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1.
Ultrasound Obstet Gynecol ; 53(3): 367-375, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30014562

RESUMEN

OBJECTIVES: The soluble fms-like tyrosine kinase-1 (sFlt-1) to placental growth factor (PlGF) ratio is generally elevated some time before and at the clinical onset of pre-eclampsia. The PROGNOSIS study validated a sFlt-1/PlGF ratio cut-off of ≤ 38 to rule out the onset of pre-eclampsia within 1 week of testing in women with suspected disease. The aim of this study was to assess the predictive value of the sFlt-1/PlGF ratio to rule out the onset of pre-eclampsia for up to 4 weeks, and to assess the value of repeat measurements. METHODS: This was an exploratory post-hoc analysis of data from the PROGNOSIS study performed in pregnant women aged ≥ 18 years with suspected pre-eclampsia, who were at 24 + 0 to 36 + 6 weeks' gestation at their first clinic visit. Serum samples were collected at the first visit and weekly thereafter. sFlt-1 and PlGF levels were measured using Elecsys® sFlt-1 and PlGF immunoassays. Whether the sFlt-1/PlGF ratio cut-off of ≤ 38 used to rule out the onset of pre-eclampsia within 1 week could predict the absence of pre-eclampsia 2, 3, and 4 weeks post-baseline was assessed. The value of repeat sFlt-1/PlGF testing was assessed by examining the difference in sFlt-1/PlGF ratio 2 and 3 weeks after the first measurement in women with, and those without, pre-eclampsia or adverse fetal outcome. RESULTS: On analysis of 550 women, sFlt-1/PlGF ratio ≤ 38 ruled out the onset of pre-eclampsia 2 and 3 weeks post-baseline with high negative predictive values (NPV) of 97.9% and 95.7%, respectively. The onset of pre-eclampsia within 4 weeks was ruled out with a high NPV (94.3%) and high sensitivity and specificity (66.2% and 83.1%, respectively). Compared with women who did not develop pre-eclampsia, those who developed pre-eclampsia had significantly larger median increases in sFlt-1/PlGF ratio at 2 weeks (∆, 31.22 vs 1.45; P < 0.001) and at 3 weeks (∆, 48.97 vs 2.39; P < 0.001) after their initial visit. Women who developed pre-eclampsia and/or adverse fetal outcome compared with those who did not had a significantly greater median increase in sFlt-1/PlGF ratio over the same period (∆, 21.22 vs 1.40; P < 0.001 at 2 weeks; ∆, 34.95 vs 2.30; P < 0.001 at 3 weeks). CONCLUSION: The Elecsys® immunoassay sFlt-1/PlGF ratio can help to rule out the onset of pre-eclampsia for 4 weeks in women with suspected pre-eclampsia. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.


Asunto(s)
Factor de Crecimiento Placentario/sangre , Preeclampsia/diagnóstico , Diagnóstico Prenatal/métodos , Receptor 1 de Factores de Crecimiento Endotelial Vascular/sangre , Adulto , Biomarcadores/metabolismo , Femenino , Feto , Edad Gestacional , Humanos , Preeclampsia/sangre , Preeclampsia/epidemiología , Preeclampsia/mortalidad , Valor Predictivo de las Pruebas , Embarazo , Pronóstico , Estudios Prospectivos , Estudios Retrospectivos
2.
Phys Rev Lett ; 110(4): 048103, 2013 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-25166204

RESUMEN

We develop a generic description of thin active films that captures key features of flow and rotation patterns emerging from the activity of chiral motors which introduce torque dipoles. We highlight the role of the spin rotation field and show that fluid flows can occur in two ways: by coupling of the spin rotation rate to the velocity field via a surface or by spatial gradients of the spin rotation rate. We discuss our results in the context of patches of bacteria on solid surfaces and groups of rotating cilia. Our theory could apply to active chiral processes in the cell cytoskeleton and in epithelia.


Asunto(s)
Modelos Biológicos , Modelos Químicos , Actinas/química , Actinas/fisiología , Adhesión Bacteriana/fisiología , Cilios/química , Cilios/fisiología , Citoesqueleto/química , Citoesqueleto/fisiología , Miosinas/química , Miosinas/fisiología , Torque
3.
Eur Phys J E Soft Matter ; 35(9): 89, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23001784

RESUMEN

Active processes in biological systems often exhibit chiral asymmetries. Examples are the chirality of cytoskeletal filaments which interact with motor proteins, the chirality of the beat of cilia and flagella as well as the helical trajectories of many biological microswimmers. Here, we derive constitutive material equations for active fluids which account for the effects of active chiral processes. We identify active contributions to the antisymmetric part of the stress as well as active angular momentum fluxes. We discuss four types of elementary chiral motors and their effects on a surrounding fluid. We show that large-scale chiral flows can result from the collective behavior of such motors even in cases where isolated motors do not create a hydrodynamic far field.


Asunto(s)
Hidrodinámica , Modelos Moleculares , Citoesqueleto de Actina/química , Citoesqueleto de Actina/metabolismo , Cinética , Conformación Molecular , Torque
4.
Sci Rep ; 12(1): 2907, 2022 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-35190584

RESUMEN

Physical activity (PA) helps prevention and aftercare of sporadic breast cancer (BC), cardiopulmonary fitness (CPF) being an age-independent predictor of tumor-specific mortality. Therefore, we wanted to identify predictors of CPF (represented by peak oxygen uptake: VO2peak) in BRCA1/2 mutation carriers whose risk of developing BC is high. We used cross-sectional data from 68 BRCA1/2 germline mutation carrying women participating in the randomized, prospective, controlled clinical study LIBRE-1. Assessments included cardiopulmonary exercise testing, medical and lifestyle history plus socioeconomic status. Additionally, the participants completed a psychological questionnaire regarding their attitude, subjective norms, perceived behavior control and intention towards PA. A multivariate logistic regression model was used to identify predictors for participants reaching their age- and sex-adjusted VO2peak reference values. 22 participants (median age: 40 years, interquartile range (IQR) 33-46) were cancer-unaffected and 46 cancer-affected (median age: 44 years, IQR 35-50). The strongest predictor for reaching the reference VO2peak value was attitude towards PA (Odds Ratio 3.0; 95% Confidence Interval 1.3-8.4; p = 0.021). None of the other predictors showed a significant association. A positive attitude towards PA seems to be associated with VO2peak, which should be considered in developing therapeutic and preventive strategies.Trial registrations: NCT02087592; DRKS00005736.


Asunto(s)
Actitud Frente a la Salud , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/prevención & control , Prueba de Esfuerzo , Ejercicio Físico/psicología , Mutación de Línea Germinal , Consumo de Oxígeno , Adulto , Neoplasias de la Mama/etiología , Neoplasias de la Mama/psicología , Estudios Transversales , Femenino , Heterocigoto , Humanos , Persona de Mediana Edad , Estudios Prospectivos , Encuestas y Cuestionarios
5.
Eur Phys J E Soft Matter ; 33(2): 99-103, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20852912

RESUMEN

Cell sorting is a widespread phenomenon pivotal to the early development of multicellular organisms. In vitro cell sorting studies have been instrumental in revealing the cellular properties driving this process. However, these studies have as yet been limited to two-dimensional analysis of three-dimensional cell sorting events. Here we describe a method to record the sorting of primary zebrafish ectoderm and mesoderm germ layer progenitor cells in three dimensions over time, and quantitatively analyze their sorting behavior using an order parameter related to heterotypic interface length. We investigate the cell population size dependence of sorted aggregates and find that the germ layer progenitor cells engulfed in the final configuration display a relationship between total interfacial length and system size according to a simple geometrical argument, subject to a finite-size effect.


Asunto(s)
Separación Celular/métodos , Animales , Agregación Celular , Ectodermo/citología , Mesodermo/citología , Células Madre/citología , Pez Cebra/embriología
6.
J Cell Biol ; 97(3): 849-57, 1983 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-6885921

RESUMEN

Intact, viable sheets of adult rabbit corneal epithelium, 9 mm in diameter, were prepared by the Dispase II method (Gipson, I. K., and S. M. Grill, 1982, Invest. Ophthalmol. Vis. Sci. 23:269-273). The sheets, freed of the basal lamina, retained their desmosomes and stratified epithelial characteristics, but lacked hemidesmosomes (HD). Epithelial sheets were placed on fresh segments of corneal stroma with denuded basal laminae and incubated in serum-free media for 1, 3, 6, 18, or 24 h. Tissue was processed for electron microscopy, and the number of HD/micron membrane, the number of HDs with anchoring fibrils directly across the lamina densa from them, and the number of anchoring fibrils not associated with HDs were counted. After 6 h in culture, the number of newly formed HD was 82% of controls (normal rabbit corneas), and by 24 h the number had reached 95% of controls. At all time periods studied, 80-86% of HDs had anchoring fibrils directly across the lamina densa from them. Anchoring fibrils not associated with HDs decreased with culture time. These data indicate that the sites where anchoring fibrils insert into the lamina densa may be nucleation sites for new HD formation. Corneal epithelial sheets placed on two other ocular basal laminae, Descemet's membrane and lens capsule, had not formed HDs after 24 h in culture. These two laminae do not have anchoring fibrils associated with them. Rabbit epithelial sheets placed on the denuded epithelial basal lamina of rat and human corneas formed new HDs. Thus, at least in these mammalian species, HD formation may involve some of the same molecular components.


Asunto(s)
Membrana Basal/ultraestructura , Adhesión Celular , Desmosomas/ultraestructura , Animales , Córnea/citología , Células Epiteliales , Humanos , Microscopía Electrónica , Conejos , Ratas , Especificidad de la Especie , Factores de Tiempo
7.
J Cell Biol ; 147(4): 743-60, 1999 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-10562278

RESUMEN

We visualized a fluorescent-protein (FP) fusion to Rab6, a Golgi-associated GTPase, in conjunction with fluorescent secretory pathway markers. FP-Rab6 defined highly dynamic transport carriers (TCs) translocating from the Golgi to the cell periphery. FP-Rab6 TCs specifically accumulated a retrograde cargo, the wild-type Shiga toxin B-fragment (STB), during STB transport from the Golgi to the endoplasmic reticulum (ER). FP-Rab6 TCs associated intimately with the ER, and STB entered the ER via specialized peripheral regions that accumulated FP-Rab6. Microinjection of antibodies that block coatomer protein I (COPI) function inhibited trafficking of a KDEL-receptor FP-fusion, but not FP-Rab6. Additionally, markers of COPI-dependent recycling were excluded from FP-Rab6/STB TCs. Overexpression of Rab6:GDP (T27N mutant) using T7 vaccinia inhibited toxicity of Shiga holotoxin, but did not alter STB transport to the Golgi or Golgi morphology. Taken together, our results indicate Rab6 regulates a novel Golgi to ER transport pathway.


Asunto(s)
Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Proteínas de Unión al GTP rab/metabolismo , Animales , Toxinas Bacterianas/toxicidad , Línea Celular , Supervivencia Celular/efectos de los fármacos , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/ultraestructura , Aparato de Golgi/efectos de los fármacos , Aparato de Golgi/ultraestructura , Proteínas Fluorescentes Verdes , Células HeLa , Humanos , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Microscopía Confocal , Microscopía Inmunoelectrónica , Receptores de Péptidos/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Toxinas Shiga , Transfección , Proteínas de Unión al GTP rab/genética
8.
Eur Phys J E Soft Matter ; 30(4): 439-47, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19856004

RESUMEN

We calculate the first-passage time distribution for diffusion through a cylindrical pore with sticky walls. A particle diffusively explores the interior of the pore through a series of binding and unbinding events with the cylinder wall. Through a diagrammatic expansion we obtain first-passage time statistics for the particle's exit from the pore. Connections between the model and nucleocytoplasmic transport in cells are discussed.


Asunto(s)
Difusión , Transporte Biológico , Modelos Químicos , Porosidad , Probabilidad , Factores de Tiempo
9.
J Eur Acad Dermatol Venereol ; 23(1): 52-7, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18702624

RESUMEN

BACKGROUND: Dermatology in a penitentiary environment is an under-researched field. OBJECTIVES: To study the prison population seeking medical advice for skin diseases and to assess among detainees the life impact of these diseases, an approach that to the best of our knowledge has not previously been reported. METHODS: This prospective study was carried out in the male population of two penal institutions in the region of Toulouse, south-western France. RESULTS: One hundred seventy-eight men were seen, for a total of 234 diagnoses and 281 consultations. The five most frequent diagnoses, in order of decreasing frequency, were disorders of the pilosebaceous follicle, fungal diseases, benign skin tumours, warts and eczemas, which are common skin diseases. However, 72% of inmates believed their skin disease was directly related to detention. This belief was related to the conditions of life in prison (seclusion and its effects) and to frequent psychological problems. CONCLUSIONS: The disorders observed were generally benign skin conditions that could be expected in a population of young men living in a closed community. They led to a high demand for care and treatment: skin diseases represented the largest specialist consultation in our institutions. Skin problems can easily be managed in an outpatient unit, which confirms the usefulness of a dedicated dermatology clinic within the outpatient consultation units of penal institutions in order to provide care of equivalent quality to that available in a free environment. The dermatologist can have an important role in the medical management and the health education of prisoners.


Asunto(s)
Prisioneros , Enfermedades de la Piel/epidemiología , Adulto , Francia/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Enfermedades de la Piel/clasificación
10.
Mol Biol Cell ; 12(5): 1481-98, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11359937

RESUMEN

To quantitatively investigate the trafficking of the transmembrane lectin VIP36 and its relation to cargo-containing transport carriers (TCs), we analyzed a C-terminal fluorescent-protein (FP) fusion, VIP36-SP-FP. When expressed at moderate levels, VIP36-SP-FP localized to the endoplasmic reticulum, Golgi apparatus, and intermediate transport structures, and colocalized with epitope-tagged VIP36. Temperature shift and pharmacological experiments indicated VIP36-SP-FP recycled in the early secretory pathway, exhibiting trafficking representative of a class of transmembrane cargo receptors, including the closely related lectin ERGIC53. VIP36-SP-FP trafficking structures comprised tubules and globular elements, which translocated in a saltatory manner. Simultaneous visualization of anterograde secretory cargo and VIP36-SP-FP indicated that the globular structures were pre-Golgi carriers, and that VIP36-SP-FP segregated from cargo within the Golgi and was not included in post-Golgi TCs. Organelle-specific bleach experiments directly measured the exchange of VIP36-SP-FP between the Golgi and endoplasmic reticulum (ER). Fitting a two-compartment model to the recovery data predicted first order rate constants of 1.22 +/- 0.44%/min for ER --> Golgi, and 7.68 +/- 1.94%/min for Golgi --> ER transport, revealing a half-time of 113 +/- 70 min for leaving the ER and 1.67 +/- 0.45 min for leaving the Golgi, and accounting for the measured steady-state distribution of VIP36-SP-FP (13% Golgi/87% ER). Perturbing transport with AlF(4)(-) treatment altered VIP36-SP-GFP distribution and changed the rate constants. The parameters of the model suggest that relatively small differences in the first order rate constants, perhaps manifested in subtle differences in the tendency to enter distinct TCs, result in large differences in the steady-state localization of secretory components.


Asunto(s)
Proteínas Portadoras/metabolismo , Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Lectinas de Unión a Manosa , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Membrana , Transporte de Proteínas , Vesículas Secretoras/metabolismo , Animales , Biomarcadores , Brefeldino A/farmacología , Células COS , Cicloheximida/farmacología , Humanos , Cinética , Proteínas Luminiscentes/metabolismo , Microscopía Confocal , Microscopía por Video , Inhibidores de la Síntesis de la Proteína/farmacología , Transporte de Proteínas/efectos de los fármacos , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Vesículas Secretoras/química , Factores de Tiempo
11.
J Radiol ; 88(9 Pt 2): 1261-3, 2007 Sep.
Artículo en Francés | MEDLINE | ID: mdl-17878872

RESUMEN

The daily practice of radiologists has evolved and radiologists are increasingly being directly involved with patient care and treatment. Consequently, radiologists have become a part of the therapeutic team available to patients. This active role, in hospital based or out-patient practices, does not only have an impact on the radiologist's professional activities. New liabilities related to interventional procedures or treatments are now added to already existing professional liability from diagnostic activities. Therefore, musculoskeletal radiologists performing interventional procedures must be aware and familiar with their obligations towards patients, including the requirement to provide adequate information to patients and documenting that informed consent was obtained.


Asunto(s)
Enfermedades Óseas/terapia , Revelación/legislación & jurisprudencia , Consentimiento Informado/legislación & jurisprudencia , Responsabilidad Legal , Enfermedades Musculares/terapia , Radiología Intervencionista/legislación & jurisprudencia , Atención Ambulatoria/legislación & jurisprudencia , Formularios de Consentimiento/legislación & jurisprudencia , Francia , Humanos , Cuerpo Médico de Hospitales/legislación & jurisprudencia , Grupo de Atención al Paciente/legislación & jurisprudencia
12.
Cancer Res ; 43(5): 2155-8, 1983 May.
Artículo en Inglés | MEDLINE | ID: mdl-6831441

RESUMEN

A series of methotrexate (MTX)-resistant human sublines developed by step increases in selected MTX concentrations have been cloned and examined for dihydrofolate reductase (DHFR) content, relative DNA copy number, and sensitivity to MTX. These cloned sublines had increased DHFR levels which were dependent on the presence of MTX in the medium. The increased levels of DHFR in the absence of MTX were stable in all the clones examined for over a year. Antibody immunolocalization on Western blots showed good correlation of the intensity of the immunostained DHFR band with enzyme activities. Relative gene copy number in these sublines was low relative to the DHFR increases and was not dependent on the presence of MTX in the medium. The increase in gene copy number in these sublines did not correlate with either the levels of DHFR or the sensitivity to MTX.


Asunto(s)
ADN/genética , Metotrexato/farmacología , Tetrahidrofolato Deshidrogenasa/genética , Animales , Línea Celular , ADN/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Electroforesis en Gel de Poliacrilamida , Antagonistas del Ácido Fólico , Genes , Humanos , Leucemia L1210/enzimología , Mutación , Tetrahidrofolato Deshidrogenasa/aislamiento & purificación
13.
Cancer Res ; 44(3): 1252-6, 1984 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-6581868

RESUMEN

Cultured human KB cells which developed resistance to increasing concentrations of methotrexate showed increased levels of dihydrofolate reductase (DHFR) as demonstrated by an immunobridge staining technique. Peripheral blast cells from a leukemic patient were examined for DHFR content during several courses of methotrexate therapy. The number of cells which demonstrated high levels of DHFR increased at the end of treatment. The content in each individual cell was heterogeneous, based on varied intensity of staining in each cell. This immunostaining technique, which utilizes an antibody to DHFR, may have the potential to be a useful tool in the clinic for predicting a patient's possible response to methotrexate therapy.


Asunto(s)
Leucemia Linfoide/enzimología , Tetrahidrofolato Deshidrogenasa/metabolismo , Animales , Carcinoma , Línea Celular , Células Clonales , Resistencia a Medicamentos , Histocitoquímica , Humanos , Inmunoensayo , Leucemia L1210/enzimología , Leucemia Linfoide/tratamiento farmacológico , Metotrexato/uso terapéutico , Ratones , Neoplasias de la Boca
14.
Cancer Res ; 46(10): 5024-8, 1986 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3019519

RESUMEN

Epstein-Barr virus (EBV) has been found to be associated with nasopharyngeal carcinoma (NPC), and antibodies with high frequency and titer to EBV proteins have been found in sera from NPC patients. Raji cells, an EBV genome-carrying nonproducer cell line, treated with 12-O-tetradecanoylphorbol-13-acetate and n-butyrate induced a unique EBV DNA polymerase which has properties similar to the EBV DNA polymerase induced by 12-O-tetradecanoylphorbol-13-acetate in P3HR-1 cells, an EBV producer cell line. The possible presence of antibodies to this EBV DNA polymerase in NPC patient serum was examined. The mean number of EBV DNA polymerase units neutralized was 380 +/- 168 units/ml serum (mean +/- SD) in 48 sera from patients with NPC, whereas that in the sera from 52 healthy donors was 62 +/- 56 units/ml (p less than 0.01). The EBV DNA polymerase antibody was found to be associated with the immunoglobulin G but not the immunoglobulin A fraction, and its titer was not correlated with the titers against EBV DNase or virus capsid antigen-immunoglobulin A. Whether the EBV DNA polymerase antibody is against the EBV DNA polymerase core protein or its stimulating protein is still being investigated. This study demonstrated the high frequency and high titer of antibody against EBV DNA polymerase in serum from NPC patients and suggested the potential of utilizing this antibody titer to complement other methods for the early diagnosis or prognosis of NPC.


Asunto(s)
Anticuerpos Antivirales/análisis , Carcinoma/microbiología , ADN Polimerasa Dirigida por ADN/análisis , Herpesvirus Humano 4/enzimología , Neoplasias Nasofaríngeas/microbiología , Carcinoma/inmunología , Línea Celular , ADN Polimerasa Dirigida por ADN/inmunología , ADN Polimerasa Dirigida por ADN/aislamiento & purificación , Herpesvirus Humano 4/inmunología , Humanos , Neoplasias Nasofaríngeas/inmunología
15.
Cancer Res ; 47(16): 4407-12, 1987 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-3038311

RESUMEN

Phorbol esters and n-butyrate (SB) together could induce Epstein-Barr virus (EBV) DNA polymerase and DNase activities in Raji cells (virus nonproducer). Neither 12-O-tetradecanoylphorbol-13-acetate (TPA) nor SB alone could induce these EBV enzyme activities, transcription of the EcoRI C-region or other EBV proteins in Raji cells. The enzyme induction caused by exposure of Raji cells to TPA-SB was the result of the synthesis of virus-specified RNA, and the increase of linear EBV DNA content in Raji cells caused by TPA alone was not sufficient for induction of EBV-enzyme activities. Temporal characteristics of the TPA-SB induction process, but not the phorbol 12,13-dibutyrate-SB induction process, in Raji cells were observed; a critical phase (10-24 h) postphorbol ester treatment in phorbol 12,13-dibutyrate-SB-treated Raji cells which was responsible for the synthesis of virus RNA and enzymes was found. Phospholipase C, which increases intracellular diacylglycerols (and subsequently activates protein kinase C) was able to partially substitute for TPA in the TPA-SB induction for EBV polymerase and DNase activities. Sphingosine, a protein kinase C inhibitor, partially prevented the induction of virus enzyme activities in Raji cells treated with phorbol 12,13-dibutyrate and SB. No apparent changes in the methylation state of EBV DNA (EcoRI C region) were observed when Raji cells were treated with SB and TPA, alone or in combination. These results suggest that induction of EBV polymerase and DNase activities by TPA-SB may involve protein kinase C activation and another factor triggered by SB which together increase transcription of EBV DNA.


Asunto(s)
Butiratos/farmacología , Genes Virales , Herpesvirus Humano 4/enzimología , Acetato de Tetradecanoilforbol/farmacología , Linfoma de Burkitt/microbiología , Ácido Butírico , Células Cultivadas , ADN Viral/metabolismo , ADN Polimerasa Dirigida por ADN/biosíntesis , Desoxirribonucleasas/biosíntesis , Inducción Enzimática/efectos de los fármacos , Herpesvirus Humano 4/efectos de los fármacos , Herpesvirus Humano 4/genética , Humanos , Metilación , Forbol 12,13-Dibutirato , Ésteres del Forbol/farmacología , Proteína Quinasa C/análisis , Esfingosina/farmacología , Transcripción Genética/efectos de los fármacos
16.
Cancer Res ; 54(14): 3686-91, 1994 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-7518343

RESUMEN

Hydroxyurea (HU) is currently used in the clinic for the treatment of chronic myelogenous leukemia, head and neck carcinoma, and sarcoma. One of its drawbacks, however, is the development of HU resistance. To study this problem, we developed a HU-resistant human KB cell line which exhibits a 15-fold resistance to HU. The characterization of this HU-resistant phenotype revealed a gene amplification of the M2 subunit of ribonucleotide reductase (RR), increased levels of M2 mRNA and protein, and a 3-fold increase of RR activity. This HU-resistant cell line also expressed a "collateral sensitivity" to 6-thioguanine (6-TG), with a 10-fold decrease in the dose inhibiting cell growth by 50% as compared to the KB parental line. The mechanism responsible for this supersensitivity to 6-TG is believed to be related to an increasingly efficient conversion of 6-TG to its triphosphate form, which is subsequently incorporated into DNA. After passage of the resistant cells in the absence of HU, the cell line reverts. The revertant cells lose their resistance to HU and concomitantly their sensitivity to 6-TG. This phenomenon is due to the return of RR to levels comparable to that of the KB parental cell line. These observations and their relevance to cancer chemotherapy will be discussed in this paper. Our results suggest that a clinical protocol could be designed which would allow for a lower dose of 6-TG to be used by taking advantage of the increased RR activity in HU-refractory cancer patients. Two drugs which display collateral sensitivity are known as a "Ying-Yang" pair. Alternate treatment with two different Ying-Yang pairs is the rationale for the "Ying-Yang Ping-Pong" theory in cancer treatment. This rationale allows for effective cancer chemotherapy with reduced toxicity.


Asunto(s)
Hidroxiurea/farmacología , Tioguanina/farmacología , Animales , Secuencia de Bases , ADN/metabolismo , Resistencia a Medicamentos , Humanos , Células KB , Ratones , Datos de Secuencia Molecular , ARN/metabolismo
17.
Biochim Biophys Acta ; 652(1): 90-8, 1981 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-6260189

RESUMEN

Phosphonoformate inhibited the replication of Herpes simplex virus (HSV) type 1 and type 2 in culture. The concentration required to inhibit the replication of both types of virus by 2 logs at 28 h post-infection was approximately 150 microM. It was more potent than phosphonoacetate against the growth of both virus types. A virus mutant which is resistant to phosphonoacetate was cross-resistant to phosphonoformate. Arsonoacetate, at 300 microM, had no antivirus activity. Phosphonoformate also inhibited HeLa and KB cell growth; at a concentration of about 500 microM, cell growth was inhibited by 50%. The anti-cell growth effects of the drug were completely reversible. The antivirus effect of phosphonoformate was partially reversible, depending on the time and duration of exposure of infected cultures to the drug. To obtain the maximum antivirus effect, phosphonoformate had to be added within the first 3 h post-virus-infection and be continuously present for at least 18 h. Phosphonoformate, added at 0 h post-infection, suppressed the induction of virus-specific DNA polymerase and DNAase activities. dTMP incorporation into DNA was preferentially inhibited in nuclei isolated from infected cells compared to uninfected cells, and the degree of inhibition varied with the ionic strength of the assay. Phosphonoformate was a potent inhibitor of the purified HSV-1 and HSV-2 DNA polymerases, inhibiting DNA polymerase activity by 50% at a concentration of 3 microM and ionic strength of 0.2.


Asunto(s)
Antivirales/farmacología , Compuestos Organofosforados/farmacología , Ácido Fosfonoacético/farmacología , Simplexvirus/efectos de los fármacos , División Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Células Cultivadas , ADN/biosíntesis , ADN Polimerasa Dirigida por ADN/biosíntesis , Inducción Enzimática/efectos de los fármacos , Foscarnet , Células HeLa/metabolismo , Ácido Fosfonoacético/análogos & derivados , Factores de Tiempo , Replicación Viral/efectos de los fármacos
18.
FEBS Lett ; 495(3): 167-71, 2001 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-11334885

RESUMEN

Sequence determinants and structural features of the RNA govern mRNA-ribosome interaction in bacteria. However, ribosomal recruitment to leaderless mRNAs, which start directly with the AUG start codon and do not bear a Shine-Dalgarno sequence like canonical mRNAs, does not appear to rely on 16S rRNA-mRNA interactions. Here, we have studied the effects of translation initiation factors IF2 and IF3 on 30S initiation at a 5'-terminal AUG and at a competing downstream canonical ribosome binding site. We show that IF2 affects the forward kinetics of 30S initiation complex formation at the 5'-terminal AUG as well as the stability of these complexes. Moreover, the IF2:IF3 molar ratio was found to play a decisive role in translation initiation of a leaderless mRNA both in vitro and in vivo indicating that the translational efficiency of an mRNA is not only intrinsically determined but can be altered depending on the availability of components of the translational machinery.


Asunto(s)
Codón Iniciador , Factores de Iniciación de Péptidos/farmacología , Biosíntesis de Proteínas , Ribosomas/metabolismo , Escherichia coli/genética , Factor 3 de Iniciación Eucariótica , Genes Reporteros , Sustancias Macromoleculares , Factores de Iniciación de Péptidos/metabolismo , Factor 2 Procariótico de Iniciación , ARN de Transferencia de Metionina/metabolismo , Transformación Genética
19.
Neurology ; 44(1): 70-6, 1994 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8290095

RESUMEN

We treated focal hand dystonia in 53 patients with botulinum toxin injections for up to 6 years. Eighty-one percent of the patients improved with at least one injection session. Sixty-five percent of the injections produced transient weakness. We followed 37 of the patients for at least 2 years from the start of treatment, 24 of whom discontinued treatment because of inadequate response, loss of response, inaccessibility of a treatment provider, or the expense of the toxin. Women, who had a greater extent and longer duration of benefit than men, were more likely to continue treatment. The mean interval between injection sessions was 6 months. In most patients, we injected the toxin into the same combination of muscles at each session. The dose of toxin generally fluctuated within a range of 20 units. Side effects were mild and transient and unrelated to the long-term use of botulinum toxin. Botulinum toxin injection is safe and effective for the long-term management of focal hand dystonia.


Asunto(s)
Toxinas Botulínicas/uso terapéutico , Distonía/tratamiento farmacológico , Adulto , Anciano , Toxinas Botulínicas/administración & dosificación , Distonía/etiología , Distonía/fisiopatología , Femenino , Mano , Humanos , Masculino , Persona de Mediana Edad , Calambre Muscular/tratamiento farmacológico , Calambre Muscular/etiología , Calambre Muscular/fisiopatología , Factores de Tiempo , Resultado del Tratamiento
20.
J Med Chem ; 30(11): 2154-7, 1987 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2822932

RESUMEN

5-Ethynyl-1-beta-D-arabinofuranosylcytosine (EAC) was prepared from 1-(2,3,5-tri-O-acetyl-beta-D-arabinofuranosyl)cytosine by iodination followed by coupling with (trimethylsilyl)acetylene and deblocking. At 50 microM, EAC was found to inhibit the in vitro replication of herpes simplex virus type 1 and type 2 by greater than 99%. EAC also showed activity against a strain of HSV-1 resistant to (E)-5-(2-bromovinyl)-2'-deoxyuridine which has an alteration of the virus-induced thymidine kinase (TK). At 100 microM, EAC did not inhibit the in vitro growth of leukemia L1210 and HeLa cells. EAC was resistant to the action of dCR-CR deaminase, its rate of deamination being approximately 2% that of dCR. The compound was a poor substrate for dCR kinase, but it was phosphorylated by HSV-1- and HSV-2-induced TKs at 50% and 30%, respectively, the rate of thymidine.


Asunto(s)
Antivirales/síntesis química , Citarabina/análogos & derivados , Antivirales/metabolismo , Antivirales/farmacología , Citarabina/síntesis química , Citarabina/farmacología , Desaminación , Fosforilación , Simplexvirus/efectos de los fármacos
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