83.3%) had a clustering pattern. Identification of a Beijing family isolate was not correlated with drug resistance or mortality. Clustering strains were likely to be resistant to isoniazid (OR = 4.71; 95% CI: 1.10 to 23.53). In this study of patients with urine culture-confirmed GUTB, age and coexisting diseases were independently associated with an unfavorable outcome. The Beijing family was the dominant genotype of GUTB isolates, but did not correlate with drug resistance or outcome.
Asunto(s)
Mycobacterium tuberculosis , Tuberculosis Urogenital , Orina/microbiología , Anciano , Antituberculosos/uso terapéutico , Técnicas de Tipificación Bacteriana , Farmacorresistencia Bacteriana Múltiple , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Pronóstico , Estudios Retrospectivos , Taiwán , Resultado del Tratamiento , Tuberculosis Urogenital/diagnóstico , Tuberculosis Urogenital/microbiología , Tuberculosis Urogenital/mortalidadRESUMEN
Objective: To find out the dietary patterns and explore the relationship between environmental factors (especially dietary patterns) and diabetes mellitus in the adults of Fujian. Methods: Multi-stage sampling method were used to survey residents aged ≥18 years by questionnaire, physical examination and laboratory detection in 10 disease surveillance points in Fujian. Factor analysis was used to identify the dietary patterns, while logistic regression model was applied to analyze relationship between dietary patterns and diabetes mellitus, and classification tree model was adopted to identify the influencing factors for diabetes mellitus. Results: There were four dietary patterns in the population, including meat, plant, high-quality protein, and fried food and beverages patterns. The result of logistic analysis showed that plant pattern, which has higher factor loading of fresh fruit-vegetables and cereal-tubers, was a protective factor for non-diabetes mellitus. The risk of diabetes mellitus in the population at T2 and T3 levels of factor score were 0.727 (95%CI:0.561-0.943) times and 0.736 (95%CI: 0.573-0.944) times higher, respectively, than those whose factor score was in lowest quartile. Thirteen influencing factors and eleven group at high-risk for diabetes mellitus were identified by classification tree model. The influencing factors were dyslipidemia, age, family history of diabetes, hypertension, physical activity, career, sex, sedentary time, abdominal adiposity, BMI, marital status, sleep time and high-quality protein pattern. Conclusion: There is a close association between dietary patterns and diabetes mellitus. It is necessary to promote healthy and reasonable diet, strengthen the monitoring and control of blood lipids, blood pressure and body weight, and have good lifestyle for the prevention and control of diabetes mellitus.
Asunto(s)
Pueblo Asiatico/estadística & datos numéricos , Diabetes Mellitus/epidemiología , Dieta , Dislipidemias/epidemiología , Conducta Alimentaria , Hipertensión/epidemiología , Estilo de Vida , Adulto , Presión Sanguínea , Diabetes Mellitus/etnología , Diabetes Mellitus/etiología , Encuestas sobre Dietas , Dislipidemias/complicaciones , Ejercicio Físico , Análisis Factorial , Femenino , Frutas , Humanos , Hipertensión/complicaciones , Modelos Logísticos , Masculino , Carne , Persona de Mediana Edad , Factores de Riesgo , Encuestas y Cuestionarios , VerdurasRESUMEN
This study attempts to identify the site(s) of action of N-hydroxy-2-acetylaminofluorene (N-OH-AAF) in relation to its inhibition of rat hepatic nuclear RNA synthesis. Two hr after N-OH-AAF injection (3 mg/100 g body weight), rat hepatic nuclear synthesis and nucleolar RNA synthesis in vitro were inhibited by 60 and 80%, respectively. When total nuclear RNA polymerases were solubilized and assayed in the presence of alpha-amanitin (3.2 mug/ml), only alpha-amanitin-sensitive activity was reduced (50%) by N-OH-AAF. Diethylamino-ethyl-Sephadex column chromatography confirmed this finding and further demonstrated that RNA polymerase II was the activity selectively inhibited. Since N-OH-AAF dramatically inhibited nucleolar RNA synthesis but had little effect on RNA polymerase I activity, per se, we therefore concluded that, in addition to its direct inhibitory effect on the enzymic function of RNA polymerase II, N-OH-AAF must also cause impairment of the nucleolar DNA template function.
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Núcleo Celular/metabolismo , Fluorenos/farmacología , Hidroxiacetilamino Fluoreno/farmacología , Hígado/metabolismo , ARN/biosíntesis , Transcripción Genética/efectos de los fármacos , Amanitinas/farmacología , Animales , Nucléolo Celular/metabolismo , Cromatografía por Intercambio Iónico , ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , Dactinomicina/farmacología , Masculino , RatasRESUMEN
The effect of methylazoxymethanol acetate on rat liver nuclear and nucleolar RNA synthesis is investigated at various doses (5 to 50 mg/100 g body weight) and for various lengths of time (1 to 24 hr). The results show that this carcinogen is a potent inhibitor of both nuclear and nucleolar RNA synthesis. Like other carcinogens studied previously in this laboratory, e.g., N-hydroxy-2-acetylaminofluorene, aflatoxin B1, and actinomycin D, methylazoxymethanol acetate inhibits RNA synthesis at multiple sites. It impairs chromatin template function and selectively inhibits the activity of RNA polymerase II. Experimental evidence suggests the mechanism of inhibition of RNA polymerase II activity is due to a decrease in catalytic efficiency rather than in the total number of the enzyme. In addition, it is found that methylazoxymethanol acetate induces a dramatic condensation of nucleoplasmic chromatin.
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Compuestos Azo/farmacología , Hígado/efectos de los fármacos , Acetato de Metilazoximetanol/farmacología , ARN/biosíntesis , Animales , Nucléolo Celular/efectos de los fármacos , Nucléolo Celular/metabolismo , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Relación Dosis-Respuesta a Droga , Hígado/metabolismo , Masculino , ARN Polimerasa II/antagonistas & inhibidores , Ratas , Ratas Endogámicas , Factores de TiempoRESUMEN
Rat liver nuclear RNA polymerases exist in two functional states, one of which is active towards the endogenous chromatin template (engaged enzyme), while the other is inactive (free enzyme) (Yu, F.L. (1974) Nature 251, 344-346). This paper reports the direct separation of these two populations of RNA polymerases from isolated rat liver nuclei by a simple extraction procedure. It is estimated that as much as 50% of the total nuclear RNA polymerase activity in normal rat liver may exist in the form of the free enzyme. Evidence is also presented to indicate that the free enzyme activity is easily lost when the nuclear isolation procedure involves the use of an isotonic buffer medium, or when the isolated nuclei are subjected to sonication as is required for the solubilization of the nuclear RNA polymerases by the conventional method. Based on these new findings, it is proposed that nuclei be isolated directly in hypertonic sucrose and that the free enzyme be extracted before the nuclei are subjected to sonication to solubilize the engaged enzyme. This method circumvents the loss of the free RNA polymerase population and, as a result, the total yield of the nuclear RNA polymerases is greatly increased. The possible functional role of the free RNA polymerase in gene expression is discussed.
Asunto(s)
Núcleo Celular/enzimología , ARN Polimerasas Dirigidas por ADN/aislamiento & purificación , Hígado/enzimología , Animales , ARN Polimerasas Dirigidas por ADN/metabolismo , Guanosina Trifosfato/metabolismo , Masculino , Métodos , Concentración Osmolar , Ratas , Solubilidad , Moldes Genéticos , Ultracentrifugación , Nucleótidos de Uracilo/metabolismoRESUMEN
BACKGROUND: Hemophilia A (HA) is an X-linked bleeding disorder caused by deleterious mutations in the coagulation factor VIII gene (F8). To date, F8 mutations have been documented predominantly in European subjects and in American subjects of European descent. Information on F8 variants in individuals of more diverse ethnic backgrounds is limited. OBJECTIVES: To discover novel and rare F8 variants, and to characterize F8 variants in diverse population backgrounds. PATIENTS/METHODS: We analyzed 2535 subjects, including 26 different ethnicities, whose data were available from the 1000 Genomes Project (1000G) phase 3 dataset, for F8 variants and their potential functional impact. RESULTS: We identified 3030 single nucleotide variants, 31 short deletions and insertions (Indels) and a large, 497 kb, deletion. Among all variants, 86.4% were rare variants and 55.6% were novel. Eighteen variants previously associated with HA were found in our study. Most of these 'HA variants' were ethnic-specific with low allele frequency; however, one variant (p.M2257V) was present in 27% of African subjects. The p.E132D, p.T281A, p.A303V and p.D422H 'HA variants' were identified only in males. Twelve novel missense variants were predicted to be deleterious. The large deletion was discovered in eight female subjects without affecting F8 transcription and the transcription of genes on the X chromosome. CONCLUSION: Characterizing F8 in the 1000G project highlighted the complexity of F8 variants and the importance of interrogating genetic variants on multiple ethnic backgrounds for associations with bleeding and thrombosis. The haplotype analysis and the orientation of duplicons that flank the large deletion suggested that the deletion was recurrent and originated by homologous recombination.
Asunto(s)
Factor VIII/genética , Variación Genética/genética , Proyecto Genoma Humano , Alelos , Estudios de Cohortes , Biología Computacional , Etnicidad/genética , Femenino , Frecuencia de los Genes , Estudios de Asociación Genética , Hemofilia A/etnología , Hemofilia A/genética , Humanos , Mutación INDEL , Masculino , Mutación Missense , Polimorfismo de Nucleótido Simple , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Eliminación de Secuencia , Transcripción GenéticaRESUMEN
Escherichia coli RNA polymerase and the endogenous engaged RNA polymerase I were used as specific probes to monitor the physiologically inactive and active nucleolar chromatin template function, respectively. Actinomycin D bound preferentially to the physiologically active regions of rat liver nucleolar chromatin in vivo.
Asunto(s)
Cromatina/metabolismo , Dactinomicina/metabolismo , Animales , Nucléolo Celular/ultraestructura , ARN Polimerasas Dirigidas por ADN/metabolismo , Dactinomicina/farmacología , Escherichia coli/enzimología , Hígado/ultraestructura , Masculino , ARN Polimerasa I/antagonistas & inhibidores , Ratas , Ratas Endogámicas , Transcripción GenéticaRESUMEN
When rat liver nuclear chromatin was sonicated in buffer containing 0.35 M (NH4)2SO4 to release the engaged RNA polymerases, a potent inhibitor was also released. This inhibitor elicited dramatic inhibition of RNA synthesis regardless of whether the free or engaged RNA polymerase was used. On further analysis, it became apparent that the site of inhibition was on the DNA template, not on the enzyme. This inhibitor could be extracted into 0.25 N HCl by the standard procedure for the isolation of histones. This acid-soluble inhibitor, showing typical histone band on gel, was RNase A and DNase I resistant, but was sensitive to both pronase and snake venom phosphodiesterase digestion, as well as to 0.1 N KOH hydrolysis. Furthermore, when [14C]adenine labeled poly-ADP-ribosylated histones were digested by snake venom phosphodiesterase, the release of radioactivity was in parallel to the loss of inhibitor activity. We conclude that the inhibitor substances are poly-ADP-ribosylated histones and propose that the poly-ADP-ribosylated histones rather than the histones are the natural suppressors of the gene.
Asunto(s)
ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , Regulación de la Expresión Génica , Histonas/fisiología , Azúcares de Nucleósido Difosfato/fisiología , Poli Adenosina Difosfato Ribosa/fisiología , Animales , Núcleo Celular/metabolismo , Cromatina/metabolismo , ADN/antagonistas & inhibidores , Electroforesis en Gel de Poliacrilamida , Hígado/metabolismo , Ratas , Ratas Endogámicas , Solubilidad , Moldes GenéticosRESUMEN
Using a PCR technique, exon # 5 of the human tumor suppressor gene p53 was amplified and ligated into the pCRII vector and transformed into Escherichia coli INV alphaF' competent cells. The cloned exon # 5 was 184 bp long. Evidence is presented to show that after dimethyldioxirane epoxidation, 17beta-estradiol was able to form 17beta-estradiol-DNA adducts and to strongly inhibit the replication of the cloned exon # 5 producing smaller sizes of DNA fragments and introducing errors of incorporation at the 3'-end of the terminating DNAs. The errors occurred mainly at the clusters of the complementary 'G' and 'A' bases on the template strand DNA, presumably, the major sites where the 17beta-estradiol-DNA adducts were formed.
Asunto(s)
Aductos de ADN/farmacología , Estradiol/farmacología , Genes p53/efectos de los fármacos , Secuencia de Bases , Clonación Molecular , Electroforesis en Gel de Poliacrilamida , Compuestos Epoxi/farmacología , Exones , Humanos , Datos de Secuencia Molecular , Análisis de Secuencia de ADNRESUMEN
A linearized template, obtained from the vector pGEM-3Zf(+) containing a supF gene fragment, was treated with aflatoxin B1-8,9-epoxide (AFB1 epoxide) and transcription in vitro was then studied. The template functions of both strands of the supF gene were similarly inhibited as shown by transcription with both T7 and SP6 RNA polymerases. This inhibition was dose-dependent and affected the elongation step more extensively than the initiation step. Gel electrophoretic analysis of RNA formed by T7 RNA polymerase indicated that template treated with different AFB1 epoxide doses yielded the same three major truncated RNA fragments. Sequence analysis showed that these major sites of RNA truncation occurred in the vicinity of adjacent guanine residues in the template.
Asunto(s)
Aflatoxina B1/análogos & derivados , Aductos de ADN/metabolismo , ARN de Transferencia/genética , ARN/biosíntesis , Transcripción Genética/efectos de los fármacos , Aflatoxina B1/síntesis química , Aflatoxina B1/metabolismo , Aflatoxina B1/farmacología , Secuencia de Bases , ARN Polimerasas Dirigidas por ADN/efectos de los fármacos , ARN Polimerasas Dirigidas por ADN/metabolismo , Dimetilsulfóxido/farmacología , Genes Supresores , Vectores Genéticos/genética , Datos de Secuencia Molecular , Proteínas ViralesRESUMEN
The effect of dietary fat on breast cancer is a longstanding and an unresolved issue. We found that 17beta-estradiol (E2) could be activated by the epoxide-forming oxidant dimethyldioxirane (DMDO) to bind DNA-forming DNA adducts both in vitro and in vivo, and to inhibit nuclear RNA synthesis. We proposed that E2 epoxidation is the underlying mechanism for the initiation of breast cancer carcinogenesis (Carcinogenesis 17, 1957-61, 1996). This report is on the transcriptional and DNA-binding properties of vegetable oils and fatty acids, and on the potentials of these compounds to prevent the formation of E2 epoxide. The results show that vegetable oils, having no effect on nuclear RNA synthesis either before or after DMDO treatment, were all able to prevent the formation of E2 epoxide independent of their mono- or polyunsaturated fatty acid content. Similarly, unsaturated fatty acids, regardless of chain length and number of double bonds, were all able to prevent the formation of E2 epoxide as reflected by the loss of the ability of [3H]E2 to bind DNA. In contrast to vegetable oils, the results indicated that the unsaturated fatty acids palmitoleic, oleic, linoleic, linolenic and arachidonic acid could be activated by DMDO to inhibit nuclear RNA synthesis, and that the mono-unsaturated fatty acids (i.e. palmitoleic and oleic acid) were stronger inhibitors than fatty acids with more than one double bond (e.g. linoleic, linolenic and arachidonic acid). [32P]Post-labeling analysis revealed that under identical DMDO activation, the DNA adducts formed for oleic acid were 17098 adducts/10(8) nucleotides, which was 20-fold more than palmitoleic acid (815), and 120-fold more than alpha-linolenic acid (142). This result strongly suggests that oleic acid could be a potential initiating carcinogen after epoxidation.
Asunto(s)
Anticarcinógenos/farmacología , Neoplasias de la Mama/prevención & control , Aductos de ADN/metabolismo , Ácidos Grasos Insaturados/farmacología , Aceites de Plantas/farmacología , Animales , Quimioprevención/métodos , Aductos de ADN/efectos de los fármacos , ADN Ribosómico/efectos de los fármacos , ADN Ribosómico/metabolismo , Grasas de la Dieta/farmacología , Estradiol/farmacología , Femenino , Humanos , ARN Mensajero/efectos de los fármacos , ARN Mensajero/metabolismo , Ratas , Sensibilidad y Especificidad , Células Tumorales CultivadasRESUMEN
Estrogens, used widely from hormone replacement therapy to cancer treatment, are themselves carcinogenic, causing uterine and breast cancers. However, the mechanism of their carcinogenic action is still not known. Recently, we found that estrone (E1) and 17beta-estradiol (E2) could be activated by the versatile epoxide-forming oxidant dimethyldioxirane (DMDO), resulting in the inhibition of rat liver nuclear and nucleolar RNA synthesis in a dose-dependent manner in vitro. Since epoxidation is often required for the activation of chemical carcinogens, we proposed that estrogen epoxidation is the underlying mechanism for the initiation of estrogen carcinogenesis (Carcinogenesis 17 (1996) 1957-1961). It is known that initiation requires the binding of a carcinogen to DNA with the formation of DNA adducts. One of the critical tests of our hypothesis is therefore to determine whether E1 and E2 after activation are able to bind DNA. This paper reports that after DMDO activation, [3H]E1 and [3H]E2 were able to bind to both A-T and G-C containing DNAs. Furthermore. the formation of E1-DNA and E2-DNA adducts was detected by 32P-postlabeling analysis.
Asunto(s)
Carcinógenos/química , Aductos de ADN/química , ARN Polimerasas Dirigidas por ADN/metabolismo , ADN/química , Compuestos Epoxi , Estradiol/química , Estrona/química , Estrona/farmacología , Animales , Bovinos , ADN/metabolismo , ARN Polimerasas Dirigidas por ADN/efectos de los fármacos , Cinética , Oxidación-Reducción , Radioisótopos de Fósforo , Polidesoxirribonucleótidos , ARN/biosíntesis , Técnica de Dilución de Radioisótopos , Ratas , Moldes Genéticos , Transcripción Genética/efectos de los fármacosRESUMEN
Rat-liver nucleoli (10-15 micrograms DNA) were digested with either 0.6 or 3 units of DNase I for various times (up to 1 h). RNA synthesis was then measured in the absence or presence of 3 units of Escherichia coli RNA polymerase. It was found that the nucleolar chromatin supporting the endogenous engaged RNA polymerase I transcription was completely destroyed in 3 min with either concentration of DNase I. The nucleolar chromatin template transcribed by E. coli RNA polymerase retained 50% of its original capacity even 60 min after 3 units of DNase I digestion. When hybridization experiments were conducted, it was found that the DNAs derived from both levels of DNase-I-digested nucleoli were incapable of forming hybrids with the labelled nucleolar RNA synthesized by the engaged RNA polymerase I from the untreated nucleoli. Since the engaged RNA polymerase I transcribes only the physiologically active genes of the nucleolar chromatin, and the RNA transcripts represent active gene product, these data suggest that DNase I digestion has completely destroyed the active genes of the nucleolar chromatin, and E. coli RNA polymerase is able to transcribe the inactive nucleolar chromatin template.
Asunto(s)
Nucléolo Celular/metabolismo , Cromatina/metabolismo , ARN Polimerasas Dirigidas por ADN/metabolismo , Escherichia coli/enzimología , Hígado/metabolismo , Transcripción Genética , Animales , ADN/metabolismo , Desoxirribonucleasa I , Desoxirribonucleasas/metabolismo , Endonucleasas/metabolismo , Masculino , Hibridación de Ácido Nucleico , ARN/biosíntesis , ARN Polimerasa I/metabolismo , Ratas , Ratas Endogámicas , Moldes GenéticosRESUMEN
Using mild sonication, nucleoplasmic, nucleolar, and subnucleolar P-3 and S-3 chromatin fractions are isolated from rat liver nuclei. These fractions differ widely (over 80-fold) from each other in transcriptional activity as measured by the chromatin bound engaged RNA polymerases. Chemical analyses indicate that the active chromatin, e.g. P-3 and nucleolar fractions, are rich in RNA and protein as compared to the inactive chromatin, e.g. nucleoplasmic, and S-3 fractions. However, the DNA base content are all the same, showing 40% GC and 60% AT, including P-3 which is enriched in rDNA. Polyacrylamide gel electrophoresis of the 0.25 N HCl extracted proteins shows that all five histones are present in active chromatin. Additionally, the gel reveals two protein bands, one ahead of histone H2B and another ahead of histone H4, that are diminished or missing from the inactive chromatin. On the other hand, there is a fast moving protein band ahead of H4 in the inactive chromatin that is almost absent in the active chromatin. Transcriptional tests using E. coli RNA polymerase and several synthetic DNA templates of known base content and sequence indicate that the 0.25 N HCl soluble protein extracts from active chromatin contain activator proteins which are capable of countering the histone suppressors present in the extracts in a DNA base and sequence specific manner. The data show that although the histone suppressors are able to strongly inhibit the template function of poly[d(A-T)], the protein activators are able to overcome the suppressor activity and stimulate RNA synthesis several-fold when poly(dA).poly(dT) or poly(dT) is used.
Asunto(s)
Núcleo Celular/genética , Cromatina/genética , Hígado/ultraestructura , Transcripción Genética , Animales , Fraccionamiento Químico , Cromatina/química , Histonas/aislamiento & purificación , Ácido Clorhídrico , Técnicas In Vitro , RatasRESUMEN
The [3H]XTPs are used widely to monitor RNA synthesis in vitro. Recently, we discovered that they reflected only 40-45% of the true rate of nuclear RNA synthesis. Thus, when [8-14C]GTP was used, 1466 pmol [8-14C]GMP was incorporated per mg DNA/10 min. On the other hand, when [8-3H]GTP was used, only 564 pmol [8-3H]GMP was incorporated per mg DNA/10 min. There are three obvious factors that could have contributed to this greater than 2-fold difference in the apparent incorporation rate: commercial [8-3H]GTP sample was contaminated with substances causing the assay medium to be less efficient in RNA synthesis; 3H exchange occurred during acid washing of the [3H]RNA; and there was a greater quenching effect on [3H]RNA. Experiments were designed to test each of these alternatives. We are able to conclude that none of the above three are contributing factors. Our data also show that the 3H label was removed after it was incorporated into RNA. Similar differences were observed when 3H and 14C labeled pairs of ATP, UTP and CTP were compared. Furthermore, when nuclei were fractionated into nucleolar and nucleoplasmic fractions and carried out RNA synthesis, the loss of 3H label was observed mainly from the nucleoplasmic fraction.
Asunto(s)
Núcleo Celular/metabolismo , ARN/biosíntesis , Ribonucleótidos/análisis , Animales , Nucléolo Celular/metabolismo , Guanosina Trifosfato/análisis , Guanosina Trifosfato/metabolismo , Técnicas In Vitro , Cinética , Masculino , ARN/análisis , Ratas , Ratas EndogámicasRESUMEN
Ethylcholine mustard aziridinium ion (AF64A), a neurotoxic choline analog, was injected (ICV) bilaterally (1.5 nmol/ventricle, n = 10) into male adult rats to induce a model of Alzheimer's disease (AD). One month later, using NADPH-diaphorase (NADPH-d) histochemistry followed by choline acetyltransferase (ChAT) immunocytochemistry (PAP) on the coronal sections of the septal complex, double-staining experiments were performed to assay the alterations of septal cholinergic neurons coexisted with nitric oxide synthase (NOS). Compared to controls, AF64A can significantly reduce the numbers of ChAT single labelled neurons and NADPH-d + ChAT double labelled neurons in the dorsal subgroup (29.5% and 26.7%, respectively, P < 0.01). Moreover, the dendrites of these neurons were damaged. While administration of AF64A resulted in a significant decrease in the number of ChAT single labelled neurons (35.2%, P < 0.01) in the intermediate subgroup (rostral extension of the nucleus/substantia innominata) NADPH-d + ChAT double labelled neurons were unchanged (P > 0.05). In the midline and the ventral subgroups, both of these two kinds of cholinergic neurons were not affected significantly by AF64A (P > 0.05). Furthermore, AF64A had no effect on NADPH-diaphorase single labelled neurons in all subgroups of septal complex. These results indicate that: (1) the administration of AF64A has different effects on the cholinergic neurons with or without NOS in different subgroups of the septal complex, and the NADPH-d + ChAT double labelled neurons resist the neurotoxicity of AF64A; (2) in the intermediate subgroup, the cholinergic neurons containing NOS may have projections different from those without NOS.