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1.
Neurosci Lett ; 795: 137027, 2023 01 31.
Artículo en Inglés | MEDLINE | ID: mdl-36566831

RESUMEN

Adult neurogenesis is an aspect of structural plasticity that remains active during adulthood in some brain regions. One of them is the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. Adult neurogenesis is reduced by different factors and in disorders of the CNS, including major depression. Antidepressant treatments, such as chronic fluoxetine administration, recover the normal level of adult neurogenesis. Fluoxetine treatment increases the free concentration of the neurotransmitter serotonin and this monoamine is implicated in the regulation of the neurogenic process; however, the target of the action of this neurotransmitter has not been fully elucidated. In this study, we have tried to determine the relevance of the serotonin receptor 3 (5-HT3) in the hippocampal neurogenesis of adult rats. We have used fluorescent immunohistochemistry to study the expression of the 5-HT3 receptor in different neurogenesis stages in the SGZ, identifying its expression in stem cells, amplifying neural progenitors and immature neurons. Moreover, we have studied the impact of a 5-HT3 antagonist (ondansetron) in the fluoxetine-induced adult neurogenesis. We observed that fluoxetine alone increases the number of both proliferating cells (ki67 positive) and immature neurons (DCX positive) in the SGZ. By contrast, co-treatment with ondansetron blocked the increase in proliferation and neurogenesis. This study demonstrates that the activation of 5-HT3 receptors is necessary for the increase of adult neurogenesis induced by fluoxetine.


Asunto(s)
Fluoxetina , Células-Madre Neurales , Ratas , Animales , Fluoxetina/farmacología , Fluoxetina/metabolismo , Receptores de Serotonina 5-HT3/metabolismo , Ondansetrón/metabolismo , Hipocampo/metabolismo , Neurogénesis/fisiología , Células-Madre Neurales/metabolismo , Proliferación Celular , Giro Dentado/metabolismo
2.
Public Health ; 144: 96-102, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28274391

RESUMEN

OBJECTIVES: We aimed to study the risk of developing post-traumatic stress disorder (PTSD) symptoms in people who resided in an affected area by an extremely severe flood, and sociodemographic risk factors associated with this condition. STUDY DESIGN: A geographic information system (GIS) was used to distribute the rainfall data. A case-control study was developed to study the relationship between PTSD and sociodemographic risk factors. METHODS: To delineate the areas affected by the flood and the intensity of this rainfall in comparison with historical hydrological data, we employed geographical information systems (GIS). Then, we recruited a representative sample of the affected population and another population sample that lived at the time of this disaster in adjacent geographical areas that were not affected. Both groups were randomly selected in primary care practices, from December 1st 2012 to January 31st 2013. All participants, 70 from the affected areas and 91 from the non-affected, filled a sociodemographic questionnaire and the trauma questionnaire (TQ) to identify and rate PTSD symptoms. RESULTS: Our GIS analysis confirmed that the amount of precipitation in 2012 in the areas affected by the flood was exceptionally high compared with historical average rainfall data (461l per square metre vs 265). Individuals who resided in the affected areas at the time of the flood were at much higher risk of developing PTSD symptoms (OR: 8.18; 95% CI: 3.99-17.59) than those living in adjacent, non-affected localities. Among the sociodemographic variables included in this study, only material and financial losses were strongly associated with the onset of PTSD (P < 0.001). Physical risk during this life-threatening catastrophe also indicated a positive correlation with later development of PTSD symptoms; however, it did not reach statistical significance (P = 0.06). CONCLUSIONS: Populations affected by severe floods may suffer an increase of PTSD symptoms in the following months. This finding, along with the importance of material losses as a predictor for such disorder, may help develop effective plans to minimize the negative impact of these natural disasters on public health.


Asunto(s)
Inundaciones , Trastornos por Estrés Postraumático/epidemiología , Estrés Psicológico/epidemiología , Sobrevivientes/psicología , Adolescente , Adulto , Estudios de Casos y Controles , Desastres , Femenino , Sistemas de Información Geográfica , Humanos , Incidencia , Acontecimientos que Cambian la Vida , Masculino , Persona de Mediana Edad , Factores de Riesgo , Factores Socioeconómicos , Trastornos por Estrés Postraumático/psicología , Estrés Psicológico/psicología , Encuestas y Cuestionarios , Sobrevivientes/estadística & datos numéricos
3.
Rheumatol Int ; 35(9): 1609-13, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25847702

RESUMEN

There are few high-quality instruments to evaluate the participation and social functioning of fibromyalgia patients. The Fibromyalgia Participation Questionnaire (FPQ) is a questionnaire that evaluates these aspects with high reliability and validity in its German original version. The aim of this work was to describe the translation and cross-cultural adaptation process of the FPQ into Spanish and its validation to ensure the equivalence against the original version. The questionnaire will be translated according to the FACIT methodology, and it will be tested in the Clinical Management Unit of North Almeria Health Area. This methodology includes several stages: double forward translation, reconciled version, back-translation, review of the previous versions and development of the prefinal version for the pretest. Once the pretest ends, the final version of the questionnaire will be developed, which will be subjected to a validation process to study its psychometric properties. Reliability will be studied by internal consistency and test-retest reliability through Cronbach's alpha and Pearson's correlation coefficient, respectively. External and construct validity will be analysed using correlation coefficients, content validity with an empirical analysis, and a differential item functioning analysis will be employed to measure discriminative validity. The presence of ceiling and floor effects will be calculated too. The validation of the FPQ into different languages will allow better evaluation and treatment based on the observed limitations fibromyalgia patients suffer from, as well as bringing the possibility to compare between other countries and generalize its use in the scientific community.


Asunto(s)
Fibromialgia/psicología , Proyectos de Investigación , Encuestas y Cuestionarios , Protocolos Clínicos , Comparación Transcultural , Fibromialgia/diagnóstico , Humanos , Psicometría , Traducciones
4.
Top Curr Chem ; 286: 121-49, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-23563612

RESUMEN

Since the discovery of paclitaxel and its peculiar mechanism of cytotoxicity, which has made it and its analogues widely used antitumour drugs, great effort has been made to understand the way they produce their effect in microtubules and to find other products that share this effect without the undesired side effects of low solubility and development of multidrug resistance by tumour cells. This chapter reviews the actual knowledge about the biochemical and structural mechanisms of microtubule stabilization by microtubule stabilizing agents, and illustrates the way paclitaxel and its biomimetics induce microtubule assembly, the thermodynamics of their binding, the way they reach their binding site and the conformation they have when bound.

5.
Actas Urol Esp ; 31(7): 705-13, 2007.
Artículo en Español | MEDLINE | ID: mdl-17902462

RESUMEN

BACKGROUND: New approaches for prostate cancer are needed due to limitations of current therapies for the treatment in advanced stages of the disease. In fact, there is no effective treatment for these patients. Development in molecular biology research on prostate cancer has improved the knowledge of common alterations encoded in DNA sequence, which may be useful as targets for prostate cancer approach. In this review we give an overview of current gene therapy concepts, the most common gene alterations in prostate cancer and the gene therapy treatment strategies.


Asunto(s)
Vacunas contra el Cáncer , Terapia Genética , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/prevención & control , Vectores Genéticos , Humanos , Masculino
6.
Neurosci Biobehav Rev ; 30(3): 276-91, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16081158

RESUMEN

The purpose of the present study was: first, to offer a few theoretical considerations on the concept of human aggression and its main types; and second, to analyse the relationship between those types of aggression and other related psychological constructs, such as anger, hostility, and impulsivity, summarizing the main empirical results of our research in progress. In order to assess their eventual correlations, several self-report techniques were compared: (a) AQ, used to measure several kinds of aggression, anger, and hostility; (b) CAMA, a questionnaire already used in a variety of cultures, for measuring attitudes toward interpersonal aggression in different instrumental and hostile situations; (c) ASQ, an instrument for measuring experienced anger and its expression in assertive or aggressive ways; and (d) BIS, used to prove three impulsiveness sub-traits: motor, attentional, and non-planning impulsiveness. The different definitions of aggression may be grouped according to whether the primary goal is distress or harm, focusing primarily on the objective infliction of harm, or on the subjective intention of harming. Most classifications in the literature show two kinds of aggression, even if different names are used: Hostile Aggression (among other names it is also known as 'reactive, impulsive, or affective') is an act primarily oriented to hurt another individual; and Instrumental Aggression (also known as 'proactive, premeditated, or predative') is a means or tool for solving problems or for obtaining a variety of objectives. As predicted, there was a positive correlation between experience and expression of anger. Anger involved physiological arousal and prepared for aggression. Anger and impulsiveness were also positively correlated with hostile aggression, but not with instrumental aggression. In the case of impulsiveness, non-planning impulsiveness was positively correlated with some situations related to hostile aggression, such as emotional agitation or lack of communication, but not with instrumental one. Finally, hostility positively correlated with anger and different kinds of aggression, but not its degree of justification. In sum, aggression can be reflected in the different personality constructs, measured by self-reports.


Asunto(s)
Agresión/fisiología , Ira/fisiología , Hostilidad , Conducta Impulsiva/fisiopatología , Humanos
7.
Bull Soc Pathol Exot ; 96(3): 196-9, 2003 Aug.
Artículo en Francés | MEDLINE | ID: mdl-14582295

RESUMEN

UNLABELLED: Since the Diama dam on the Senegal river became operative in 1986, an exceptional outbreak of intestinal schistosomiasis occurred in northern Senegal. This is the first case report from this region of a splenorenal derivation performed in Dakar to cure decompensated portal hypertension due to Schistosoma mansoni. CASE REPORT: In June 1998, a 16-year old boy, native from Richard-Toll in the Senegal River Basin, was admitted to the paediatric department of Hôpital Principal, Dakar, Senegal, with a 3 years of recurrent hematemesis. Blood transfusions were required despite propranolol and multiple oesophageal varices sclerotherapies. On admission he weighed 33 kg and was noted to have pallor and moderate hepatosplenomegaly. Lab work included normal liver function tests, a Hgb of 58 mg/L, negative HBs antigen, and high titers of schistosomiasis antibodies (> 1/2000 by the hemagglutination method). Ultrasound revealed an homogeneously enlarged liver, periportal fibrosis and spleen with a grade 2 portal hypertension (WHO score). Endoscopy showed stage 3 oesophageal varices with red spots but no active haemorrhage. After transfusions, a Warren distal splenorenal anastomosis was performed. During the operation, a liver biopsy was obtained, showing periportal fibrosis and schistosomiasis granulomas. The patient was discharged without complication. After 4 years he remains free of any recurrence of his upper gastrointestinal haemorrhage and haemoglobin rate is normal. COMMENTS: Before the inauguration of the dam in 1986, S. mansoni infection was never reported from the Senegal River Basin. But as early as 1988, the first cases of intestinal schistosomiasis began to show up. A few years later, this focus had dramatically extended and in 1991 the first cases of hepatic fibrosis were detected in ultrasonography surveys. The present case involves the first patient from northern Senegal who required surgery for haemorrhagic complications of schistosomiasis induced by liver disease. Considering the high prevalence in this area, and the difficulties of medical management, the need for porto-systemic derivations is likely to rise. These operations are difficult and require specially trained surgeons. They have been largely unavailable in Senegal until now. This case report, involving a child only 10 years after the beginning of the epidemic, underlines the acute need for improving both prevention and medical treatment in order to avoid progression to clinical stages of hepatic schistosomiasis where surgery is unavoidable. In addition, the training of local surgical teams able to deal with these complications is urgently needed in Senegal.


Asunto(s)
Hipertensión Portal/parasitología , Hipertensión Portal/cirugía , Derivación Portosistémica Quirúrgica , Esquistosomiasis mansoni/complicaciones , Adolescente , Animales , Anticuerpos Antihelmínticos/sangre , Transfusión Sanguínea , Várices Esofágicas y Gástricas/parasitología , Humanos , Riñón , Masculino , Schistosoma mansoni/inmunología , Senegal , Bazo
8.
Curr Cancer Drug Targets ; 3(3): 193-203, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12769688

RESUMEN

Microtubules are highly dynamic cellular polymers made of alphabeta-tubulin and associated proteins. They play a key role during mitosis, participating in the exact organization and function of the spindle, and are critical for assuring the integrity of the segregated DNA. Therefore, they represent one of the more effective targets in current cancer therapy. Paclitaxel (Taxol) is the prototype of the taxane family of antitumor drugs, and it was the first natural product shown to stabilize microtubules. This unique mechanism of action is in contrast to other microtubule poisons, such as Vinca alkaloids, colchicine, and cryptophycines, which inhibit tubulin polymerization. Taxanes block cell cycle progression through centrosomal impairment, induction of abnormal spindles and suppression of spindle microtubule dynamics. Triggering of apoptosis by aberrant mitosis or by subsequent multinucleated G1-like state related to mitotic slippage, depends on cell type and drug schedule. The development of fluorescent derivatives of paclitaxel led us to locate spindle pole microtubules and centrosomes as main sub-cellular targets of cytotoxic taxoids in living cells. In this review we discuss these findings in the context of a cell cycle-dependent response to taxanes, based on the cellular targets, and the status of the implicated cell cycle checkpoints. We also review those events that can influence this response, like the different signal transduction pathways activated/inactivated in relation to Bcl-2 phosphorylation and induction of apoptosis, and the controversial role of the p53 status on cell sensitivity to paclitaxel. Finally, cell cycle-dependent resistance, an emerging concept in combination sequential chemotherapy, is discussed on the basis of the cell cycle-dependent mechanisms of action of taxanes.


Asunto(s)
Ciclo Celular/efectos de los fármacos , Centrosoma/efectos de los fármacos , Sistemas de Liberación de Medicamentos/métodos , Microtúbulos/efectos de los fármacos , Paclitaxel/farmacología , Animales , Ciclo Celular/fisiología , Centrosoma/fisiología , Humanos , Microtúbulos/fisiología , Paclitaxel/uso terapéutico , Paclitaxel/toxicidad
10.
Med Trop (Mars) ; 62(3): 242-3, 2002.
Artículo en Francés | MEDLINE | ID: mdl-12244919

RESUMEN

Most patients admitted to African surgical departments require emergency procedures. Etiologies involve a wide variety of diseases that are only rarely tropical. However the poor general status of patients and underdeveloped sanitary conditions can alter symptomatic presentation and require modified surgical techniques. The adverse conditions under which in the southern hemisphere is now performed will not change without improvement in general living standards and health-care infrastructure of the countries involved.


Asunto(s)
Países en Desarrollo , Servicio de Urgencia en Hospital/estadística & datos numéricos , Salud Pública , Procedimientos Quirúrgicos Operativos/estadística & datos numéricos , Medicina Tropical , África , Servicio de Urgencia en Hospital/normas , Estado de Salud , Humanos , Clase Social , Procedimientos Quirúrgicos Operativos/normas
11.
Biochemistry ; 40(40): 11975-84, 2001 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-11580273

RESUMEN

The ubiquitous Taxol binding site of microtubules also binds newly discovered ligands. We have designed a homogeneous assay for the high throughput detection of Taxol biomimetics, based on the displacement of 7-O-[N-(2,7-difluoro-4'-fluoresceincarbonyl)-L-alanyl]Taxol from its binding site in diluted solutions of preserved microtubules. The state of this reference ligand is measured by fluorescence anisotropy in a microplate reader, with varying concentrations of nonfluorescent competitors. The binding equilibrium constant of Taxol has a value K(b) = 3.7 x 10(7) M(-1). We have found that baccatin III, an analogue of Taxol without the C-13 side chain, binds with K(b) = 1.5 x 10(5) M(-1), whereas the side chain methyl ester is inactive. This was unexpected from the structure-activity relationship of taxoids but compatible with models of Taxol docked at the microtubule site. Baccatin III binding has been confirmed by displacement of [(3)H]Taxol and by direct HPLC measurements of its cosedimentation with microtubules, among other methods. Consequently, baccatin III induces microtubule bundles and multipolar spindles in PtK2 and U937 cells, and mitotic arrest and apoptotic death of the U937 cells, at concentrations 200-500-fold larger than Taxol. The simplest analysis of these results strongly suggests that the interaction of the C-2 C-4 substituted taxane ring system with the microtubule binding site provides most (ca. 75%) of the free energy change of Taxol binding and is sufficient to activate microtubule stabilization and transmit the antitumor effects of Taxol, whereas the C-13 side chain provides a weak specific anchor.


Asunto(s)
Alcaloides/metabolismo , Antineoplásicos Fitogénicos/metabolismo , Colorantes Fluorescentes/metabolismo , Microtúbulos/metabolismo , Paclitaxel/metabolismo , Taxoides , Animales , Bovinos , Cromatografía Líquida de Alta Presión , Citometría de Flujo , Humanos , Microscopía Fluorescente , Paclitaxel/análogos & derivados , Espectrometría de Fluorescencia , Relación Estructura-Actividad , Células U937
12.
Cell Motil Cytoskeleton ; 49(1): 1-15, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11309836

RESUMEN

Microtubules offer a very large local concentration of binding sites for cytotoxic taxoids or for hypothetical endogenous regulators. Several compounds from diverse sources stabilize microtubules and arrest cell division similarly to the antitumour drug Taxol. We have investigated the subcellular location of the Taxol binding sites, employing a fluorescent taxoid (FLUTAX) that reversibly interacts with the Taxol binding sites of microtubules and induces cellular effects similar to Taxol. The specific binding of FLUTAX to a fraction of the available cellular binding sites effectively inhibits division of cultured human tumour cells at G(2)/M, and triggers apoptotic death. The loci of reversible binding, directly imaged in intact U937 cells treated with cytotoxic doses of fluorescent taxoid are the centrosomes, with a few associated microtubules in interphase cells, and the spindle pole microtubules in mitotic cells, instead of uniformly labelling the microtubule cytoskeleton. Cytoskeletal lesions induced and visualized with FLUTAX consist of microtubule bundles and abnormal mitoses, including monopolar spindles and highly fluorescent multipolar spindles. The multiple asters and monopolar spindles mark arrested U937 leukaemia and OVCAR-3 ovarian carcinoma cells on their path to apoptosis (as well as K562, HeLa, and MCF-7 cells). Depending on the FLUTAX treatment, OVCAR-3 cells died from abnormal mitosis or from a subsequent interphase with double chromatin content and lobulated nuclei (micronuclei), indicating impairment of centrosome separation. Fragmented centrosomes could be observed in FLUTAX-treated non-transformed 3T3.A31 cells, which developed micronuclei but were resistant to apoptosis. These results strongly suggest that centrosomal impairment by taxoid binding during interphase, in addition to the suppression of the kinetochore microtubule dynamics in the mitotic spindle, is a primary cause of cell cycle de-regulation and cell death.


Asunto(s)
Muerte Celular/efectos de los fármacos , Centrosoma/efectos de los fármacos , Microtúbulos/efectos de los fármacos , Paclitaxel/análogos & derivados , Paclitaxel/farmacología , Taxoides , Sitios de Unión , Ciclo Celular/efectos de los fármacos , Centrosoma/metabolismo , Citometría de Flujo , Humanos , Microscopía Fluorescente , Microtúbulos/metabolismo , Paclitaxel/metabolismo , Células U937/efectos de los fármacos
13.
J Biol Chem ; 276(20): 17307-15, 2001 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-11278786

RESUMEN

The effect of bound nucleotide on the conformation of cell division protein FtsZ from Methanococcus jannaschii has been investigated using molecular dynamics and site-directed mutagenesis. The molecular dynamics indicate that the gamma-phosphate of GTP induces a conformational perturbation in loop T3 (Gly88-Gly99 segment), in a position structurally equivalent to switch II of Ha-ras-p21. In the simulated GTP-bound state, loop T3 is pulled by the gamma-phosphate into a more compact conformation than with GDP, related to that observed in the homologous proteins alpha- and beta-tubulin. The existence of a nucleotide-induced structural change in loop T3 has been confirmed by mutating Thr92 into Trp (T92W-W319Y FtsZ). This tryptophan (12 A away from gamma-phosphate) shows large differences in fluorescence emission, depending on which nucleotide is bound to FtsZ monomers. Loop T3 is located at a side of the contact interface between two FtsZ monomers in the current model of FtsZ filament. Such a structural change may bend the GDP filament upon hydrolysis by pushing against helix H8 of next monomer, thus, generating force on the membrane during cell division. A related curvature mechanism may operate in tubulin activation.


Asunto(s)
Proteínas Arqueales/química , Proteínas Arqueales/metabolismo , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Methanococcus/fisiología , Secuencia de Aminoácidos , Proteínas Arqueales/genética , Sitios de Unión , División Celular , Glicina , Methanococcus/citología , Methanococcus/genética , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Conformación Proteica , Estructura Secundaria de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo
14.
Bioorg Med Chem Lett ; 10(22): 2549-51, 2000 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-11086727

RESUMEN

The 3,4,5-trimethoxyphenyl and 3-hydroxy-4-methoxyphenyl rings of combretastatin A-4 are deemed optimal for its activity as antimitotic agent. The replacement of either one by a naphthalene ring results in compounds with a potency comparable to that of the parent compound. These results show that the naphthalene ring is a good surrogate for the 3,4,5-trimethoxyphenyl or the 3-hydroxy-4-methoxyphenyl rings of combretastatin A-4 and that neither of them is essential for the antitumor activity.


Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Naftalenos/química , Estilbenos/síntesis química , Estilbenos/farmacología , Antineoplásicos/química , Estilbenos/química , Relación Estructura-Actividad
15.
J Mol Biol ; 299(5): 1289-302, 2000 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-10873453

RESUMEN

We have reconstructed, from experimental approximately 2 nm resolution X-ray solution scattering profiles, the corresponding shapes and sizes of myoglobin, troponin C, spermadhesin PSP-I/PSP-II, chymotrypsinogen A, superoxide dismutase, ovalbumin, tubulin, nitrite reductase, catalase, the structural change of troponin C upon dissociation of the two high affinity Ca(2+), and the solution model structure of a tandem pair of fibronectin type III cytoplasmic domains of integrin alpha6beta4 before determination of its crystal structure. To this purpose we have designed a new genetic algorithm which gradually explores a discrete search space and evolves convergent models made of several hundred beads (down to 0.3 nm radius) best fitting the scattering profile upon Debye calculation, without geometrical constraints or penalty for loose beads. This is a procedure of effective numerical transformation of the one-dimensional scattering profiles into three-dimensional model structures. The number of beads in models is correlated with the protein molecular mass (with one exception). The shape and approximate dimensions of each protein have been retrieved by a set of ten solution models, essentially superimposable with the available crystal structures.


Asunto(s)
Algoritmos , Modelos Genéticos , Modelos Moleculares , Proteínas/química , Proteínas/genética , Animales , Calcio/farmacología , Cristalografía por Rayos X , Datos de Secuencia Molecular , Peso Molecular , Mutación/genética , Estructura Cuaternaria de Proteína/efectos de los fármacos , Estructura Terciaria de Proteína/efectos de los fármacos , Soluciones , Difracción de Rayos X/métodos
16.
Cancer Res ; 60(10): 2651-9, 2000 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-10825137

RESUMEN

We have found that the bicyclic colchicine analogue 2-methoxy-5-(2',3',4'-trimethoxyphenyl)-2,4,6-cycloheptatrien-1-on e (MTC) induced a dose- and time-dependent apoptotic response in human leukemic cells. MTC and colchicine rapidly disrupted the microtubule integrity and arrested cells at the G2-M phase before the onset of apoptosis. These responses were mediated by microtubule inhibition because 2-methoxy-5-[[3-(3,4,5-trimethoxyphenyl)propionyl]amino]-2,4,6-cycloh eptatrien-1-one and lumicolchicine, inactive analogues of MTC and colchicine, respectively, were unable to promote microtubule disassembly, cell cycle arrest, and apoptosis. Although 1 microM MTC induced a complete microtubule disruption after 1 h of incubation in human leukemic HL-60 cells that led to an accumulation of cells at the G2-M phase, MTC-induced apoptosis occurred after 9 h of treatment. This indicates the existence of a rather long lag between microtubule disruption and the onset of apoptosis. Unlike colchicine, the removal of MTC during this lag resulted in rapid microtubule repolymerization, followed by restoration of normal cell cycle and cell growth. MTC, but not 2-methoxy-5-[[3-(3,4,5-trimethoxyphenyl)-propionyl]amino]-2,4,6-cyclo heptatrien-1-one, induced c-jun expression as well as c-Jun NH2-terminal kinase and caspase activation, indicating that these signaling pathways are triggered by the specific action of MTC on microtubules. Caspase inhibition prevented MTC-induced apoptosis. Overexpression of bcl-2 or bcl-xL by gene transfer in human erythroleukemic HEL cells abrogated MTC-induced apoptosis, but cells remained arrested in G2-M, suggesting that bcl-2 and bcl-xL block the signaling pathway between G2-M arrest and triggering of apoptosis. MTC-treated bcl-2 and bcl-xL-transfected HEL cells recovered their capacity to proliferate after MTC removal. These results indicate that microtubule inhibition induces G2-M arrest and apoptosis in leukemic cells, showing a lag phase between G2-M arrest and the onset of apoptosis, regulated by bcl-2 and bcl-xL, during which MTC displays a reversible action on microtubule depolymerization and G2-M cell cycle arrest. Thus, MTC is a potent apoptotic inducer on human leukemic cells and shows a remarkable reversible action on microtubule network and cell cycle before commitment for apoptosis is reached.


Asunto(s)
Anisoles/farmacología , Apoptosis/efectos de los fármacos , Ciclo Celular , Cicloheptanos/farmacología , Microtúbulos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-bcl-2/fisiología , Caspasas/metabolismo , División Celular , Colchicina/farmacología , Activación Enzimática , Inducción Enzimática , Células HL-60 , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos , Proteínas Quinasas Activadas por Mitógenos/biosíntesis , Mitosis , Modelos Químicos , Proteína bcl-X
17.
J Biol Chem ; 275(34): 26265-76, 2000 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-10818101

RESUMEN

We have determined the kinetic scheme and the reaction rates of binding to microtubules of two fluorescent taxoids, 7-O-[N-(4'-fluoresceincarbonyl)-l-alanyl]Taxol (Flutax-1) and 7-O-[N-(2,7-difluoro-4'-fluoresceincarbonyl)-l-alanyl]Taxol (Flutax-2). Flutax-1 and Flutax-2 bind to microtubules with high affinity (K(a) approximately 10(7) m(-1), 37 degrees C). The binding mechanism consists of a fast bimolecular reaction followed by at least two monomolecular rearrangements, which were characterized with stopped-flow techniques. The kinetic constants of the bimolecular reaction were 6.10 +/- 0.22 x 10(5) m(-1) s(-1) and 13.8 +/- 1.8 x 10(5) m(-1) s(-1) at 37 degrees C, respectively. A second slow binding step has been measured employing the change of fluorescence anisotropy of the probe. The reversal of this reaction is the rate-limiting step of dissociation. A third step has been detected using small angle x-ray scattering and involves a 2-nm increase in the diameter of microtubules. It is suggested that the first step entails the binding of the Taxol moiety and the second a relative immobilization of the fluorescent probe. The equilibrium and some kinetic measurements required the use of stabilized cross-linked microtubules, which preserved taxoid binding. The results indicate that the Taxol binding site is directly accessible, in contrast with its location at lumen in the current model of microtubules. An alternative structural model is considered in which the binding site is located between protofilaments, accessible from the microtubule surface.


Asunto(s)
Colorantes Fluorescentes/metabolismo , Microtúbulos/metabolismo , Paclitaxel/análogos & derivados , Taxoides , Animales , Sitios de Unión , Bovinos , Docetaxel , Cinética , Modelos Moleculares , Paclitaxel/metabolismo , Dispersión de Radiación , Espectrometría de Fluorescencia , Termodinámica , Tubulina (Proteína)/metabolismo , Rayos X
18.
J Biol Chem ; 275(16): 11740-9, 2000 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-10766796

RESUMEN

The bacterial cell division protein FtsZ from Escherichia coli has been purified with a new calcium precipitation method. The protein contains one GDP and one Mg(2+) bound, it shows GTPase activity, and requires GTP and Mg(2+) to polymerize into long thin filaments at pH 6.5. FtsZ, with moderate ionic strength and low Mg(2+) concentrations, at pH 7.5, is a compact and globular monomer. Mg(2+) induces FtsZ self-association into oligomers, which has been studied by sedimentation equilibrium over a wide range of Mg(2+) and FtsZ concentrations. The oligomer formation mechanism is best described as an indefinite self-association, with binding of an additional Mg(2+) for each FtsZ monomer added to the growing oligomer, and a slight gradual decrease of the affinity of addition of a protomer with increasing oligomer size. The sedimentation velocity of FtsZ oligomer populations is compatible with a linear single-stranded arrangement of FtsZ monomers and a spacing of 4 nm. It is proposed that these FtsZ oligomers and the polymers formed under assembly conditions share a similar axial interaction between monomers (like in the case of tubulin, the eukaryotic homolog of FtsZ). Similar mechanisms may apply to FtsZ assembly in vivo, but additional factors, such as macromolecular crowding, nucleoid occlusion, or specific interactions with other cellular components active in septation have to be invoked to explain FtsZ assembly into a division ring.


Asunto(s)
Proteínas Bacterianas/química , Proteínas del Citoesqueleto , Magnesio/farmacología , Calcio/farmacología , Dicroismo Circular , GTP Fosfohidrolasas/metabolismo , Nucleótidos de Guanina/farmacología , Modelos Moleculares , Polímeros/química , Conformación Proteica/efectos de los fármacos , Pliegue de Proteína , Estructura Secundaria de Proteína , Soluciones , Relación Estructura-Actividad
19.
Med Trop (Mars) ; 59(2): 157-60, 1999.
Artículo en Francés | MEDLINE | ID: mdl-10546189

RESUMEN

Since emergency transfer of patients from Africa to European cardiovascular facilities is difficult, surgeons at the Principal Hospital in Dakar, Senegal, have reevaluated closed mitral commissurotomy. The purpose of this study was to ascertain patient selection criteria, optimal operative conditions, immediate and middle-term outcome, and cost of closed mitral commissurotomy. From June 1995 to March 1998, closed mitral commissurotomy was carried out on 21 patients (13 women and 8 men). Inclusion criteria were symptomatic mitral stenosis with a mitral surface less than 1.5 square centimeters. Exclusion criteria were associated valve disease, Wilkins score higher than 8, severe pulmonary artery hypertension, and evidence of mitral thrombus. One patient died on the fourth postoperative day and one patient developed transient hemiparesis. Twenty patients showed significant functional improvement. Mean mitral surface increased from 0.87 to 1.8 square centimeters. Follow-up at one-year confirmed stable results. Only one patient developed grade 3 mitral insufficiency but it was well tolerated and did not require valve replacement. The cost of the procedure was 1,000,000 F CFA in second category and 820,000 F CFA in third category. The findings of this study show that closed mitral commissurotomy can be performed without circulatory assistance equipment in African facilities such as the Principal Hospital in Dakar, that immediate and middle-term results are excellent, and that African surgeons should continue to learn the technique.


Asunto(s)
Cateterismo/métodos , Estenosis de la Válvula Mitral/terapia , Adolescente , Adulto , Cateterismo/efectos adversos , Cateterismo/economía , Cateterismo/mortalidad , Países en Desarrollo , Femenino , Cirugía General/educación , Humanos , Hipertensión Pulmonar/etiología , Masculino , Persona de Mediana Edad , Estenosis de la Válvula Mitral/clasificación , Estenosis de la Válvula Mitral/complicaciones , Estenosis de la Válvula Mitral/diagnóstico , Selección de Paciente , Estudios Prospectivos , Senegal , Índice de Severidad de la Enfermedad , Trombosis/etiología , Resultado del Tratamiento
20.
Chirurgie ; 124(4): 406-11, 1999 Sep.
Artículo en Francés | MEDLINE | ID: mdl-10546394

RESUMEN

AIM OF THE STUDY: The aim of this prospective study was to report early results of videothoracoscopic truncal vagotomy in non-complicated chronic duodenal ulcers. PATIENTS AND METHODS: From 1995 to 1998, 250 patients suffering from chronic duodenal ulcer without pyloric stenosis were operated on in the main hospital of Dakar. They underwent videothoracoscopic truncal vagotomy without gastric drainage. The quality of gastric emptying and the incidence of secondary side-effects were assessed in the postoperative course and after one and three months. RESULTS: There were two intraoperative deaths, one due to aortic wound and the other one due to a poor surveillance after premature extubation. Postoperative complications included bronchopulmonary infection (n = 9), one septic pleural effusion and one chylothorax. A postoperative gastroplegia occurred in 12 patients, which was always spontaneously regressive without endoscopic pyloric dilatation. After one month, 204 patients (82%) were classified Visik 1, and 44 (18%) classified Visik 2. An endoscopic control examination showed a healed peptic ulcer and open pylorus in all patients, and a gastric stasis present in 40 cases (16%). After three months and a new evaluation, 234 were classified Visik 1 (94%) and 14 Visik 2 (6%). Dumping syndrome was not observed in this series and the incidence of diarrhea, which was 40% after one month, decreased to 3% after three months. CONCLUSION: The functional results of truncular vagotomy without gastric drainage were good or very good and improved with time. The quality of digestive comfort and the low frequency of side-effects are good arguments in favor of this procedure as an elective treatment of duodenal ulcers in developing countries.


Asunto(s)
Úlcera Duodenal/cirugía , Cirugía Torácica Asistida por Video , Vagotomía Troncal , Adulto , Causas de Muerte , Enfermedad Crónica , Quilotórax/etiología , Países en Desarrollo , Diarrea/etiología , Drenaje , Síndrome de Vaciamiento Rápido/prevención & control , Femenino , Estudios de Seguimiento , Vaciamiento Gástrico/fisiología , Gastroparesia/etiología , Humanos , Incidencia , Complicaciones Intraoperatorias , Enfermedades Pulmonares/microbiología , Masculino , Derrame Pleural/etiología , Estudios Prospectivos , Senegal , Cirugía Torácica Asistida por Video/efectos adversos , Vagotomía Troncal/efectos adversos , Cicatrización de Heridas
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