RESUMO
We compare several different methods to quantify the uncertainty of binding parameters estimated from isothermal titration calorimetry data: the asymptotic standard error from maximum likelihood estimation, error propagation based on a first-order Taylor series expansion, and the Bayesian credible interval. When the methods are applied to simulated experiments and to measurements of Mg(II) binding to EDTA, the asymptotic standard error underestimates the uncertainty in the free energy and enthalpy of binding. Error propagation overestimates the uncertainty for both quantities, except in the simulations, where it underestimates the uncertainty of enthalpy for confidence intervals less than 70%. In both datasets, Bayesian credible intervals are much closer to observed confidence intervals.
Assuntos
Incerteza , Teorema de Bayes , Calorimetria/métodos , Termodinâmica , Ligação ProteicaRESUMO
CuO-CeO2 catalysts supported on material synthesized from red mud and rice husk ash (CuO-CeO2/ZRM) were prepared by co-impregnation method. The role of CeO2 additive in the improvement of physicochemical properties and catalytic activity of CuO-CeO2/ZRM catalysts were emphasized. Several techniques, including Brunauer-Emmett-Teller Nitrogen physisorption measurements, X-ray powder diffraction, hydrogen temperature programed reduction, scanning electron microscopy and transmission electron microscopy (TEM) were used to investigate the properties of catalysts. Crystallite size calculated by Scherrer' equation was 17.4 - 21.8 nm. Modification of 5 wt% CuO/ZRM catalyst with CeO2 had reduced the size of the nanoparticles leading to a significant enhancement of the catalytic activity in p-xylene deep oxidation at temperature range of 275 - 400 °C. The 5 wt% CuO/ZRM sample promoted by 3 wt% of nanoparticle CeO2 with the average size of 17.5 nm and BET surface area of 31.3 m2 g-1 exhibited the best activity for p-xylene deep oxidation. In this sample, the conversion of p-xylene reaches to 90% at 350 °C.
Assuntos
Cério/química , Cobre/química , Nanopartículas/química , Oryza/química , Xilenos/análise , Zeolitas/química , Catálise , Oxirredução , Tamanho da Partícula , Caules de Planta/química , Propriedades de Superfície , TemperaturaRESUMO
OBJECTIVE: This study aims to characterize the rate of two specific resistance genes (KPC and NDM-1) and determine the route of transmission between the sites to implement infection control measures effectively. PATIENTS AND METHODS: This study was carried out at Viet Duc hospital in Vietnam. Bacterial isolates (Klebsiella pneumoniae) were collected between January 2018 and June 2019. Bacterial strains and antimicrobial susceptibility testing were performed in the VITEK 2 system. RESULTS: A total of 100 samples from 25 patients were taken. From each patient, we collected 4 samples from 4 sites. 25 isolated strains resisted 100% to amoxicillin/acid clavulanic, piperacillin/Tazobactam, and antibiotics in the cephalosporine group. Particularly in the carbapenem group, they resisted 100% to ertapenem, 96% to imipenem, and eropenem (rest was intermediate level). They have 76% sensitivity to aminoglycosides, 76% to amikacin, 60% to gentamycin, and 60% to tigecycline. Klebsiella pneumoniae carbapenemase (KPC) (+) was 24% and NDM-1 (+) was 28%. There was no case in all four sites. Positive-KPC strains were mainly in two sites (4/6 = 66.67%) and positive-NDM-1 strains were mainly in three sites (4/7 = 57.14%). Negative to both KPC and NDM-1 strains were in one site (4/12 = 33.3%) and two sites (6/12 = 50%). CONCLUSIONS: The rate of KPC and NDM-1 was 24% and 28%. In accordance with high antibiotic resistance rates to common antibiotics used in Vietnam, the high rate of transmission possibility between the sites contributed to strengthen the implementation of infection control measures in the ICU setting.
Assuntos
Infecções por Klebsiella , Klebsiella pneumoniae , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , beta-Lactamases/genética , Proteínas de Bactérias/genética , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Controle de Infecções , Unidades de Terapia Intensiva , Testes de Sensibilidade MicrobianaRESUMO
The initial management of early-stage ovarian cancer consists of staging surgery including pelvic and para-aortic lymphadenectomy. The use of the sentinel lymph node (SLN) procedure in this setting may decrease the morbidity associated with this surgery. The objective of this review was to evaluate the feasibility of the SLN procedure in ovarian cancer diagnosed at an early stage by comparing the different techniques used and their accuracy. A systematic literature search was performed on PubMed and ClinicalTrials.gov for articles in English or French about the SLN technique in ovarian cancer. Ten studies were included in the analysis, with a total of 179 patients. The main tracers used were Technetium-99m, indocyanine green, and patent blue, and the most common site of injection was the proper ovarian and unfundibulopelvic ligaments. The overall detection rate was 87.7%. Of the small number of cases of lymph node metastasis reported, the SLN procedure had a sensitivity of 90.9% and a negative predictive value of 98.8%. The sentinel node procedure appears to be feasible and safe and could be reliable in determining the lymph node status of patients with early-stage ovarian cancer.
Assuntos
Neoplasias Ovarianas , Biópsia de Linfonodo Sentinela , Corantes , Feminino , Humanos , Linfonodos/patologia , Estadiamento de Neoplasias , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/cirurgia , Biópsia de Linfonodo Sentinela/métodosRESUMO
OBJECTIVE: To assess the feasibility and safety of total hysterectomy by laparoscopic approach (± robot assisted) in ambulatory. MATERIALS AND METHODS: French three-center retrospective study including 165 patients who had laparoscopic (± robot assisted) total hysterectomy scheduled as outpatients from January 2016 to December 2020. Clinical and perioperative data were collected. Factors associated with outpatient failure and rehospitalization were evaluated. RESULTS: The outpatient success rate was 92.7%. Factors associated with outpatient failure were incision time>13:00, large volume of blood loss, intraoperative complications with Oslo score≥2, uterine weight≥250g, indication for benign pathology, and robot-assisted approach. Among patients managed as outpatients, 7.2% were rehospitalized at a mean of 10 days from surgery. The factors associated with rehospitalization were the use of an effective antiaggregant or anticoagulant treatment and the use of intraoperative adhesiolysis. Four patients (2.6%) underwent revision surgery. CONCLUSION: Minimally invasive hysterectomy can be performed as an outpatient procedure even in cases of malignant pathology. Age and body mass index are not associated with an increased risk of failure or re-hospitalization within one month.
Assuntos
Laparoscopia , Procedimentos Cirúrgicos Robóticos , Robótica , Procedimentos Cirúrgicos Ambulatórios , Estudos de Viabilidade , Feminino , Humanos , Histerectomia/métodos , Laparoscopia/métodos , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Robótica/métodosRESUMO
Bayesian regression is performed to infer parameters of thermodynamic binding models from isothermal titration calorimetry measurements in which the titrant is an enantiomeric mixture. For some measurements the posterior density is multimodal, indicating that additional data with a different protocol are required to uniquely determine the parameters. Models of increasing complexity-two-component binding, racemic mixture, and enantiomeric mixture-are compared using model selection criteria. To precisely estimate one of these criteria, the Bayes factor, a variation of bridge sampling is developed.
Assuntos
Teorema de Bayes , Calorimetria , TermodinâmicaRESUMO
Raw or undercooked fish dishes are the major sources of human infection of fishborne trematodes (FBT) and the situation of metacercarial infection in fish greatly affect the prevalence in humans, especially those fish that are commonly used for raw consumption. To investigate the situation of infection with metacercaria of FBT in fish often used to prepare raw fish dishes by local people to assess the risk of infection to humans in Ninh Binh province, Vietnam. 345 fish belonging to five species of freshwater and one species of brackish water fish were collected from fishermen or small-scale fish dealers in Kim Son and Yen Khanh districts, Ninh Binh province between May 2017 and May 2018. Metacercaria of FBT was discovered by pepsin and hydrochloric acid digestion techniques and identified by the morphological and molecular analysis. Among examined fish, 44.06% infected with FBT metacercaria and the highest prevalence was in Cyprinus carpio (86.54%), Ctenopharyngodon idellus (78.43%) and Hypophthalmichthys molitrix (66.67%) while Konosirus punctatus - the brackish water fish - were free from infection. Three species of FBT were found; namely Haplorchis pumilio (accounting for 99.84% of collected metacercariae), Haplorchis taichui and Clonorchis sinensis. The average density was 1.06 metacercariae per gram of freshwater fish and the highest number was of C. idellus (6.38 cysts/gram) followed by Cirrhinus molitorella and C. carpio. Results of the study show the high prevalence of infection of FBT metacercariae among freshwater fish often used to prepare raw fish dishes in Ninh Binh province. These findings suggest the need for greater awareness of the risk from raw fish dishes among public health authorities and people.
Assuntos
Doenças dos Peixes/parasitologia , Peixes/parasitologia , Trematódeos/isolamento & purificação , Animais , Clonorchis sinensis/isolamento & purificação , Estudos Transversais , Contaminação de Alimentos , Heterophyidae/isolamento & purificação , Metacercárias , VietnãRESUMO
A fluorescently labeled estradiol, N'-fluoresceino-N'-(17 beta-estradiol hemisuccinamide) thiourea (FE) was used for measuring estrogen receptor content per cell in tumor cells. The cellular content of FE was measured quantitatively by flow cytometry. Binding of FE occurs in the nanomolar concentration range, an indication of the high affinity of the labeled estradiol. Competition of FE for binding sites is observed with estrogens, but not with progestins, androgens, or glucocorticosteroids, indicating the specificity of FE binding. In contrast to other estrogen receptor assays, this new technique requires a small sample size (about 5000 cells) and permits the assessment of heterogeneity in estrogen receptor expression among tumor cells.
Assuntos
Neoplasias da Mama/análise , Citometria de Fluxo , Receptores de Estrogênio/análise , Ligação Competitiva , Linhagem Celular , Estudos de Avaliação como Assunto , Feminino , Humanos , Temperatura , Fatores de TempoRESUMO
The importance of the cuticular layer in regulating a plant's water status and providing protection from environmental challenges has been recognized for a long time. The cuticular layer in plants restricts non-stomatal water loss and protects plants against damage from pathogen infection and UV radiation. Much genetic and biochemical research has been done about cutin and wax transportation in Arabidopsis thaliana, but little is known about it in rice. Here, we report that a rice ATP-binding cassette (ABC) transporter, OsABCG9, is essential for normal development during vegetative growth and could play a critical role in the transportation of epicuticular wax in rice. Rice phenotypes with mutated OsABCG9 exhibited growth retardation and sensitivity to low humidity. The total amount of cuticular wax on the leaves of the osabcg9-1 mutant diminished by 53% compared with the wild type, and wax crystals disappeared completely in osabcg9-2 mutant leaves. However, OsABCG9 does not seem to be involved in cutin transportation, even though its ortholog in Arabidopsis, AtABCG11, transports both wax and cutin. Furthermore, the osabcg9-1 mutant had increased leaf chlorophyll leaching and more severe drought susceptibility. This study provides new insights about differences between rice and A. thaliana in wax and cutin transportation associated with the ABCG family during evolution.
RESUMO
Conditions were established for single cell analysis of glucocorticoid receptor (GR) content by flow cytometry using several clones of a human leukemic cell line (CCRF-CEM). These included CEM-7A, 7R, C1, and ICR 27 Tk.3 cells which were examined both by standard [3H]dexamethasone radiometric binding and by two independent flow cytometry assays. The latter involved either mouse monoclonal antibody against GR (GR-MoAb) or fluoresceinated cortisol ligand probes. For CEM-7A, 7R, and C1 cells, there was a correlation between GR-MoAb and radiometrically defined GR values. However, clone ICR-27 Tk.3 with low [3H]dexamethasone binding exhibited the highest GR-MoAb fluorescence. The fluoresceinated cortisol assay correlated with dexamethasone binding values in all four clones. Thus, GR-MoAb identifies the total immunologically reactive GR present, while the fluoresceinated cortisol assay quantifies only the functionally intact GR in terms of its initial binding. Their combined use may reveal the cellular heterogeneity of GR expression and function also in human tumor samples, to which they have been successfully applied. When coupled with DNA counterstaining, GR expression can be related directly to frequently DNA-aneuploid tumor cells and cell cycle distribution.
Assuntos
Anticorpos Monoclonais , Receptores de Glucocorticoides/análise , Ciclo Celular , Divisão Celular , Linhagem Celular , Células Clonais , Dexametasona/metabolismo , Citometria de Fluxo/métodos , Fluoresceína-5-Isotiocianato , Fluoresceínas , Corantes Fluorescentes , Humanos , Cinética , Receptores de Glucocorticoides/imunologia , TiocianatosRESUMO
The lipophilic anthracycline antibiotic annamycin (Ann) was entrapped in liposomes of different size [median diameter: 1.64 microns, multilamellar liposomal Ann (L-Ann); 0.030 micron, small unilamellar Ann (S-Ann)] with > 90% entrapment efficiency and tested in vitro against four pairs of sensitive and multidrug-resistant (MDR) tumor cell lines and in vivo by the i.v. route in five tumor models: advanced s.c. B16 melanoma; s.c. M5076 reticulosarcoma; lung metastases of Lewis lung carcinoma; and s.c. KB and KB-V1 xenografts in nude mice. Predetermined optimal doses of the different formulations were used and the results were compared with doxorubicin (Dox). In vitro, Ann, either in suspension in 10% dimethyl sulfoxide (F-Ann) (1 mg/ml) or entrapped in liposomes, was able to partially overcome resistance in all four pairs of sensitive and MDR KB, 8226, P388, and CEM cell lines (resistance indexes 63, 269, 333, and 356 for Dox versus 4, 5, 19, and 8.7 for L-Ann, respectively). In vivo, both F-Ann and liposome-entrapped Ann were slightly more effective than Dox in inhibiting the growth of advanced s.c. B16 melanoma tumors. L-Ann was markedly more effective than Dox and moderately more effective than F-Ann in prolonging the life span of animals bearing s.c. M5076 and lung metastases of Lewis lung carcinoma tumors. All drugs were equally effective at optimal doses in delaying the growth of s.c. KB xenografts, whereas all Ann formulations were markedly more effective than Dox in delaying the growth of s.c. KB-V1 (MDR) xenografts. In all in vivo experiments, S-Ann was consistently more effective than L-Ann and L-Ann was more effective than F-Ann. These results indicate that (a) Ann is more effective than Dox by the i.v. route against several tumor models and that MDR tumors are partially not cross-resistant to Ann both in vitro and in vivo, (b) liposomes enhance the in vivo antitumor properties of Ann, and (c) small liposomes are more effective than large liposomes in enhancing Ann antitumor activity.
Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacologia , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Doxorrubicina/análogos & derivados , Animais , Antibióticos Antineoplásicos/toxicidade , Antineoplásicos/toxicidade , Fenômenos Químicos , Físico-Química , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacologia , Doxorrubicina/toxicidade , Resistência a Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Células KB , Leucemia P388/tratamento farmacológico , Leucemia P388/metabolismo , Lipossomos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Masculino , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Transplante de Neoplasias , Fenótipo , Células Tumorais CultivadasRESUMO
We recently demonstrated that C-CAM, an epithelial-cell adhesion molecule of the immunoglobulin supergene family, could be regulated by androgen and might act as a growth repressor during differentiation of the prostatic epithelium. To define the role of C-CAM in prostatic tumorigenesis, a tumorigenic human prostatic cancer cell line, PC-3, was transfected with an expression plasmid containing C-CAM1 (a C-CAM isoform). Transfected clones showed significantly lower growth rates, reduced anchorage-independent growth, and less tumorigenicity in vivo than control cells. Furthermore, transfection of an antisense vector into a nontumorigenic prostatic epithelial cell line, NbE, resulted in tumor formation in nude mice. Sublines derived from these NbE-induced tumors had lower levels of C-CAM than did control cells. These data suggest that C-CAM1 can function as a tumor suppressor in prostate tumorigenesis.
Assuntos
Adenosina Trifosfatases/fisiologia , Moléculas de Adesão Celular/fisiologia , Neoplasias da Próstata/metabolismo , Animais , Antígenos CD , Antígeno Carcinoembrionário , Divisão Celular , Glicoproteínas , Humanos , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Transfecção , Células Tumorais CultivadasRESUMO
We have previously reported that fludarabine, an adenine nucleoside analogue, significantly enhances radiation-induced tumor regrowth delay and local cure in several mouse tumors. Although fludarabine potentiated tumor regrowth delay at various times from -36 h to +6 h in a SA-NH mouse sarcoma model, the greatest enhancement was observed when fludarabine was administered 24 h before irradiation. The purpose of this study was to understand the basis for in vivo enhancement of radiation efficacy by fludarabine. To examine the effect of fludarabine on DNA synthesis and cell cycle progression, tumor-bearing mice were given fludarabine by an i.p. route and then bromodeoxyuridine at various times up to 36 h, followed 0.5 h later by tumor harvest. Two-parameter flow cytometry analysis of the tumor cells using an anti-bromodeoxyuridine antibody demonstrated that an 800-mg/kg fludarabine dose stops DNA synthesis within 3 h with recovery starting at 12 h. By 24 h after fludarabine treatment, a synchronized wave of cycling tumor cells appeared in G2-M phase. The degree of DNA synthesis shutdown and the timing of the reinitiation of DNA synthesis and cell cycle progression were all fludarabine dose dependent. Interestingly, DNA synthesis reinitiated only at the G1-S boundary; cells in the S phase at the time of fludarabine administration appeared to disappear from the tumor population. To confirm these observations more directly, we pretreated tumor-bearing mice i.p. with chlorodeoxyuridine to mark the cells in the S phase, gave them fludarabine 0.5 h later, and then gave them iododeoxyuridine 0.5 h before tumor harvest. Flow cytometry analysis using antibodies specific for chlorodeoxyuridine- and iododeoxyuridined-labeled cells confirmed that cells in the S phase at the time of fludarabine administration never reinitiated DNA synthesis and disappeared from the tumor population. Immunohistological analysis of tumor sections obtained after fludarabine administration demonstrated that prelabeled S-phase cells took on an apoptotic appearance and gradually disappeared from the tumors. An in situ DNA end labeling assay demonstrated DNA fragmentation in these morphologically apoptotic cells. These results suggest that the mechanism of fludarabine enhancement of radiation response involves induced S-phase cell loss through an apoptotic pathway and subsequent synchronization of the remaining cells to a more radiosensitive cell cycle phase at the time of irradiation.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Experimentais/radioterapia , Tolerância a Radiação/efeitos dos fármacos , Vidarabina/análogos & derivados , Animais , Ciclo Celular/efeitos dos fármacos , DNA/biossíntese , Relação Dose-Resposta a Droga , Camundongos , Camundongos Endogâmicos C3H , Neoplasias Experimentais/patologia , Fase S/efeitos dos fármacos , Vidarabina/farmacologiaRESUMO
Recently, we demonstrated that an immunoglobulin-like cell adhesion molecule, C-CAM, acts as a tumor suppressor in prostate cancer. It is known that C-CAM is expressed in many epithelial cell types. In this study, we tested the possibility that C-CAM may also suppress bladder cancer progression. We used an orthotopic tumor model, which provides a relevant organ condition for examining the interaction between primary tumor cells and their microenvironment; this interaction has a critical impact on the behavior of carcinoma. We constructed a recombinant adenovirus expressing C-CAM1 (an isoform of C-CAM) and infected the 253J B-V cell line, a tumorigenic human bladder carcinoma subline. In vitro, C-CAM1 protein was detected in C-CAM1 adenovirus-infected cells but not in antisense control virus-infected cells, and the levels of expression showed dose dependency. When these cells were injected orthotopically in nude mice, we found that the increased expression of C-CAM1 in the 253J B-V cells repressed the growth of 253J B-V-induced tumors. Taken together, these data indicate that C-CAM1 is a potent tumor suppressor in human bladder cancer.
Assuntos
Adenosina Trifosfatases/fisiologia , Moléculas de Adesão Celular/fisiologia , Neoplasias da Bexiga Urinária/metabolismo , Neoplasias da Bexiga Urinária/patologia , Adenosina Trifosfatases/biossíntese , Adenoviridae/genética , Adenoviridae/metabolismo , Infecções por Adenoviridae/metabolismo , Animais , Antígenos CD , Antígeno Carcinoembrionário , Moléculas de Adesão Celular/biossíntese , Divisão Celular/fisiologia , Progressão da Doença , Feminino , Expressão Gênica , Vetores Genéticos , Glicoproteínas , Humanos , Recém-Nascido , Masculino , Camundongos , Camundongos Nus , Sensibilidade e Especificidade , Células Tumorais Cultivadas , Neoplasias da Bexiga Urinária/virologiaRESUMO
The Mildew resistance Locus O (MLO) family is unique to plants, containing genes that were initially identified as a susceptibility factor to powdery mildew pathogens. However, little is known about the roles and functional diversity of this family in rice, a model crop plant. The rice genome has 12 potential MLO family members. To achieve systematic functional assignments, we performed a phylogenomic analysis by integrating meta-expression data obtained from public sources of microarray data and real-time expression data into a phylogenic tree. Subsequently, we identified 12 MLO genes with various tissue-preferred patterns, including leaf, root, pollen, and ubiquitous expression. This suggested their functional diversity for morphological agronomic traits. We also used these integrated transcriptome data within a phylogenetic context to estimate the functional redundancy or specificity among OsMLO family members. Here, OsMLO12 showed preferential expression in mature pollen; OsMLO4, in the root tips; OsMLO10, throughout the roots except at the tips; and OsMLO8, expression preferential to the leaves and trinucleate pollen. Of particular interest to us was the diurnal expression of OsMLO1, OsMLO3, and OsMLO8, which indicated that they are potentially significant in responses to environmental changes. In osdxr mutants that show defects in the light response, OsMLO1, OsMLO3, OsMLO8, and four calmodulin genes were down-regulated. This finding provides insight into the novel functions of MLO proteins associated with the light-responsive methylerythritol 4-phosphate pathway. In addition, abiotic stress meta-expression data and real-time expression analysis implied that four and five MLO genes in rice are associated with responses to heat and cold stress, respectively. Upregulation of OsMLO3 by Magnaporthe oryzae infection further suggested that this gene participates in the response to pathogens. Our analysis has produced fundamental information that will enhance future studies of the diverse developmental or physiological phenomena mediated by the MLO family in this model plant system.
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The secondary structure of 5-S rRNAs of Thermus aquaticus (an extreme thermophile), Bacillus stearothermophilus (a moderate thermophile) and Escherichia coli (a mesophile) was compared using thermal denaturation techniques under varying ionic conditions. At a low ionic strength (10 mM K+), the Tm of T. aquaticus 5-S RNA differed by only 1 degrees C from that of E. coli RNA and the molecule was fully denatured well below the optimum growth temperature of the thermophile. The internal Na+, K+ and Mg2+ concentrations of T. aquaticus cells were determined to be 91 mM, 130 mM and 59 mM, respectively. Under these salt conditions, T. aquaticus 5-S RNA was significantly more stable than E. coli RNA and the 5-S RNA from B. stearothermophilus was intermediate as is its optimum growth temperature. The results suggest that the thermostability of macromolecules from thermophilic organisms may be specially dependent on the internal salt concentration. Furthermore, under these salt conditions, most of the secondary structure of the RNA remained stable at the optimum growth temperatures suggesting that ribosomal RNAs of thermophilic organisms contribute more to the thermostability of the ribosome than previously thought.
Assuntos
RNA Ribossômico , Sequência de Bases , Cátions Monovalentes , Estabilidade de Medicamentos , Escherichia coli , Geobacillus stearothermophilus , Peso Molecular , Conformação de Ácido Nucleico , Desnaturação de Ácido Nucleico , Concentração Osmolar , RNA Ribossômico/isolamento & purificação , Temperatura , ThermusRESUMO
Previous reports suggest that resistance to mitoxantrone in different tumor cell lines is unrelated to the overexpression of p-glycoprotein. In order to determine the role of p-glycoprotein in the cellular pharmacology of mitoxantrone flow cytometry and confocal microscopy were used to study two human myeloid leukemia cell lines selected for resistance to mitoxantrone (HL-60MX2) and doxorubicin (HL-60DOX). To optimize the detection of intracellular mitoxantrone, we determined the maximum excitation (607 nm) and emission (684 nm) wavelength by fluorescence spectroscopy. The modified flow cytometric conditions using 568.2 nm laser emission for excitation and a 620 nm long pass filter for fluorescence collection resulted in a 1-log increase in sensitivity, compared with standard 488-nm laser excitation. Uptake and retention of mitoxantrone in the presence of verapamil, a calcium channel blocker known to inhibit p-glycoprotein, were analyzed. Our results showed no change in uptake and retention of the drug in p-glycoprotein-negative mitoxantrone-resistant HL-60MX2 cells and in its sensitive parental line, HL-60s. In contrast, 3.1- and 2.4-fold increases were found in uptake and retention of mitoxantrone in p-glycoprotein-positive cells (HL-60DOX) incubated with verapamil. Confocal microscopy of intracellular drug distribution demonstrated reduced nuclear uptake, which could be reversed by verapamil, in HL-60DOX. A characteristic punctate pattern was observed for the intracytoplasmic drug distribution in HL-60DOX and HL-60MX2 cells and was partially modified by the presence of verapamil in HL-60DOX cells. Verapamil increased cytotoxicity of mitoxantrone two-fold in HL-60DOX cells, 1.4-fold in HL-60MX2, and had no effect in HL-60s. Our study demonstrates that the cellular pharmacology of mitoxantrone is affected by p-glycoprotein and can be reversed at least in part by verapamil. Other mechanisms of resistance however, seem to play a determinant role in the modulation of mitoxantrone cytotoxicity.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/análise , Antineoplásicos/farmacologia , Mitoxantrona/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Resistência a Múltiplos Medicamentos , Citometria de Fluxo , Células HL-60 , Humanos , Microscopia Confocal , Mitoxantrona/farmacocinética , Reação em Cadeia da Polimerase , Células Tumorais Cultivadas , Verapamil/farmacologiaRESUMO
Detection of karyotypic clonal abnormalities are prognostically useful in patients with acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS), but cytogenetic methods are not sensitive enough to detect low numbers of residual leukemic cells in patients who have achieved complete remission (CR). Fluorescence in situ hybridization (FISH) and fluorescence activated cell sorting (FACS) were used to investigate the frequency and presence of minimal residual disease (MRD) in AML and MDS patients (n = 28) with monosomy of chromosomes 7, 17 and 18 and trisomy of chromosomes 6, 8, 9 and 10 in CR. MRD was detected in all patients with monosomy 7 (n = 10) and followed by relapse in eight patients after 4.8 +/- 3.1 months. In contrast, persistent leukemic cells occurred in 11/12 patients with trisomy 8, but only three of them relapsed after 7.7 +/- 4.0 months. Cox regression analysis showed that cytogenetic class and levels of clonal cells at CR were related to time to relapse (P = 0.001). The level of MRD identified patients at high and low risk of relapse. High absolute levels of proliferating residual leukemic cells correlated with monosomy 7 and high risk of relapse.
Assuntos
Aberrações Cromossômicas , Células-Tronco Hematopoéticas/ultraestrutura , Leucemia Mieloide/patologia , Síndromes Mielodisplásicas/patologia , Células-Tronco Neoplásicas/ultraestrutura , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia Refratária com Excesso de Blastos/diagnóstico , Anemia Refratária com Excesso de Blastos/genética , Anemia Refratária com Excesso de Blastos/patologia , Antígenos de Diferenciação/análise , Antígenos de Neoplasias/análise , Divisão Celular , Cromossomos Humanos Par 7 , Células Clonais/química , Células Clonais/ultraestrutura , Progressão da Doença , Intervalo Livre de Doença , Feminino , Citometria de Fluxo , Células-Tronco Hematopoéticas/química , Humanos , Imunofenotipagem , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Mieloide/classificação , Leucemia Mieloide/diagnóstico , Leucemia Mieloide/genética , Tábuas de Vida , Masculino , Pessoa de Meia-Idade , Monossomia , Síndromes Mielodisplásicas/classificação , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/genética , Neoplasia Residual , Células-Tronco Neoplásicas/química , Modelos de Riscos Proporcionais , RecidivaRESUMO
This report describes the use of 21-, 16 alpha- and 11 alpha -[2'-3H]bromoacetoxyprogesterone as affinity labels to characterize the human uterine progesterone receptor (HPR). These three derivatives can bind to and displace progesterone bound to the HPR. This affinity labelling was inhibited by an excess of radioinert progesterone and could not be demonstrated if bovine serum albumin was used in place of the HPR. Bromoacetic acid alone did not affinity label the HPR. Polyacrylamide gel electrophoresis under denaturing conditions showed that all three derivatives bound to a 45,000 molecular weight protein.
Assuntos
Marcadores de Afinidade/metabolismo , Hidroxiprogesteronas/metabolismo , Receptores de Progesterona/metabolismo , Útero/metabolismo , Ligação Competitiva , Estabilidade de Medicamentos , Feminino , Humanos , Progesterona/metabolismoRESUMO
Neonatal administration of estradiol-17beta (E2-17beta) increases the nuclear DNA content in the mouse reproductive tract. Similar responses have been demonstrated for synthetic estrogens such as diethylstilbestrol. One of the questions raised regarding environmental estrogens such as organochlorines is whether they are potent enough to result in abnormal changes such as those demonstrated by both natural and synthetic estrogens. To test this hypothesis, female BALB/c mice were treated neonatally (days 1-5) with either E2-17beta or estradiol-17alpha (E2-17alpha), an inactive stereoisomer in adult reproductive tissues. We also proposed whether neonatal administration of (E2-17alpha) was tumorigenic and whether the effects were age dependent. To answer these questions, one set each of 10 day-old treated and control mice received short-term secondary administration of E2-17beta, E2-17alpha, or cholesterol. Cervicovaginal tracts from intact BALB/c mice were examined histologically and by flow cytometry at 70 days of age and by histology alone at 18 to 22 months of age. The results include several important findings: a) like E2-17beta, neonatal E2-17alpha treatment induced persistent vaginal cornification, hypospadias, vaginal concretions, and hyperproliferation in nearly 100% of the animals regardless of the secondary treatment for most groups; b) neonatal E2-17alpha treatment increased the nuclear DNA content of cervicovaginal epithelium at one-half both the level (mean DNA index of 1.02 vs 1.04) and incidence (22 vs 46% of the animals) of E2-17beta; c) short-term secondary treatment with E2-17alpha, unlike E2-17beta, did not significantly augment the increase in DNA content (13% for E2-17alpha vs 37 and 56% for control and E2-17beta, respectively); and d) neonatal administration with E2-17alpha induced adenosquamous tumors in the reproductive tract in 25% of the animals. Therefore, the biological effects (estrogenic potency) of E2-17alpha may be age dependent.