Los autores agradecen el apoyo financiero del presupuesto estatal de la Agencia de Investigación de Eslovenia y el proyecto de la Comisión Europea ESOPE (QLK-2002-02003), financiado por el 5 º Programa Marco. Los autores reconocen la contribución del prof. Marko Snoj, prof. Maja Cemazar, Matej Merkac y Likon Rado en la preparación de este video-artículo.

El procedimiento de tratamiento de electroquimioterapia consiste en la inyección de drogas local o sistémica, seguida de la entrega de los pulsos eléctricos aplicados en el tumor 1. Información detallada sobre el tratamiento se ha publicado en los Procedimientos Operativos Estándar (SOP) 2. Indicaciones de tratamiento: <ol><li> Tipo de tumores: carcinoma de células basales y las metástasis cutáneas de melanoma maligno, carcinoma de mama, hipernefroma, sarcoma de Kaposi y otros. </li><li> Localización del tumor: cutánea accesible y nódulos subcutáneos tumor en todas las partes del cuerpo. </li><li> Tamaño del tumor puede ser de 3 mm a 5.3 cm de diámetro. </li><li> Número de nódulos, de 1 a 100. </li></ol> Procedimiento de tratamiento: <ol><li> Anestesia local o general, dependiendo del número de los nódulos tratados y la ubicación. </li><li> La elección de medicamentos: cisplatino o bleomicina. Cisplatino y bleomicina puede ser inyectado intratumoral, bleomicina también por vía intravenosa en una dosis de 15.000 UI / m 2. Dosis inyectada para la aplicación intratumoral de bleomicina es 250-1000 UI / cm 3 de tejido tumoral y de cisplatino 0,5 -1 mg / cm 3 de tejido tumoral </li><li> Intervalo de tiempo entre la administración del fármaco y la aplicación de pulsos eléctricos, después de la inyección intratumoral de la droga de inmediato, después de la administración por vía intravenosa después de 8 min. hasta 28 min. </li><li> Eléctrica del generador de impulsos para electroquimioterapia debe proporcionar los impulsos eléctricos de onda cuadrada de amplitud 1000 V o más, frecuencia de repetición de 1 Hz a 5 kHz. </li><li> Pulso eléctrico parámetros: por ejemplo, 8 pulsos de 1000 V a una distancia de 8 mm entre dos electrodos de placa, la frecuencia de 1 Hz y 5 kHz, duración del pulso de 100 ms. </li><li> Si todo el tumor no puede ser abarcada entre los electrodos, la aplicación de pulsos eléctricos se deben repetir muchas veces para cubrir toda el área del tumor, incluyendo márgenes de seguridad. </li><li> Tipo de electrodo: electrodos de placa se utilizan para pequeños nódulos, tumores superficiales, electrodos de aguja son para el tratamiento de semillas más nódulos bajo la piel. </li></ol> Otras características del tratamiento: <ol><li> Por lo general, un solo tratamiento es eficaz para la erradicación de nódulo tumoral, sin embargo electroquimioterapia se pueden repetir en intervalos de 4 semanas en el tejido tumoral residual o nódulos de otros tumores. </li></ol> Debido a la falta de toxicidad sistémica - ya que las dosis muy baja de bleomicina o cisplatino es necesario - los pacientes pueden ser tratados en forma ambulatoria, y pueden dejar el hospital poco después del tratamiento.

<ol>
	<li>Mir, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bases+and+rationale+of+the+electrochemotherapy.">Bases and rationale of the electrochemotherapy.</a> EJC Suppl. 4, 38-44 (2006).</li><li>Mir, L. M., Gehl, J., Sersa, G., Collins, C. G., Garbay, J. R., Billard, V., Geertsen, P., Rudolf, Z., O'Sullivan, G. C., Marty, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+operating+procedures+of+the+electrochemotherapy:+instructions+for+the+use+of+bleomycin+or+cisplatin+administered+either+systemically+or+locally+and+electric+pulses+delivered+by+the+CliniporatorTM+by+means+of+invasive+or+non-invasive+electrodes.">Standard operating procedures of the electrochemotherapy: instructions for the use of bleomycin or cisplatin administered either systemically or locally and electric pulses delivered by the CliniporatorTM by means of invasive or non-invasive electrodes.</a> EJC Suppl. 4, 14-25 (2006).</li><li>Okino, M., Mohri, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+high-voltage+electrical+impulse+and+an+anticancer+drug+on+in+vivo+growing+tumors.">Effects of high-voltage electrical impulse and an anticancer drug on in vivo growing tumors.</a> Jpn. J. Cancer Res. 78, 1319-1321 (1987).</li><li>Mir, L. M., Banoun, H., Paoletti, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Introduction+of+definite+amounts+of+nonpermeant+molecules+into+living+cells+after+electropermeabilization:+direct+access+to+the+cytosol.">Introduction of definite amounts of nonpermeant molecules into living cells after electropermeabilization: direct access to the cytosol.</a> Exp. Cell Res. 175, 15-25 (1988).</li><li>Sersa, G., Cemazar, M., Miklavcic, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antitumor+effectiveness+of+electrochemotherapy+with+cis-diamminedichloroplatinum(II)+in+mice.">Antitumor effectiveness of electrochemotherapy with cis-diamminedichloroplatinum(II) in mice.</a> Cancer Res. 55, 3450-3455 (1995).</li><li>Sersa, G., Cemazar, M., Miklavcic, D., Rudolf, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemotherapy+of+tumours.">Electrochemotherapy of tumours.</a> Radiol. Oncol. 40, 163-174 (2006).</li><li>Miklavcic, D., Beravs, K., Semrov, D., Cemazar, M., Demsar, F., Sersa, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+importance+of+electric+field+distribution+for+effective+in+vivo+electroporation+of+tissues.">The importance of electric field distribution for effective in vivo electroporation of tissues.</a> Biophys. J. 74, 2152-2158 (1998).</li><li>Miklavcic, D., Corovic, S., Pucihar, G., Pavselj, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Importance+of+tumour+coverage+by+sufficiently+high+local+electric+field+for+effective+electrochemotherapy.">Importance of tumour coverage by sufficiently high local electric field for effective electrochemotherapy.</a> EJC Suppl. 4, 45-51 (2006).</li><li>Sersa, G., Jarm, T., Kotnik, T., Coer, A., Podkrajsek, M., Sentjurc, M., Miklavcic, D., Kadivec, M., Kranjc, S., Secerov, A., Cemazar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascular+disrupting+action+of+electroporation+and+electrochemotherapy+with+bleomycin+in+murine+sarcoma.">Vascular disrupting action of electroporation and electrochemotherapy with bleomycin in murine sarcoma.</a> Brit. J. Cancer. 98, 388-398 (2008).</li><li>Mir, L. M., Belehradek, M., Domenge, C., Orlowski, S., Poddevin, B., Belehradek, J., Schwaab, G., Luboinski, B., Paoletti, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemotherapy,+a+new+antitumor+treatment:+first+clinical+trial.">Electrochemotherapy, a new antitumor treatment: first clinical trial.</a> C. R. Acad. Sci. III. 313, (1991).</li><li>Mir, L. M., Glass, L. F., Sersa, G., Teissie, J., Domenge, C., Miklavcic, D., Jaroszeski, M. J., Orlowski, S., Reintgen, D. S., Rudolf, Z., Belehradek, M., Gilbert, R., Rols, M. P., Belehradek, J., Bachaud, J. M., DeConti, R., Stabuc, B., Cemazar, M., Coninx, P., Heller, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effective+treatment+of+cutaneous+and+subcutaneous+malignant+tumours+by+electrochemotherapy.">Effective treatment of cutaneous and subcutaneous malignant tumours by electrochemotherapy.</a> Brit. J. Cancer. 77, 2336-2342 (1998).</li><li>Gothelf, A., Mir, L. M., Gehl, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemotherapy:+results+of+cancer+treatment+using+enhanced+delivery+of+bleomycin+by+electroporation.">Electrochemotherapy: results of cancer treatment using enhanced delivery of bleomycin by electroporation.</a> Cancer Treat. Rev. 29, 371-387 (2003).</li><li>Byrne, C. M., Thompson, J. F., Johnston, H., Hersey, P., Quinn, M. J., Hughes, M., McCarthy, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+of+metastatic+melanoma+using+electroporation+therapy+with+bleomycin+(electrochemotherapy).">Treatment of metastatic melanoma using electroporation therapy with bleomycin (electrochemotherapy).</a> Melanoma Res. 15, 45-51 (2005).</li><li>Sersa, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+state-of-the-art+of+electrochemotherapy+before+the+ESOPE+study:+advantages+and+clinical+uses.">The state-of-the-art of electrochemotherapy before the ESOPE study: advantages and clinical uses.</a> EJC Suppl. 4, 52-59 (2006).</li><li>Sersa, G., Miklavcic, D., Cemazar, M., Rudolf, Z., Pucihar, G., Snoj, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemotherapy+in+treatment+of+tumours.">Electrochemotherapy in treatment of tumours.</a> EJSO. 34, 232-240 (2008).</li><li>Marty, M., Sersa, G., Garbay, J. R., Gehl, J., Collins, C. G., Snoj, M., Billard, V., Geertsen, P. F., Larkin, J. O., Miklavcic, D., Pavlovic, I., Paulin-Kosir, S. M., Cemazar, M., Morsli, N., Soden, D. M., Rudolf, Z., Robert, C., O'Sullivan, G. C., Mir, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemotherapy+-+an+easy,+highly+effective+and+safe+treatment+of+cutaneous+and+subcutaneous+metastases:+results+of+ESOPE+(European+Standard+Operating+Procedures+of+Electrochemotherapy)+study.">Electrochemotherapy - an easy, highly effective and safe treatment of cutaneous and subcutaneous metastases: results of ESOPE (European Standard Operating Procedures of Electrochemotherapy) study.</a> EJC Suppl. 4, 3-13 (2006).</li><li>Quaglino, P., Mortera, C., Osella-Abate, S., Barberis, M., Illengo, M., Rissone, M., Savoia, P., Bernengo, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemotherapy+with+intravenous+bleomycin+in+the+local+treatment+of+skin+melanoma+metastases.">Electrochemotherapy with intravenous bleomycin in the local treatment of skin melanoma metastases.</a> Ann. Surg. Oncol. 15, 2215-2222 (2008).</li></ol>

Aumento de la citotoxicidad de la bleomicina por la exposición de las células a pulsos eléctricos electroporative fue descrito por primera vez por Okino M y Mir LM 3,4. A partir de entonces electroquimioterapia demostró ser eficaz también para el cisplatino 5. Gran cantidad de datos preclínicos se recogieron in vitro y en modelos de tumores in vivo en los años siguientes. La efectividad del tratamiento se determinó en relación con la dosis del fármaco, la vía de su administración, el momento de la inyección de drogas y la aplicación de pulsos eléctricos, la intensidad del campo eléctrico, la cobertura con campo eléctrico lo suficientemente alto (E), y una selección adecuada de los electrodos y su posicionamiento con respecto al tumor 1,6,7,8. Además, los mecanismos que subyacen a la efectividad de electroquimioterapia fueron elaborados, lo que demuestra que, además de un efecto directo de electroquimioterapia a las células tumorales, efecto vascular perturbar y la respuesta inmune están implicados 1,6,9. Todos estos datos recogidos permitió la traducción de electroquimioterapia en las clínicas. Los primeros ensayos clínicos demostraron la eficacia de electroquimioterapia en la cabeza y el cuello y los nódulos tumorales de melanoma 10. Más tarde, su eficacia fue demostrada en otros tipos de tumores, como el carcinoma de células basales de la piel, las metástasis cutáneas de melanoma, tumores de mama, el hipernefroma y el sarcoma de Kaposi. Hay varios informes de evaluación en conjunto todos los datos clínicos publicados sobre electroquimioterapia con bleomicina y cisplatino 11-15. En general, la tasa de respuesta de los tumores tratados fue de aproximadamente 80% de respuestas objetivas y aproximadamente el 70% de respuestas completas 15,16. La eficacia puede ser aún mayor por el tratamiento repetitivo 17. Todos estos datos clínicos han permitido electroquimioterapia a adoptar en algunos países europeos como el tratamiento estándar, con intención paliativa, en varios tumores. El futuro de este tratamiento consiste en introducir electroquimioterapia en el tratamiento de tumores internos y las metástasis, y en el tratamiento combinado, ya sea con la terapia génica o terapia de radiación. Estos intentos están en curso.

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<td>Bleomycin (Blenamax)</td>
<td>Reagent</td>
<td>Pharmachemie B.V.</td>
<td>&nbsp;</td>
<td>chemotherapeutic drug used in electrochemotherapy </td>
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<td>Cliniporator</td>
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electrochemotherapy of tumours

Electroquimioterapia es un uso combinado de ciertos fármacos de quimioterapia y los pulsos eléctricos aplicados en el nódulo tumoral tratada. La aplicación local de impulsos eléctricos en el tumor aumenta de administración de fármacos en las células, específicamente en el sitio de la aplicación de pulsos eléctricos. La absorción de la droga mediante la entrega de impulsos eléctricos se incrementa sólo para los fármacos de quimioterapia y su transporte a través de la membrana plasmática se ve impedida. Entre los muchos medicamentos que se han probado hasta ahora, bleomicina y cisplatino encontrado el camino de las pruebas preclínicas para el uso clínico. Datos clínicos recogidos en una serie de estudios clínicos indican que aproximadamente el 80% de la cutánea tratados y los nódulos subcutáneos tumor de diferentes tumores malignos se encuentran en una respuesta objetiva, de estos, aproximadamente el 70% en respuesta completa después de una sola aplicación de electroquimioterapia. Por lo general, sólo un tratamiento es necesario, sin embargo, electroquimioterapia se puede repetir varias veces cada pocas semanas con la misma efectividad en cada ocasión. Los resultados del tratamiento en una efectiva erradicación de los nódulos tratados, con un buen efecto estético, sin tejido cicatrizal.

Watch this Scientific Journal Video about Electrochemotherapy of Tumours at JoVE.com

Electrochemotherapy of Tumours

Electroquimioterapia es un uso combinado de ciertos fármacos quimioterápicos como el cisplatino y bleomicina y los pulsos eléctricos aplicados en el nódulo tumoral tratada. Se presenta el protocolo clínico de electroquimioterapia para Treatmen de subcutáneo y metástasis cutáneas de melanoma.

Electroquimioterapia de tumores

Electrochemotherapy is a combined use of certain chemotherapeutic drugs and electric pulses applied to the treated tumour nodule. Local application of ...

Research

JoVE Journal

Biology

24.4K vistas.  Institute of Oncology Ljubljana. Electroquimioterapia es un uso combinado de ciertos fármacos quimioterápicos como el cisplatino y bleomicina y los pulsos eléctricos aplicados en el nódulo tumoral tratada. Se presenta el protocolo clínico de electroquimioterapia para Treatmen de subcutáneo y metástasis cutáneas de melanoma.

Video: Electrochemotherapy of Tumours

Retrograde Labeling of Retinal Ganglion Cells by Application of Fluoro-Gold on the Surface of Superior Colliculus

Retinal ganglion cell (RGC) counting is essential to evaluate retinal degeneration especially in glaucoma. Reliable RGC labeling is fundamental for evaluating the effects of any treatment. In rat, about 98% of RGCs is known to project to the contralateral superior colliculus (SC) (Forrester and Peters, 1967). Applying fluoro-gold (FG) on the surface of SC can label almost all the RGCs, so that we can focus on this most vulnerable retinal neuron in glaucoma. FG is taken up by the axon terminals of retinal ganglion cells and bilaterally transported retrogradely to its somas in the retina. Compare with retrograde labeling of RGC by putting FG at stump of transected optic nerve for 2 days, the interference of RGC survival is minimized. Compare with cresyl violet staining that stains RGCs, amacrine cells and endothelium of the blood vessel in the retinal ganglion cell layer, this labeling method is more specific to the RGC. This video describes the method of retrograde labeling of RGC by applying FG on the surface of SC. The surgical procedures include drilling the skull; aspirating the cortex to expose the SC and applying gelatin sponge over entire dorsal surface of SC are shown. Useful tips for avoiding massive intracranial bleeding and aspiration of the SC have been given.

This video describes the method of retrograde labeling of RGC by applying fluoro-gold (FG) on the surface of superior colliculus (SC). Technique involves drilling the skull, aspirating the cortex, and applying gelatin sponge over entire dorsal surface of SC.

Etiquetado retrógrada de las células ganglionares de la retina por la aplicación de Fluoro-Gold en la superficie del colículo superior

Retinal ganglion cell (RGC) counting is essential to evaluate retinal degeneration especially in glaucoma. Reliable RGC labeling is fundamental for ...

Investigación

Biología

Isolation of Protoplasts from Tissues of 14-day-old Seedlings of Arabidopsis thaliana

Protoplasts are plant cells that have had their cell walls enzymatically removed. Isolation of protoplasts from different plant tissues was first reported more than 40 years ago 1 and has since been adapted to study a variety of cellular processes, such as subcellular localization of proteins, isolation of intact organelles and targeted gene-inactivation by double stranded RNA interference (RNAi) 2-5. Most of the protoplast isolation protocols use leaf tissues of mature Arabidopsis (e.g. 35-day-old plants) 2-4. We modified existing protocols by employing 14-day-old Arabidopsis seedlings. In this procedure, one gram of 14-day-old seedlings yielded 5 106-107 protoplasts that remain intact at least 96 hours. The yield of protoplasts from seedlings is comparable with preparations from leaves of mature Arabidopsis, but instead of 35-36 days, isolation of protoplasts is completed in 15 days. This allows decreasing the time and growth chamber space that are required for isolating protoplasts when mature plants are used, and expedites the downstream studies that require intact protoplasts.

Isolation of Protoplasts from Tissues of 14-day-old Seedlings of Arabidopsis thaliana

This video shows a procedure for isolating intact protoplasts from tissues of 14-day-old seedlings of Arabidopsis. Given that the isolated protoplasts remain intact for at least 96h and are isolated from seedlings instead of one-month-old mature plants, this procedure expedites assays requiring intact protoplasts.

El aislamiento de protoplastos a partir de tejidos de 14 días de edad de las plántulas Arabidopsis thaliana</em

Protoplasts are plant cells that have had their cell walls enzymatically removed. Isolation of protoplasts  from different plant tissues was first ...

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Transient kinetic analysis is indispensable for understanding the workings of biological macromolecules, since this approach yields mechanistic information including active site concentrations and intrinsic rate constants that govern macromolecular function. In case of enzymes, for example, transient or pre-steady state measurements identify and characterize individual events in the reaction pathway, whereas steady state measurements only yield overall catalytic efficiency and specificity. Individual events such as protein-protein or protein-ligand interactions and rate-limiting conformational changes often occur in the millisecond timescale, and can be measured directly by stopped-flow and chemical-quench flow methods. Given an optical signal such as fluorescence, stopped-flow serves as a powerful and accessible tool for monitoring reaction progress from substrate binding to product release and catalytic turnover1,2.
Here, we report application of stopped-flow kinetics to probe the mechanism of action of Msh2-Msh6, a eukaryotic DNA repair protein that recognizes base-pair mismatches and insertion/deletion loops in DNA and signals mismatch repair (MMR)3-5. In doing so, Msh2-Msh6 increases the accuracy of DNA replication by three orders of magnitude (error frequency decreases from ~10-6 to10-9 bases), and thus helps preserve genomic integrity. Not surprisingly, defective human Msh2-Msh6 function is associated with hereditary non-polyposis colon cancer and other sporadic cancers6-8. In order to understand the mechanism of action of this critical DNA metabolic protein, we are probing the dynamics of Msh2-Msh6 interaction with mismatched DNA as well as the ATPase activity that fuels its actions in MMR. DNA binding is measured by rapidly mixing Msh2-Msh6 with DNA containing a 2-aminopurine (2-Ap) fluorophore adjacent to a G:T mismatch and monitoring the resulting increase in 2-aminopurine fluorescence in real time. DNA dissociation is measured by mixing pre-formed Msh2-Msh6 G:T(2-Ap) mismatch complex with unlabeled trap DNA and monitoring decrease in fluorescence over time9. Pre-steady state ATPase kinetics are measured by the change in fluorescence of 7-diethylamino-3-((((2-maleimidyl)ethyl)amino)carbonyl) coumarin)-labeled Phosphate Binding Protein (MDCC-PBP) on binding phosphate (Pi) released by Msh2-Msh6 following ATP hydrolysis9,10.
The data reveal rapid binding of Msh2-Msh6 to a G:T mismatch and formation of a long-lived Msh2-Msh6 G:T complex, which in turn results in suppression of ATP hydrolysis and stabilization of the protein in an ATP-bound form. The reaction kinetics provide clear support for the hypothesis that ATP-bound Msh2-Msh6 signals DNA repair on binding a mismatched base pair in the double helix.
F. Noah Biro and Jie Zhai contributed to this paper equally.

Msh2-Msh6 is responsible for initiating repair of replication errors in DNA. Here we present a transient kinetics approach towards understanding how this critical protein works. The report illustrates stopped-flow experiments for measuring the coupled DNA binding and ATPase kinetics underlying Msh2-Msh6 mechanism of action in DNA repair.

Aplicación de métodos de flujo detenido Cinética para investigar el mecanismo de acción de una proteína de reparación del ADN

Transient kinetic analysis is indispensable for understanding the workings of biological macromolecules, since this approach yields mechanistic ...

Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats

Preimplantation embryos from cattle, sheep, and goats may be cryopreserved for short- or long-term storage. Preimplantation embryos consist predominantly of water, and the avoidance of intracellular ice crystal formation during the cryopreservation process is of paramount importance to maintain embryo viability. Embryos are placed into a hypertonic solution (1.4 &#x2013; 1.5 M) of a cryoprotective agent (CPA) such as ethylene glycol (EG) or glycerol (GLYC) to create an osmotic gradient that facilitates cellular dehydration. After embryos reach osmotic equilibrium in the CPA solution, they are individually loaded in the hypertonic CPA solution into 0.25 ml plastic straws for freezing. Embryos are placed into a controlled rate freezer at a temperature of -6&deg;C. Ice crystal formation is induced in the CPA solution surrounding the embryo, and crystallization causes an increase in the concentration of CPA outside of the embryo, causing further cellular dehydration. Embryos are cooled at a rate of 0.5&deg;C/min, enabling further dehydration, to a temperature of -34&deg;C before being plunged into liquid nitrogen (-196&deg;C). Cryopreserved embryos must be thawed prior to transfer to a recipient (surrogate) female. Straws containing the embryos are removed from the liquid nitrogen dewar, held in room temperature air for 3 to 5 sec, and placed into a 37&deg;C water bath for 25 to 30 sec. Embryos cryopreserved in GLYC are placed into a 1 M solution of sucrose for 10 min for removal of the CPA before transfer to a recipient (surrogate) female. Embryos cryopreserved in EG, however, may be directly transferred to the uterus of a recipient.

Preimplantation embryos may be cryopreserved after placement into a hypertonic cryoprotective solution to cause cellular dehydration. After equilibration, ice crystal formation is induced in the solution surrounding the embryo. Further dehydration occurs as the embryo is slowly cooled to subzero temperatures before plunging into liquid nitrogen for storage.

La criopreservación de embriones de preimplantación de ganado, ovejas y cabras

Preimplantation embryos from cattle, sheep, and goats may be cryopreserved for short- or long-term storage.  Preimplantation embryos consist predominantly ...

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c

Apoptosis, or programmed cell death, is a conserved and highly regulated pathway by which cells die1. Apoptosis can be triggered when cells encounter a wide range of cytotoxic stresses. These insults initiate signaling cascades that ultimately cause the release of cytochrome c from the mitochondrial intermembrane space to the cytoplasm2. The release of cytochrome c from mitochondria is a key event that triggers the rapid activation of caspases, the key cellular proteases which ultimately execute cell death3-4.
The pathway of apoptosis is regulated at points upstream and downstream of cytochrome c release from mitochondria5. In order to study the post-mitochondrial regulation of caspase activation, many investigators have turned to direct cytoplasmic microinjection of holocytochrome c (heme-attached) protein into cells6-9. Cytochrome c is normally localized to the mitochondria where attachment of a heme group is necessary to enable it to activate apoptosis10-11. Therefore, to directly activate caspases, it is necessary to inject the holocytochrome c protein instead of its cDNA, because while the expression of cytochrome c from cDNA constructs will result in mitochondrial targeting and heme attachment, it will be sequestered from cytosolic caspases. Thus, the direct cytosolic microinjection of purified heme-attached cytochrome c protein is a useful tool to mimic mitochondrial cytochrome c release and apoptosis without the use of toxic insults which cause cellular and mitochondrial damage.
In this article, we describe a method for the microinjection of cytochrome c protein into cells, using mouse embryonic fibroblasts (MEFs) and primary sympathetic neurons as examples. While this protocol focuses on the injection of cytochrome c for investigations of apoptosis, the techniques shown here can also be easily adapted for microinjection of other proteins of interest.

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c

In this protocol, we describe the direct cytoplasmic microinjection of cytochrome c protein into fibroblasts and primary sympathetic neurons. This technique allows for the introduction of cytochrome c protein into the cytoplasm of cells and mimics the release of cytochrome c from mitochondria, which occurs during apoptosis.

La activación de la apoptosis mediante microinyección citoplasmática del citocromo C</em

Apoptosis, or programmed cell death, is a conserved and highly regulated pathway by which cells die1.  Apoptosis can be triggered when cells encounter a ...

Application of MassSQUIRM for Quantitative Measurements of Lysine Demethylase Activity

Recently, epigenetic regulators have been discovered as key players in many different diseases 1-3. As a result, these enzymes are prime targets for small molecule studies and drug development 4. Many epigenetic regulators have only recently been discovered and are still in the process of being classified. Among these enzymes are lysine demethylases which remove methyl groups from lysines on histones and other proteins. Due to the novel nature of this class of enzymes, few assays have been developed to study their activity. This has been a road block to both the classification and high throughput study of histone demethylases. Currently, very few demethylase assays exist. Those that do exist tend to be qualitative in nature and cannot simultaneously discern between the different lysine methylation states (un-, mono-, di- and tri-). Mass spectrometry is commonly used to determine demethylase activity but current mass spectrometric assays do not address whether differentially methylated peptides ionize differently. Differential ionization of methylated peptides makes comparing methylation states difficult and certainly not quantitative (Figure 1A). Thus available assays are not optimized for the comprehensive analysis of demethylase activity.
Here we describe a method called MassSQUIRM (mass spectrometric quantitation using isotopic reductive methylation) that is based on reductive methylation of amine groups with deuterated formaldehyde to force all lysines to be di-methylated, thus making them essentially the same chemical species and therefore ionize the same (Figure 1B). The only chemical difference following the reductive methylation is hydrogen and deuterium, which does not affect MALDI ionization efficiencies. The MassSQUIRM assay is specific for demethylase reaction products with un-, mono- or di-methylated lysines. The assay is also applicable to lysine methyltransferases giving the same reaction products. Here, we use a combination of reductive methylation chemistry and MALDI mass spectrometry to measure the activity of LSD1, a lysine demethylase capable of removing di- and mono-methyl groups, on a synthetic peptide substrate 5. This assay is simple and easily amenable to any lab with access to a MALDI mass spectrometer in lab or through a proteomics facility. The assay has ~8-fold dynamic range and is readily scalable to plate format 5.

We present a method for using MALDI mass spectrometry and reductive methylation chemistry to quantify changes in lysine methylation.

Aplicación de MassSQUIRM para mediciones cuantitativas de la actividad desmetilasa Lisina

Recently, epigenetic regulators have been discovered as key players in many different diseases 1-3. As a result, these enzymes are prime targets for small ...

Identification of Post-translational Modifications of Plant Protein Complexes

Plants adapt quickly to changing environments due to elaborate perception and signaling systems. During pathogen attack, plants rapidly respond to infection via the recruitment and activation of immune complexes. Activation of immune complexes is associated with post-translational modifications (PTMs) of proteins, such as phosphorylation, glycosylation, or ubiquitination. Understanding how these PTMs are choreographed will lead to a better understanding of how resistance is achieved.
Here we describe a protein purification method for nucleotide-binding leucine-rich repeat (NB-LRR)-interacting proteins and the subsequent identification of their post-translational modifications (PTMs). With small modifications, the protocol can be applied for the purification of other plant protein complexes. The method is based on the expression of an epitope-tagged version of the protein of interest, which is subsequently partially purified by immunoprecipitation and subjected to mass spectrometry for identification of interacting proteins and PTMs.
This protocol demonstrates that: i). Dynamic changes in PTMs such as phosphorylation can be detected by mass spectrometry; ii). It is important to have sufficient quantities of the protein of interest, and this can compensate for the lack of purity of the immunoprecipitate; iii). In order to detect PTMs of a protein of interest, this protein has to be immunoprecipitated to get a sufficient quantity of protein.

We describe here a protocol for the purification and characterization of plant protein complexes. We demonstrate that by immunoprecipitating a single protein within a complex, so we can identify its post-translational modifications and its interacting partners.

Identificación de modificaciones post-traduccionales de la proteína vegetal Complejos

Plants adapt quickly to changing environments due to elaborate perception and signaling systems. During pathogen attack, plants rapidly respond to ...

A Method of Permeabilization of Drosophila Embryos for Assays of Small Molecule Activity

The Drosophila embryo has long been a powerful laboratory model for elucidating molecular and genetic mechanisms that control development. The ease of genetic manipulations with this model has supplanted pharmacological approaches that are commonplace in other animal models and cell-based assays. Here we describe recent advances in a protocol that enables application of small molecules to the developing fruit fly embryo. The method details steps to overcome the impermeability of the eggshell while maintaining embryo viability. Eggshell permeabilization across a broad range of developmental stages is achieved by application of a previously described d-limonene embryo permeabilization solvent (EPS1) and by aging embryos at reduced temperature (18 &#176;C) prior to treatments. In addition, use of a far-red dye (CY5) as a permeabilization indicator is described, which is compatible with downstream applications involving standard red and green fluorescent dyes in live and fixed preparations. This protocol is applicable to studies using bioactive compounds to probe developmental mechanisms as well as for studies aimed at evaluating teratogenic or pharmacologic activity of uncharacterized small molecules.

A Method of Permeabilization of Drosophila Embryos for Assays of Small Molecule Activity

Introduction of small molecules to the developing Drosophila embryo offers great potential for characterizing biological activity of novel compounds, drugs, and toxins as well as for probing fundamental developmental pathways. Methods described herein outline steps that overcome natural barriers to this approach, expanding the utility of the Drosophila embryo model.

Un método de permeabilización de<em&gt; Drosophila</em&gt; Los embriones para ensayos de moléculas pequeñas Actividad

The Drosophila embryo has long been a powerful laboratory model for elucidating molecular and genetic mechanisms that control development. The ease of ...

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

Red/near-infrared light therapy (R/NIR-LT), delivered by laser or light emitting diode (LED), improves functional and morphological outcomes in a range of central nervous system injuries in vivo, possibly by reducing oxidative stress. However, effects of R/NIR-LT on oxidative stress have been shown to vary depending on wavelength or intensity of irradiation. Studies comparing treatment parameters are lacking, due to absence of commercially available devices that deliver multiple wavelengths or intensities, suitable for high through-put in vitro optimization studies. This protocol describes a technique for delivery of light at a range of wavelengths and intensities to optimize therapeutic doses required for a given injury model. We hypothesized that a method of delivering light, in which wavelength and intensity parameters could easily be altered, could facilitate determination of an optimal dose of R/NIR-LT for reducing reactive oxygen species (ROS) in vitro.
Non-coherent Xenon light was filtered through narrow-band interference filters to deliver varying wavelengths (center wavelengths of 440, 550, 670 and 810nm) and fluences (8.5 x 10-3 to 3.8 x 10-1 J/cm2) of light to cultured cells. Light output from the apparatus was calibrated to emit therapeutically relevant, equal quantal doses of light at each wavelength. Reactive species were detected in glutamate stressed cells treated with the light, using DCFH-DA and H2O2 sensitive fluorescent dyes.&#160;
We successfully delivered light at a range of physiologically and therapeutically relevant wavelengths and intensities, to cultured cells exposed to glutamate as a model of CNS injury. While the fluences of R/NIR-LT used in the current study did not exert an effect on ROS generated by the cultured cells, the method of light delivery is applicable to other systems including isolated mitochondria or more physiologically relevant organotypic slice culture models, and could be used to assess effects on a range of outcome measures of oxidative metabolism.

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

Non-coherent Xenon light was passed through narrow-band interference and neutral density filters to deliver light of varying wavelength and intensity to cultured cells. This protocol was used to assess the effects of red/near-infrared light therapy on production of reactive species in vitro: no effects were observed using the tested parameters.

Método para la Evaluación de los efectos de un rango de longitudes de onda e intensidades de / Terapia de luz del infrarrojo cercano Red sobre el estrés oxidativo<em&gt; In Vitro</em

Red/near-infrared light therapy (R/NIR-LT), delivered by laser or light emitting diode (LED), improves functional and morphological outcomes in a range of ...

Detection of Modified Forms of Cytosine Using Sensitive Immunohistochemistry

Methylation of cytosine bases (5-methylcytosine, 5mC) occurring in vertebrate genomes is usually associated with transcriptional silencing. 5-hydroxylmethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) are the recently discovered modified cytosine bases produced by enzymatic oxidation of 5mC, whose biological functions remain relatively obscure. A number of approaches ranging from biochemical to antibody based techniques have been employed to study the genomic distribution and global content of these modifications in various biological systems. Although some of these approaches can be useful for quantitative assessment of these modified forms of 5mC, most of these methods do not provide any spatial information regarding the distribution of these DNA modifications in different cell types, required for correct understanding of their functional roles. Here we present a highly sensitive method for immunochemical detection of the modified forms of cytosine. This method permits co-detection of these epigenetic marks with protein lineage markers and can be employed to study their nuclear localization, thus, contributing to deciphering their potential biological roles in different experimental contexts.

Herein we describe a sensitive immunochemical method for mapping the spatial distribution of 5mC oxidation derivatives based on the use of peroxidase-conjugated secondary antibodies and tyramide signal amplification.