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1.
Childs Nerv Syst ; 37(1): 81-89, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32504172

RESUMEN

PURPOSE: Modern pediatric neurosurgery succeeded in reducing ventricle-peritoneal shunt malfunctions and shunt revisions. However, some children may be submitted to many surgeries, posing burden to their caregivers. And most of caregiver assume responsibility for care without emotional preparation. It is up to health professionals to carry out the educational process. The aim of this study was to evaluate the knowledge, attitude, and practice of informal caregivers of children with hydrocephalus before and after intervention with previously developed educational material. METHODS: This is a quasi-experimental, before-and-after study conducted with 32 informal caregivers of children with hydrocephalus. Data collection occurred in three stages: pre-test, educational intervention through educational material, and post-test. The knowledge, attitude, and practice survey was used as a pre-test and post-test assessment tool. RESULTS: The mean score in the three domains (knowledge, attitude, and practice) was lower in the pre-test compared to the post-test. After caregivers read the educational material, the correct answer rate increased by 17% in the knowledge domain and 21.4% in the practice domain, with p values of < 0.01. In the attitude domain, there was a non-significant increase of 0.06 (2.0%, p = 0.161) points in the mean score between the pre-test and the post-test. CONCLUSION: The educational material enables the acquisition of knowledge of informal caregivers of children with hydrocephalus. This can be used by health professionals to strengthen the bond between professional care staff and family, and to facilitate the educational process.


Asunto(s)
Cuidadores , Hidrocefalia , Niño , Personal de Salud , Humanos , Hidrocefalia/cirugía , Encuestas y Cuestionarios
2.
Rep Pract Oncol Radiother ; 24(6): 585-592, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31660051

RESUMEN

AIM: To evaluate if a radiochromic film (RF) Gafchromic EBT3 is suitable for surface dose measurements of radiotherapy treatments performed with a 6 MV linear accelerator. Two aspects of RF were analyzed, beam energy dependence and surface dose determination. BACKGROUND: The measurements done at the surface or near the radiation source are done without charged electronic equilibrium and also have contribution of electron contamination. The detectors used for these measurements should not alter the dose to the target. To counteract these dosimetric problems it is proposed to do the measurements with radiochromic films which are thin detectors and have tissue equivalent properties. MATERIALS AND METHODS: The measurements were done using a Novalis linear accelerator (LINAC) with nominal energy of 6 MV. To determine the surface dose, the total scatter factors (TSF) of three different field sizes were measured in a water phantom at 5 cm depth. Energy dependence of EBT3 was studied at three different depths, using a solid water phantom. The surface measurements were done with the RF for the same field sizes of the TSF measurements. The value of the percentage depth dose was calculated normalizing the doses measured in the RF with the LINAC output, at 5 cm depth, and the TSF. RESULTS: The radiochromic films showed almost energy independence, the differences between the curves are 1.7% and 1.8% for the 1.5 cm and 10 cm depth, respectively. The percentage depth doses values at the surface measured for the 10 cm × 10 cm, 5 cm × 5 cm and 1 cm × 1 cm were 26.1 ± 1.3%, 21.3 ± 2.4% and 20.2 ± 2.6%, respectively. CONCLUSIONS: The RF-EBT3 seems to be a detector suitable for measurements of the dose at the surface. This suggests that RF-EBT3 films might be good candidates as detectors for in vivo dosimetry.

3.
Climacteric ; 21(5): 462-466, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-29635954

RESUMEN

BACKGROUND: Although aging is considered a risk factor for pelvic floor muscle dysfunction (PFMD), the effect of aging on the function of the pelvic floor muscles (PFM) remains unclear. OBJECTIVE: To compare PFM function and activity in nulliparous women in different age groups. METHODS: This was a cross-sectional study in which 70 women with ages between 18 and 69 years were divided into five age groups for evaluation. Initially, medical histories were taken, and then the PFM function was assessed using digital palpation (Modified Oxford Scale), manometry and surface electromyography (sEMG). The Kruskal-Wallis test was applied to check the differences between the groups. The Spearman correlation coefficient was used to verify the correlations between age and PFM function, manometry values and sEMG. A significance level of 5% was adopted. RESULTS: No significant differences were observed between the different age groups in PFM digital palpation, manometry values and sEMG. There was a low negative correlation between age root mean square and peak of sEMG signals. CONCLUSION: This study found no difference in PFM function and activity between nulliparous women in the five different age groups. Future long-term large prospective studies are required to confirm these findings.


Asunto(s)
Factores de Edad , Electromiografía , Músculo Esquelético/fisiología , Diafragma Pélvico/fisiología , Adolescente , Adulto , Anciano , Estudios Transversales , Femenino , Humanos , Manometría , Persona de Mediana Edad , Palpación , Paridad , Trastornos del Suelo Pélvico , Adulto Joven
4.
Genet Mol Res ; 16(3)2017 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-28829891

RESUMEN

With the imminence of global climate changes that affect the temperature and the rainfall uniformity, it is growing the concern about the adaptation of crops to the water deficit. Thus, the objective of this study was to evaluate alterations in physiological and enzymatic mechanisms during the germination process of sesame seeds under different water availability. To simulate the water restriction we used PEG6000, a high molecular weight molecule that does not penetrate the seed structure but allows different osmotic potentials. The treatments were -0.1, -0.2, and -0.3 MPa, and the control. Germination, first-count germination, germination velocity index, and length and dry mass of the hypocotyl and radicle were performed. The seeds were weighed before and after treatments every 3 h. After each weighing, 100 seeds were taken for analysis of the enzymes alcohol dehydrogenase (ADH), malate dehydrogenase, esterase, catalase (CAT), superoxide dismutase (SOD), isocitrate lyase (ICL), and glutamate dehydrogenase (GTDH). The statistical design was completely randomized with five replications. PEG6000 prolonged ADH activity during the beginning of germination, maintaining the anaerobic metabolism for longer. Subsequently, their activity was reduced, as well as ICL, favoring the deterioration of the seeds that take the time to germinate. Behavior was evidenced by the appearance of SOD, CAT, and GTDH isoforms after 24 h of imbibition when water restriction was imposed. Therefore, the PEG600 is efficient in simulating water deficit conditions in future scenarios of climate change, offering impotent information regarding the germination behavior of the plants under these conditions.


Asunto(s)
Presión Osmótica , Semillas/enzimología , Sesamum/enzimología , Alcohol Deshidrogenasa/metabolismo , Catalasa/metabolismo , Esterasas/metabolismo , Germinación , Glutamato Deshidrogenasa/metabolismo , Isocitratoliasa/metabolismo , Malato Deshidrogenasa/metabolismo , Proteínas de Plantas/metabolismo , Semillas/crecimiento & desarrollo , Semillas/metabolismo , Sesamum/crecimiento & desarrollo , Sesamum/metabolismo , Superóxido Dismutasa/metabolismo
5.
Cryo Letters ; 38(4): 257-262, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29734426

RESUMEN

BACKGROUND: That cryopreservation can induce alterations in sperm. OBJECTIVE: The goal of this study was to evaluate sperm quality and distribution of N-acetylglucosamine, sialic acid and mannose residues in sperm cryopreserved of red-tailed hawk (Buteo jamaicensis). MATERIALS AND METHODS: We studied twenty samples of ejaculated semen for each cryoprotectant dimethylsulfoxide or polyvinylpyrrolidone. Carbohydrate identification was carried out with lectins Triticum vulgaris agglutinin to N-acetylglucosamine and sialic acid and Concanavalia ensiformis for mannose residues. Sperm viability was not altered but motility decreased significantly with both crioprotectants compared with fresh sperm. RESULTS: Neither the number of WGA positive sperm nor the distribution of N-acetylglucosamine and/or sialic acid residues were affected by the cryopreservation procedure. The sperm proportion with fluorescence associated with the presence of mannose residues was higher in thawed sperm. CONCLUSION: Values obtained with the cryopreservation technique proposed in this study by freezing drops in liquid nitrogen, were within normal parameters established for good quality fresh semen. We can say that it can be used for assisted reproduction of Buteo jamaicensis.


Asunto(s)
Carbohidratos/química , Criopreservación/métodos , Crioprotectores/farmacología , Dimetilsulfóxido/farmacología , Halcones/fisiología , Povidona/farmacología , Preservación de Semen/métodos , Espermatozoides/efectos de los fármacos , Animales , Masculino , Membranas , Semen/efectos de los fármacos , Motilidad Espermática/efectos de los fármacos , Coloración y Etiquetado , Aglutininas del Germen de Trigo/metabolismo
7.
J Nanosci Nanotechnol ; 13(7): 4694-702, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23901492

RESUMEN

Biomaterials nanofibrous electrospun with biodegradable polymers have the advantage of the similarity to natural extracellular matrices, showing promising as scaffolds for application in tissue engineering. Sedum dendroideum is a phytotherapic drug that stands out for its healing properties and anti-inflammatory. This study presents the efficacy of PLA electrospun membranes used as support S. dendroideum extract releasing on excisional skin lesions of Wistar rats. The PLA porous membranes, which are nonwoven fibrous mats, were obtained by electrospinning using a conventional apparatus with a flat collector. The animals were randomly divided into nine groups: control (C), animals treated with electrospun membranes of PLA (M), animals treated with extract of S. dendroideum dissolved in saline (F), animals treated with membranes of PLA with 10% S. dendroideum (MF10), animals treated with membranes of PLA with 25% S. dendroideum (MF25). Tissue samples were taken after 2, 6 and 10 days after surgery and were subjected to structural analysis and morphology. The experimental observations showed the application of the phytotherapic incorporated in the membrane promoted a significant response regarding the number of inflammatory cells, percentage of mature collagen fibers and epithelium birrefringent in thickness excisional skin lesions in Wistar rats. It was also demonstrated that the application of the PLA membranes without the extract promoted similar responses tissues.


Asunto(s)
Vendajes , Ácido Láctico/química , Nanocápsulas/administración & dosificación , Extractos Vegetales/administración & dosificación , Polímeros/química , Sedum/química , Andamios del Tejido , Heridas Penetrantes/terapia , Animales , Electroquímica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Masculino , Ensayo de Materiales , Nanocápsulas/química , Extractos Vegetales/química , Poliésteres , Ratas , Ratas Wistar , Cicatrización de Heridas/efectos de los fármacos , Heridas Penetrantes/patología
8.
Phys Rev Lett ; 106(1): 015501, 2011 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-21231752

RESUMEN

We present optical conductivity studies of the type-I clathrate Ba8Ga16Sn30, using a terahertz time-domain spectrometer (0.3-3.0 THz). The lowest-lying spectral peak at 0.72 THz due to the Ba(2) ion's off-center vibration in the oversized cage shows a drastic and anomalous temperature dependence. Below about 100 K, the single broad peak splits into two subpeaks, and with further lowering of the temperature, the spectral shape of this so-called rattling phonon shows non-Boltzmann broadening to the point that the linewidth becomes comparable to the peak frequency. Whereas the initial splitting can be understood by assuming a multiwell anharmonic potential, the strong linewidth broadening toward low temperature cannot, since the Boltzmann factor generally sharpens the low-temperature spectra. The observed behavior suggests strong interaction between the local anharmonic phonons and other excitations.

9.
Biochim Biophys Acta Mol Basis Dis ; 1866(11): 165895, 2020 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-32681864

RESUMEN

S-adenosyl-L-methionine is an endogenous molecule with hepato-protective properties linked to redox regulation and methylation. Here, the potential therapeutic value of SAMe was tested in 17 patients with PBC, a cholestatic disease with autoimmune phenomena targeting small bile ducts. Nine patients responded to SAMe (SAMe responders) with increased serum protein S-glutathionylation. That posttranslational protein modification was associated with reduction of serum anti-mitochondrial autoantibodies (AMA-M2) titers and improvement of liver biochemistry. Clinically, SAMe responders were younger at diagnosis, had longer duration of the disease and lower level of serum S-glutathionylated proteins at entry. SAMe treatment was associated with negative correlation between protein S-glutathionylation and TNFα. Furthermore, AMA-M2 titers correlated positively with INFγ and FGF-19 while negatively with TGFß. Additionally, cirrhotic PBC livers showed reduced levels of glutathionylated proteins, glutaredoxine-1 (Grx-1) and GSH synthase (GS). The effect of SAMe was also analyzed in vitro. In human cholangiocytes overexpressing miR-506, which induces PBC-like features, SAMe increased total protein S-glutathionylation and the level of γ-glutamylcysteine ligase (GCLC), whereas reduced Grx-1 level. Moreover, SAMe protected primary human cholangiocytes against mitochondrial oxidative stress induced by tBHQ (tert-Butylhydroquinone) via raising the level of Nrf2 and HO-1. Finally, SAMe reduced apoptosis (cleaved-caspase3) and PDC-E2 (antigen responsible of the AMA-M2) induced experimentally by glycochenodeoxycholic acid (GCDC). These data suggest that SAMe may inhibit autoimmune events in patients with PBC via its antioxidant and S-glutathionylation properties. These findings provide new insights into the molecular events promoting progression of PBC and suggest potential therapeutic application of SAMe in PBC.


Asunto(s)
Autoinmunidad/efectos de los fármacos , Colangitis/tratamiento farmacológico , Colangitis/fisiopatología , S-Adenosilmetionina/farmacología , S-Adenosilmetionina/uso terapéutico , Antioxidantes/metabolismo , Células Cultivadas , Colangitis/inmunología , Colestasis/tratamiento farmacológico , Colestasis/metabolismo , Ensayo de Inmunoadsorción Enzimática , Femenino , Glutatión/análogos & derivados , Glutatión/metabolismo , Humanos , Immunoblotting , Inmunohistoquímica , Masculino , Persona de Mediana Edad
10.
Cell Mol Biol (Noisy-le-grand) ; 55(1): 29-37, 2009 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-19267999

RESUMEN

Activation of the epidermal growth factor receptor (EGFR) plays an important role in liver regeneration and resistance to acute injury. However its chronic activation participates in the progression of liver disease, including fibrogenesis and malignant transformation. Hepatobiliary disease represents a constant feature in the clinically relevant Fechm1pas/Fechm1pas genetic model of erythropoietic protoporphyria (EPP). Similarly, chronic administration of griseofulvin to mice induces pathological changes similar to those found in patients with EPP-associated liver injury. We investigated the hepatic expression of the EGFR and its seven most relevant ligands in Fechm1pas/Fechm1pas mice bred in three different backgrounds, and in griseofulvin-induced protoporphyria. We observed that the expression of amphiregulin, betacellulin and epiregulin was significantly increased in young EPP mice when compared to aged-matched controls in all genetic backgrounds. The expression of these ligands was also tested in older (11 months) BALB/cJ EPP mice, and it was found to remain induced, while that of the EGFR was downregulated. Griseofulvin feeding also increased the expression of amphiregulin, betacellulin and epiregulin. Interestingly, protoporphyrin accumulation in cultured hepatic AML-12 cells readily elicited the expression of these three EGFR ligands. Our findings suggest that protoporphyrin could directly induce the hepatic expression of EGFR ligands, and that their chronic upregulation might participate in the pathogenesis of EPP-associated liver disease.


Asunto(s)
Receptores ErbB/agonistas , Receptores ErbB/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Protoporfiria Eritropoyética/metabolismo , Anfirregulina , Animales , Betacelulina , Línea Celular , Familia de Proteínas EGF , Factor de Crecimiento Epidérmico/genética , Epigen , Epirregulina , Glicoproteínas/genética , Griseofulvina/farmacología , Factor de Crecimiento Similar a EGF de Unión a Heparina , Péptidos y Proteínas de Señalización Intercelular/genética , Hepatopatías/genética , Hepatopatías/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Protoporfiria Eritropoyética/genética , Protoporfirinas/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Crecimiento Transformador alfa/genética
11.
J Nanosci Nanotechnol ; 9(6): 3883-90, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19504936

RESUMEN

Nanocomposites of recycled poly(ethylene terephthalate) (rPET) containing 2.5 wt% and 5.0 wt% of montmorillonite modified with organophilic quaternary ammonium salt (DELLITE 67G) were prepared by melt compounding using a co-rotating twin-screw type extruder with two organoclay contents were used: 2.5 wt% and 5.0 wt% and were prepared using two different rotation speeds: 150 and 250 rpm. Thermal characterization (analysis) of the nanocomposites was performed using differential scanning calorimetry (DSC) analysis. The results from DSC measurements showed that the addition of organoclay affects recycled PET's crystallization for two screw rotation speeds studies. The nucleating effect of organoclay was investigated. Morphological analysis using Transmission Electron Microscopy (TEM) revealed the presence of fully exfoliated clay platelets in samples prepared at 150 rpm.

12.
Dent Mater ; 35(12): 1740-1749, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31543375

RESUMEN

BACKGROUND: Bioengineering aims to develop innovative scaffolds to improve cellular activities for tissue regeneration. OBJECTIVES: To evaluate the biological behavior of human dental pulp stem cells (hDPSCs) seeded onto an experimental polymeric-based scaffold comprising poly-ε-caprolactone/poly (rotaxane). MATERIAL AND METHODS: Adhesion, viability, and proliferation as well as alkaline phosphatase (ALP) activity, mineralized nodule formation (alizarin red assay), and expression of genes related to osteogenic differentiation, including ALP, type 1 collagen alpha 1 (COL1A1), Runt-related transcription factor (Runx-2), and osteocalcin (BGLAP/OCN), were evaluated in hDPSCs seeded onto polymeric scaffolds. RESULTS: hDPSCs expressed typical levels of mesenchymal stem cell surface markers. Cell growth increased upon cultivation on polymeric blend scaffold and the cells gained osteoblast-like appearance. Fourteen days after seeding hDPSCs on the scaffolds, irrespective to the culture medium used (clonogenic or mineralization medium), the cells presented ALP activity higher than that of control cells grown in clonogenic medium. The cells cultivated in mineralization medium on the scaffold showed significantly higher expression of all genes than the control cells, except for BGLAP gene expression. At 21 days, the group cultivated on the scaffold and mineralization medium showed maximum level of mineralization. SIGNIFICANCE: Poly-ε-caprolactone/poly (rotaxane) blend is noncytotoxic to hDPSCs and improved genomic and functional osteogenic differentiation. Thus, poly-ε-caprolactone/poly (rotaxane) blend may serve as a promising bioactive biomaterial for bone tissue bioengineering.


Asunto(s)
Osteogénesis , Rotaxanos , Caproatos , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Pulpa Dental , Humanos , Lactonas , Poliésteres , Ingeniería de Tejidos , Andamios del Tejido
13.
Oncogene ; 25(27): 3866-84, 2006 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-16799628

RESUMEN

Hepatocellular carcinoma (HCC), one of the most common cancers worldwide, is often diagnosed at an advanced stage when most potentially curative therapies such as resection, transplantation or percutaneous and transarterial interventions are of limited efficacy. The fact that HCC is resistant to conventional chemotherapy, and is rarely amenable to radiotherapy, leaves this disease with no effective therapeutic options and a very poor prognosis. Therefore, the development of more effective therapeutic tools and strategies is much needed. HCCs are phenotypically and genetically heterogeneous tumors that commonly emerge on a background of chronic liver disease. However, in spite of this heterogeneity recent insights into the biology of HCC suggest that certain signaling pathways and molecular alterations are likely to play essential roles in HCC development by promoting cell growth and survival. The identification of such mechanisms may open new avenues for the prevention and treatment of HCC through the development of targeted therapies. In this review we will describe the new potential therapeutic targets and clinical developments that have emerged from progress in the knowledge of HCC biology, In addition, recent advances in gene therapy and combined cell and gene therapy, together with new radiotherapy techniques and immunotherapy in patients with HCC will be discussed.


Asunto(s)
Carcinoma Hepatocelular/terapia , Neoplasias Hepáticas/terapia , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/radioterapia , Carcinoma Hepatocelular/virología , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/virología
14.
Cancer Lett ; 254(1): 30-41, 2007 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-17321672

RESUMEN

Amphiregulin (AR) is a member of the epidermal growth factor family and a ligand of the epidermal growth factor receptor (EGFR). As other ligands of the EGFR, AR is synthesized as a precursor that is shed from the plasma membrane by metalloproteases. Hyperactive autocrine loops involving AR production have been described in a variety of tumors, and this growth factor is thought to play a non-redundant role in cancer development. AR expression is not detected in the normal liver, however it is readily induced during acute liver injury and behaves as a potent pro-regenerative and survival factor. Increased AR expression is also detected in human chronic liver injury (liver cirrhosis), which is considered a pre-neoplastic condition. Recent evidences suggest that AR can play a unique role in liver tumorigenesis and in the maintenance of the neoplastic phenotype of hepatocarcinoma cells. In this review, we summarize some aspects of AR patho-biology and the rationale behind its definition as a novel target in hepatocarcinoma therapy.


Asunto(s)
Carcinoma Hepatocelular/patología , Glicoproteínas/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Neoplasias Hepáticas/patología , Anfirregulina , Carcinoma Hepatocelular/metabolismo , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Progresión de la Enfermedad , Familia de Proteínas EGF , Humanos , Hígado/metabolismo , Hígado/patología , Neoplasias Hepáticas/metabolismo , Modelos Biológicos , Transducción de Señal
16.
Cancer Res ; 54(9): 2424-8, 1994 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-8162591

RESUMEN

The effects of the bioflavonoid quercetin (3,3',4',5,7-pentahydroxyflavone) on the growth and cell cycle progression of the human breast cancer cell line MDA-MB468 have been studied. Quercetin inhibited cell proliferation with an IC50 (a drug concentration which inhibited growth by 50% following a 3-day exposure) value of 7 micrograms/ml. In actively growing cultures, the addition of quercetin resulted in the accumulation of cells at the G2-M phase. We have correlated these effects on cell proliferation with the observation that quercetin strongly inhibited, in a time- and dose-dependent fashion, the expression of the mutated p53 protein, which is the only form present at high levels in this cell line. This inhibition takes place at the translational level. Quercetin did not affect the steady-state mRNA levels of p53, but prevented the accumulation of newly synthesized p53 protein. This quercetin action appeared to be somewhat specific for p53 because the drug did not alter the amount of other proteins present in MDA-MB468 cells such as P-glycoprotein and did not prevent the induction of the synthesis of epidermal growth factor receptor in response to epidermal growth factor.


Asunto(s)
Neoplasias de la Mama/metabolismo , Quercetina/farmacología , Proteína p53 Supresora de Tumor/metabolismo , Neoplasias de la Mama/patología , Ciclo Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo/efectos de los fármacos , Femenino , Humanos , Mutación , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/genética
17.
Cancer Res ; 53(19): 4474-6, 1993 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-8402616

RESUMEN

Early responses of mammalian cells to ionizing radiation include the activation of a protein kinase C implicated in the regulation of gene expression, the stimulation of tyrosine kinase activities, and the enhancement of phosphatidylinositol turnover. In the present report we show that clinically relevant doses of gamma-radiation (2 Gy) stimulate phosphatidylcholine hydrolysis in human squamous carcinoma cells. Radiation induced the accumulation of intracellular [3H]choline and the simultaneous increase in [3H]myristoyl-phosphatidic acid, followed by a small increase in the levels of [3H]myristoyl-diacylglycerol. Furthermore, in the presence of ethanol, gamma-radiation stimulated the appearance of [32P]phosphatidylethanol, an indicator of phospholipase D transphosphatidylation activity. These data demonstrate for the first time that phospholipase D activation participates in signaling pathways in response to gamma-radiation.


Asunto(s)
Glicerofosfolípidos , Fosfolipasa D/metabolismo , Transducción de Señal/efectos de la radiación , Carcinoma de Células Escamosas , Colina/metabolismo , Activación Enzimática , Rayos gamma , Glicerilfosforilcolina/metabolismo , Neoplasias de Cabeza y Cuello , Humanos , Cinética , Ácido Mirístico , Ácidos Mirísticos/metabolismo , Ácidos Fosfatidicos/metabolismo , Fosfatidilcolinas/metabolismo , Fosfolipasa D/efectos de la radiación , Fosforilcolina/metabolismo , Células Tumorales Cultivadas
18.
J Phys Condens Matter ; 28(37): 375601, 2016 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-27419654

RESUMEN

The tuning of the electronic properties of heavy fermion compounds by chemical substitution provides excellent opportunities for further understanding the physics of hybridized ions in crystal lattices. Here we present an investigation on the effects of Cd doping in flux-grown single crystals of the complex intermetallic cage compound YbFe2Zn20, which has been described as a heavy fermion with a Sommerfeld coefficient of 535 mJ mol(-1) · K(-2). The substitution of Cd for Zn disturbs the system by expanding the unit cell and, in this case, the size of the Zn cages that surround the Yb and Fe. With an increasing amount of Cd, the hybridization between the Yb 4f electrons and the conduction electrons is weakened, as shown by a decrease in the Sommerfeld coefficient, which should be accompanied by a valence shift of the Yb(3+) due to the negative chemical pressure effect. This scenario is also supported by the low temperature DC magnetic susceptibility, which is gradually suppressed and shows an increment of the Kondo temperature, based on a shift to higher temperatures of the characteristic broad susceptibility peak. Furthermore, the DC resistivity decreases with the isoelectronic substitution of Cd for Zn, contrary to expectations in an increasingly disordered system, and implying that the valence shift is not related to charge carrier doping. The combined results demonstrate the excellent complementarity between positive physical pressure and negative chemical pressure, and point to a rich playground for exploring the physics and chemistry of strongly correlated electron systems in the general family of Zn20 compounds, despite their structural complexity.

19.
Oncogene ; 35(36): 4719-29, 2016 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-26804174

RESUMEN

Resisting death is a central hallmark of cancer cells. Tumors rely on a number of genetic mechanisms to avoid apoptosis, and alterations in mRNA alternative splicing are increasingly recognized to have a role in tumorigenesis. In this study, we identify the splicing regulator SLU7 as an essential factor for the preservation of hepatocellular carcinoma (HCC) cells viability. Compared with hepatocytes, SLU7 expression is reduced in HCC cells; however, further SLU7 depletion triggered autophagy-related cellular apoptosis in association with the overproduction of reactive oxygen species. Remarkably, these responses were not observed in primary human hepatocytes or in the well-differentiated HepaRG cell line. Mechanistically, we demonstrate that SLU7 binds the C13orf25 primary transcript in which the polycistronic oncomir miR-17-92 cluster is encompassed, and is necessary for its processing and expression. SLU7 knockdown altered the splicing of the C13orf25 primary transcript, and markedly reduced the expression of its miR-17, miR-20 and miR-92a constituents. This led to the upregulation of CDKN1A (P21) and BCL2L11 (BIM) expression, two bona fide targets of the miR-17-92 cluster and recognized mediators of its pro-survival and tumorigenic activity. Interestingly, altered splicing of miR-17-92 and downregulation of miR-17 and miR-20 were not observed upon SLU7 knockdown in non-transformed hepatocytes, but was found in other (HeLa, H358) but not in all (Caco2) non-hepatic tumor cells. The functional relevance of miR-17-92 dysregulation upon SLU7 knockdown was established when oxidative stress, autophagy and apoptosis were reversed by co-transfection of HCC cells with a miR-17 mimic. Together, these findings indicate that SLU7 is co-opted by HCC cells and other tumor cell types to maintain survival, and identify this splicing regulator as a new determinant for the expression of the oncogenic miR-17-92 cluster. This novel mechanism may be exploited for the development of antitumoral strategies in cancers displaying such SLU7-miR-17-92 crosstalk.


Asunto(s)
Empalme Alternativo/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , MicroARNs/genética , Factores de Empalme de ARN/genética , Apoptosis/genética , Autofagia/genética , Células CACO-2 , Carcinogénesis/genética , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Supervivencia Celular/genética , Regulación Neoplásica de la Expresión Génica , Células Hep G2 , Hepatocitos/metabolismo , Hepatocitos/patología , Humanos , Neoplasias Hepáticas/patología , ARN Largo no Codificante
20.
Oncogene ; 18(3): 689-701, 1999 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-9989819

RESUMEN

Cph was isolated from neoplastic Syrian hamster embryo fibroblasts initiated by 3-methylcholanthrene (MCA), and was shown to be a single copy gene in the hamster genome, conserved from yeast to human cells, expressed in fetal cells and most adult tissues, and acting synergistically with H-ras in the transformation of murine NIH3T3 fibroblasts. We have now isolated Syrian hamster full-length cDNAs for the cph oncogene and proto-oncogene. Nucleotide sequence analysis revealed that cph was activated in MCA-treated cells by a point-mutational deletion at codon 214, which caused a shift in the normal open reading frame (ORF) and brought a translation termination codon 33 amino acids downstream. While proto-cph encodes a protein (pcph) of 469 amino acids, cph encodes a truncated protein (cph) of 246 amino acids with a new, hydrophobic C-terminus. Similar mechanisms activated cph in other MCA-treated Syrian hamster cells. The cph and proto-cph proteins have partial sequence homology with two protein families: GDP/GTP exchange factors and nucleotide phosphohydrolases. In vitro translated, gel-purified cph proteins did not catalyze nucleotide exchange for H-ras, but were able to bind nucleotide phosphates, in particular ribonucleotide diphosphates such as UDP and GDP. Steady-state levels of cph mRNA increased 6.7-fold in hamster neoplastic cells, relative to a 2.2-fold increase in normal cells, when they were subjected to a nutritional stress such as serum deprivation. Moreover, cph-transformed NIH3T3 cells showed increased survival to various forms of stress (serum starvation, hyperthermia, ionizing radiation), strongly suggesting that cph participates in cellular mechanisms of response to stress.


Asunto(s)
Proteínas Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Células 3T3 , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Catálisis , Línea Celular , Supervivencia Celular , Transformación Celular Neoplásica , Clonación Molecular , Cricetinae , ADN Complementario , Regulación Neoplásica de la Expresión Génica , Factores de Intercambio de Guanina Nucleótido , Guanosina Difosfato , Guanosina Trifosfato , Mesocricetus , Ratones , Datos de Secuencia Molecular , Nucleótidos/metabolismo , Proteína Oncogénica p21(ras)/metabolismo , Proteínas Oncogénicas/genética , Oncogenes , Mutación Puntual , Proteínas/genética , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas/genética , Proto-Oncogenes , Homología de Secuencia de Aminoácido , Factores de Intercambio de Guanina Nucleótido ras
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