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Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+compensatory+'rebound'+of+reactiveastrogliosis:+glial+fibrillary+acidic+protein+immunohistochemical+analysis+of+reactiveastrogliosis+after+a+puncture+wound+to+the+brain+of+rats+with+portocaval+anastomosis.">The compensatory 'rebound' of reactiveastrogliosis: glial fibrillary acidic protein immunohistochemical analysis of reactiveastrogliosis after a puncture wound to the brain of rats with portocaval anastomosis.</a> Acta neuropathologica. 82, 72-77 (1991).</li><li>Marchalant, Y., Rosi, S., Wenk, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-inflammatory+property+of+the+cannabinoid+agonistWIN-55212-2+in+a+rodent+model+of+chronic+brain+inflammation.">Anti-inflammatory property of the cannabinoid agonistWIN-55212-2 in a rodent model of chronic brain inflammation.</a> Neuroscience. 144, 1516-1522 (2007).</li><li>Naert, G., Ixart, G., Tapia-Arancibia, L., Givalois, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+i.c.v.+infusion+of+brainderivedneurotrophic+factor+modifies+hypothalamic-pituitary-adrenal+axis+activity,locomotor+activity+and+body+temperature+rhythms+in+adult+male+rats.">Continuous i.c.v. infusion of brainderivedneurotrophic factor modifies hypothalamic-pituitary-adrenal axis activity,locomotor activity and body temperature rhythms in adult male rats.</a> Neuroscience. 139, 779-789 (2006).</li><li>Nikkhah, G., Olsson, M., Eberhard, J., Bentlage, C., Cunningham, M. G., Bjorklund, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amicrotransplantation+approach+for+cell+suspension+grafting+in+the+rat+Parkinson+model:+adetailed+account+of+the+methodology.">Amicrotransplantation approach for cell suspension grafting in the rat Parkinson model: adetailed account of the methodology.</a> Neuroscience. 63, 57-72 (1994).</li><li>Perry, V. H., Andersson, P. B., Gordon, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophages+and+inflammation+in+the+centralnervous+system.">Macrophages and inflammation in the centralnervous system.</a> Trends Neurosci. 16, 268-273 (1993).</li><li>Radecki, D. T., Brown, L. M., Martinez, J., Teyler, T. 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Vários estudos têm demonstrado que, diminuindo o tamanho da cânula de entrega para infusões intracerebrais, trauma tecidual e insulto à barreira hemato-encefálica são reduzidos (Perry et al., 1993), a inflamação é diminuído eo atenuada imuno-resposta (Finsen et al gliose., 1991), e reativa é diminuída (Nikkhah et al., 1994). Apresentamos aqui um método para a entrega crônica de agentes neuroactive dentro do cérebro através de uma microcânula, com um diâmetro que é reduzida de 6 vezes comparado ao de cânulas de entrega convencionalmente utilizados. Temos demonstrado que este sistema oferece uma solução confiável representante ao longo do tempo e do nível de trauma localizado e gliose reativa é drasticamente reduzido. Esses estudos avaliaram uma cânula de entrega com um diâmetro da ponta final de 50 m, no entanto, diâmetros menores dica pode ser utilizada. A virtude principal de sistemas microinfusion tal é a sua capacidade de fornecer agentes para muito pequeno, metas discretas, enquanto incorrer trauma mínimo nas imediações da infusão. As microcânulas utilizados na construção do sistema de infusão que descrevemos podem ser facilmente personalizados construídos com comprimentos e diâmetros predeterminados ponta. O sistema é microinfusion concebidos de acordo com a superfície do crânio do animal, permitindo segura, a fixação de baixo perfil e excluindo a necessidade de um grande pedestal craniana. A ferida cirúrgica pode, portanto, ser facilmente suturada sobre o pedestal microinfusion simplificada, reduzindo tanto o desconforto ao animal e ao risco de infecção. Além disso, assegurar que o sistema do crânio requer menos área de superfície do crânio e, portanto, procedimentos adicionais ou subsequente pode ser realizada sem a interferência de um grande pedestal. Deve-se, no entanto, ter em conta certas considerações técnicas quando se emprega a metodologia descrita aqui. Um elevado nível de habilidade é necessária, eo processo de produção e implantação é menos eficiente do que o tempo pode ser para sistemas de infusão padrão. Por outro lado, isso pode ser superado, ou pelo menos contrabalançadas, pelo tempo (e animais) poupada pela prática de alta precisão técnica. Outra dificuldade é que enquanto a microcânula pode ser personalizado com praticamente qualquer diâmetro, uma microcânula com um lúmen pequeno pode tornar-se obstruída, seja por componentes do infusato ou por tecido encontrados durante a implantação (por exemplo, o sangue do tecido cerebral). Este risco é reduzido, mantendo a ponta microcânula umedecido (por exemplo, usando uma água ou solução salina saturada de algodão para evitar a secagem de solutos infusato) durante o processo de implantação e realizando limpa &quot;, sem sangue&quot; da cirurgia. Recomendamos que o pesquisador estabelecer um diâmetro da ponta microcânula que é apropriado para a composição particular e / ou viscosidade da solução que será carregado no MOP. Isso é facilmente conseguido através de um sistema de teste in vitro semelhante à descrita no protocolo (Fig. 4), ou simplesmente mergulhar o sistema montado em um banho de 37 ° C salina e monitoramento da composição do banho e / ou medir o volume do conteúdo MOP ao longo do tempo. A desvantagem é que a microcânula é relativamente frágil, especialmente se o seu diâmetro da ponta é muito pequeno (por exemplo, ~ 10-50 microns). Acidentalmente quebrar a microcânula durante a cirurgia geralmente requer que todo o sistema ser substituído, como a reparação ou reconstrução de que a unidade iria prolongar o tempo de cirurgia consideravelmente. Cientistas especializados em técnicas como e quem método prática exigentes raramente quebra experiência, no entanto. Na conclusão do experimento, o sistema microinfusion pode ser inspecionado para garantir que a microcânula não foi danificado e que ela manteve-se patente. O volume da bomba mini-osmótica também pode ser medido para assegurar que a quantidade adequada de agente neuroactive foi entregue; não recomendamos a reciclagem ou a reutilização das bombas, no entanto. Embora os métodos presentes foram demonstrados em ratos adultos, o uso de um sistema que reduz o trauma e requer menos área de superfície do crânio para a fixação pode ser considerado preferível em relação aos métodos convencionais para experimentos com animais pequenos, como camundongos ou ratos jovens. Embora o presente método requer um nível um pouco mais avançado de proficiência e habilidade pelo experimentador, ele oferece para aumentar a precisão, talvez, por uma ordem de magnitude, e para minimizar confunde experimental associado com trauma na região de interesse. Em nosso laboratório, descobrimos que isso se traduz em efeitos mais confiável e robusto da intervenção experimental.

A correction was made to: <a href="https://www-jove-com.remotexs.ntu.edu.sg/video/716/">Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.</a> A key reference was excluded and a revised abstract was republished.
Additional Reference: 
22. Cunningham, M.G., Ames, H.M., Donalds, R.A., &amp; Benes, F.M. Construction and implantation of a microinfusion system for sustained delivery of neuroactive agents. Journal of Neuroscience Methods 167, 213-220, doi:10.1016/j.jneumeth.2007.08.016 (2008).
Revised Abstract:
Sustained delivery of neuroactive agents is widely used in neuroscience, but poses many technical challenges. It is necessary to deliver the agent with high precision while minimizing localized trauma and inflammation. Also, the ability to customize the system to accommodate animals of different species and sizes is desirable. This video presentation demonstrates the construction of an infusion system that can be fitted to any particular research animal. The delivery microcannula diameter is approximately 10-fold smaller than most infusion cannulas presently used. This translates into enhanced accuracy and reduced trauma to the brain region under study. The delivery cannula can also be sculpted to fit the contour of the surface of the animal's skull, thereby allowing closure of the scalp incision neatly over the infusion system, precluding the need for a skull-mounted pedestal, reducing risk of infection, and ensuring a greater level of comfort to the animal. The system is assembled in an air-free environment and requires the researcher to fashion glass micropipettes with a heat source. These construction methods require special skills that are best acquired, if not in person, using video instruction. (This article is based on work first reported in J Neurosci Methods. 2008 Jan 30;167(2):213-20. Epub 2007 Aug 28.).
Original Abstract:
Experimental protocols used for chronic infusion of neuroactive agents within regions of the brain often utilize a mini-osmotic pump system. Agents are commonly delivered via a stainless steel cannula with a diameter of 0.30 mm or greater. Systems utilizing a cannula of this caliber may impose trauma to the area of interest resulting in architectural damage, thereby compromising structural integrity and normal functioning. As neuroscience inquiry becomes more sophisticated, investigation of brain structures and circuitry requires improved levels of accuracy and higher resolution. We have developed a method for the preparation and implantation of a chronic infusion system within the brain utilizing a borosilicate microcannula with a tip diameter of 50 microns. This technique reduces damage to the local environment and diminishes reactive gliosis at the site of infusion. The configuration of the microinfusion system is also able to conform to the surface of the animal's skull, precluding the need for large cranial pedestals, thus facilitating closure of the scalp incision and reducing the risk of infection. We demonstrate reliable sustained delivery of a dye having a representative molecular weight using an in vitro model and in vivo studies in rats.

A correction was made to: <a href="https://www-jove-com.remotexs.ntu.edu.sg/video/716/">Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.</a> A key reference was excluded and a revised abstract was republished.

Erratum: Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.

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construction and implantation of a microinfusion system for sustained delivery of neuroactive agents.

Protocolos experimentais usados ​​para infusão crônica de agentes neuroactive dentro das regiões do cérebro, muitas vezes utilizam um sistema de bomba de mini-osmótica. Agentes são comumente entregues através de uma cânula de aço inoxidável com um diâmetro de 0,30 mm ou maior. Sistemas utilizando uma cânula deste calibre pode impor trauma para a área de interesse, resultando em danos arquitetônicos, comprometendo a integridade estrutural e funcionamento normal. Como neurociência inquérito se torna mais sofisticada investigação, de estruturas cerebrais e circuitos exige melhores níveis de precisão e de alta resolução. Nós desenvolvemos um método para a preparação e implantação de um sistema de infusão crônica no cérebro utilizando uma microcânula borosilicato com um diâmetro da ponta de 50 microns. Esta técnica reduz os danos ao meio ambiente local e diminui gliose reativa no local da infusão. A configuração do sistema microinfusion também é capaz de estar de acordo com a superfície do crânio do animal, impedindo a necessidade de grandes pedestais cranial, facilitando o fechamento da incisão no couro cabeludo e reduzindo o risco de infecção. Demonstramos entrega sustentado confiável de um corante tendo um peso representativo molecular utilizando um modelo in vitro e in vivo em ratos.

Watch this Scientific Journal Video about Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents. at JoVE.com

Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.

Como neurociência inquérito se torna mais sofisticada investigação, de estruturas cerebrais e circuitos exige melhores níveis de precisão e de alta resolução. Nós desenvolvemos um método para a preparação e implantação de um sistema de infusão crônica no cérebro utilizando uma microcânula borosilicato com um diâmetro da ponta de 50 microns.

Construção e Implantação de um Sistema de Microinfusion para entrega Sustentada de Agentes neuroativos.

Sustained delivery of neuroactive agents is widely used in neuroscience, but poses many technical challenges. It is necessary to deliver the agent with ...

construction-implantation-microinfusion-system-for-sustained-delivery

Nanyang Technological University

Research

JoVE Journal

Biology

15.4K visualizações.  Harvard Medical School. Como neurociência inquérito se torna mais sofisticada investigação, de estruturas cerebrais e circuitos exige melhores níveis de precisão e de alta resolução. Nós desenvolvemos um método para a preparação e implantação de um sistema de infusão crônica no cérebro utilizando uma microcânula borosilicato com um diâmetro da ponta de 50 microns.

Vídeo: Construction and Implantation of a Microinfusion System for Sustained Delivery of Neuroactive Agents.

Implantation of Engineered Tissue in the Rat Heart

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in common laboratory rats or mice and these quite frequently serve as an intermediate step between bench-top experiments and large animal testing or human trials. Given that rodents provide an established, cost-effective, and physiologically-relevant model system in which to test novel combinations of scaffolding materials and cells, they are particularly well-suited for cardiovascular tissue engineering studies. Presently, we describe an open-heart surgical procedure to implant engineered tissue containing myogenic progenitor cells in the atrioventricular (AV) groove of a rat heart. These implants are intended to create an electrical conduit between the right atrium and right ventricle with the ultimate goal of providing an alternative treatment to conventional pacemaker implantation in pediatric patients with complete heart block[1]. The engineered tissue is implanted in the AV-groove by means of a thoracotomy. For our purposes, Lewis rats are anesthetized and invasively ventilated to maintain positive airway pressure during the sterile surgical procedure. The approach to the heart is performed by a right thoracotomy through an antero-lateral incision at the 5th intercostal space. The tissue construct is fixed in the AV groove using a single 7-0 Prolene suture and positioned between the right ventricle and atrium at the ventral portion of the heart. The epicardium is partially removed to allow direct contact between the recipient myocardial cells and those contained in the engineered tissue. Following implantation, the chest wall is closed in layers, any pneumothorax is evacuated, and the animal is extubated and treated with analgesic.

Here, we describe a cardiac surgical procedure to implant engineered tissue in the atrioventricular (AV)-groove of an adult Lewis rat.

Implantação de engenharia de tecidos no coração de ratos

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in ...

Biologia

The Ladder Rung Walking Task: A Scoring System and its Practical Application.

Progress in the development of animal models for/stroke, spinal cord injury, and other neurodegenerative disease requires tests of high sensitivity to elaborate distinct aspects of motor function and to determine even subtle loss of movement capacity. To enhance efficacy and resolution of testing, tests should permit qualitative and quantitative measures of motor function and be sensitive to changes in performance during recovery periods. The present study describes a new task to assess skilled walking in the rat to measure both forelimb and hindlimb function at the same time. Animals are required to walk along a horizontal ladder on which the spacing of the rungs is variable and is periodically changed. Changes in rung spacing prevent animals from learning the absolute and relative location of the rungs and so minimize the ability of the animals to compensate for impairments through learning. In addition, changing the spacing between the rungs allows the test to be used repeatedly in long-term studies. Methods are described for both quantitative and qualitative description of both fore- and hindlimb performance, including limb placing, stepping, co-ordination. Furthermore, use of compensatory strategies is indicated by missteps or compensatory steps in response to another limb&#x2019;s misplacement. 

The ladder rung walking task is a new test to assess skilled walking and measure both forelimb and hindlimb placing, stepping, and inter-limb co-ordination.

O Ladder Rung Walking Tarefa: um sistema de pontuação e sua aplicação prática.

Progress in the development of animal models for/stroke, spinal cord injury, and other neurodegenerative disease requires tests of high sensitivity to ...

High Speed Droplet-based Delivery System for Passive Pumping in Microfluidic Devices

A novel microfluidic system has been developed that uses the phenomenon of passive pumping along with a user controlled droplet based fluid delivery system. Passive pumping is the phenomenon by which surface tension induced pressure differences drive fluid movement in closed channels. The automated fluid delivery system consists of a set of voltage controlled valves with micro-nozzles connected to a fluid reservoir and a control system. These voltage controlled valves offer a volumetrically precise way to deliver fluid droplets to the inlet of a microfluidic device in a high frequency manner. Based on the  dimensions demonstrated in the current study example, the system is capable of flowing 4 milliliters per minute (through a 2.2mm by 260um cross-sectional channel). Based on these same channel dimensions, fluid exchange of a point inside the channel can be achieved in as little as eight milliseconds. It is observed that there is interplay between momentum of the system (imparted by a combination of the droplets created by the valves and the fluid velocity in the channel), and the surface tension of the liquid. Where momentum provides velocity to the fluid flow (or vice-versa), equilibration of surface tension at the inlet provides a sudden stop to any flow. This sudden stop allows the user to control the flow characteristics of the channel and opens the door for a variety of biological applications, ranging anywhere from reagent delivery to drug-cell studies. It is also observed that when nozzles are aimed at the inlet at shallow angles, the droplet momentum can cause additional interesting fluid phenomena, such as mixing of multiple droplets in the inlet.

A novel microfluidic system has been developed using the phenomenon of passive pumping and a user controlled fluid delivery system. This microfluidic system has the potential to be used in a wide variety of biological applications given its low cost, ease of use, volumetric precision, high speed, repeatability and automation.

High Speed ​​Delivery System Droplet-based para Passive Bombeamento em dispositivos microfluídicos

A novel microfluidic system has been developed that uses the phenomenon of passive pumping along with a user controlled droplet based fluid delivery ...

Visualization of Caenorhabditis elegans Cuticular Structures Using the Lipophilic Vital Dye DiI

The cuticle of C. elegans is a highly resistant structure that surrounds the exterior of the animal1-4. The cuticle not only protects the animal from the environment, but also determines body shape and plays a role in motility4-6. Several layers secreted by epidermal cells comprise the cuticle, including an outermost lipid layer7.
Circumferential ridges in the cuticle called annuli pattern the length of the animal and are present during all stages of development8. Alae are longitudinal ridges that are present during specific stages of development, including L1, dauer, and adult stages2,9. Mutations in genes that affect cuticular collagen organization can alter cuticular structure and animal body morphology5,6,10,11. While cuticular imaging using compound microscopy with DIC optics is possible, current methods that highlight cuticular structures include fluorescent transgene expression12, antibody staining13, and electron microscopy1. Labeled wheat germ agglutinin (WGA) has also been used to visualize cuticular glycoproteins, but is limited in resolving finer cuticular structures14. Staining of cuticular surface using fluorescent dye has been observed, but never characterized in detail15. We present a method to visualize cuticle in live C. elegans using the red fluorescent lipophilic dye DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate), which is commonly used in C. elegans to visualize environmentally exposed neurons. This optimized protocol for DiI staining is a simple, robust method for high resolution fluorescent visualization of annuli, alae, vulva, male tail, and hermaphrodite tail spike in C. elegans.

Visualization of Caenorhabditis elegans Cuticular Structures Using the Lipophilic Vital Dye DiI

We present a method to visualize cuticle in live C. elegans using the red fluorescent lipophilic dye DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate), which is commonly used in C. elegans to visualize environmentally exposed neurons. With this optimized protocol, alae and annular cuticular structures are stained by DiI and observed using compound microscopy.

Visualização de Caenorhabditis elegans Estruturas cutícula Usando o Dye lipofílicos Vital, DII

The cuticle of C. elegans is a highly resistant structure that surrounds the exterior of the animal1-4. The cuticle not only protects the animal from the ...

A System for ex vivo Culturing of Embryonic Pancreas

The pancreas controls vital functions of our body, including the production of digestive enzymes and regulation of blood sugar levels1. Although in the past decade many studies have contributed to a solid foundation for understanding pancreatic organogenesis, important gaps persist in our knowledge of early pancreas formation2. A complete understanding of these early events will provide insight into the development of this organ, but also into incurable diseases that target the pancreas, such as diabetes or pancreatic cancer. Finally, this information will generate a blueprint for developing cell-replacement therapies in the context of diabetes.
 During embryogenesis, the pancreas originates from distinct embryonic outgrowths of the dorsal and ventral foregut endoderm at embryonic day (E) 9.5 in the mouse embryo3,4. Both outgrowths evaginate into the surrounding mesenchyme as solid epithelial buds, which undergo proliferation, branching and differentiation to generate a fully mature organ2,5,6. Recent evidences have suggested that growth and differentiation of pancreatic cell lineages, including the insulin-producing &beta;-cells, depends on proper tissue-architecture, epithelial remodeling and cell positioning within the branching pancreatic epithelium7,8. However, how branching morphogenesis occurs and is coordinated with proliferation and differentiation in the pancreas is largely unknown. This is in part due to the fact that current knowledge about these developmental processes has relied almost exclusively on analysis of fixed specimens, while morphogenetic events are highly dynamic.
 Here, we report a method for dissecting and culturing mouse embryonic pancreatic buds ex vivo on glass bottom dishes, which allow direct visualization of the developing pancreas (Figure 1). This culture system is ideally devised for confocal laser scanning microscopy and, in particular, live-cell imaging. Pancreatic explants can be prepared not only from wild-type mouse embryos, but also from genetically engineered mouse strains (e.g. transgenic or knockout), allowing real-time studies of mutant phenotypes. Moreover, this ex vivo culture system is valuable to study the effects of chemical compounds on pancreatic development, enabling to obtain quantitative data about proliferation and growth, elongation, branching, tubulogenesis and differentiation. In conclusion, the development of an ex vivo pancreatic explant culture method combined with high-resolution imaging provides a strong platform for observing morphogenetic and differentiation events as they occur within the developing mouse embryo.

A System for ex vivo Culturing of Embryonic Pancreas

Here, we describe a method for isolation, culture and manipulation of mouse embryonic pancreas. This represents an excellent ex vivo system for studying various aspects of pancreatic development, including morphogenesis, differentiation and growth. Pancreatic bud explants can be cultured for several days and used in a range of different applications, including whole-mount immunofluorescence and live imaging.

Um Sistema de<em&gt; Ex vivo</em&gt; A cultura de Pâncreas embrionárias

The pancreas controls vital functions of our body,  including the production of digestive enzymes and regulation of blood sugar  levels1. Although in the ...

A High-throughput Method for Measurement of Glomerular Filtration Rate in Conscious Mice

The measurement of glomerular filtration rate (GFR) is the gold standard in kidney function assessment. Currently, investigators determine GFR by measuring the level of the endogenous biomarker creatinine or exogenously applied radioactive labeled inulin (3H or 14C). Creatinine has the substantial drawback that proximal tubular secretion accounts for ~50% of total renal creatinine excretion and therefore creatinine is not a reliable GFR marker. Depending on the experiment performed, inulin clearance can be determined by an intravenous single bolus injection or continuous infusion (intravenous or osmotic minipump). Both approaches require the collection of plasma or plasma and urine, respectively. Other drawbacks of radioactive labeled inulin include usage of isotopes, time consuming surgical preparation of the animals, and the requirement of a terminal experiment. Here we describe a method which uses a single bolus injection of fluorescein isothiocyanate-(FITC) labeled inulin and the measurement of its fluorescence in 1-2 &mu;l of diluted plasma. By applying a two-compartment model, with 8 blood collections per mouse, it is possible to measure GFR in up to 24 mice per day using a special work-flow protocol. This method only requires brief isoflurane anesthesia with all the blood samples being collected in a non-restrained and awake mouse. Another advantage is that it is possible to follow mice over a period of several months and treatments (i.e. doing paired experiments with dietary changes or drug applications). We hope that this technique of measuring GFR is useful to other investigators studying mouse kidney function and will replace less accurate methods of estimating kidney function, such as plasma creatinine and blood urea nitrogen.

Measurement of glomerular filtration rate (GFR) is the gold standard for kidney function assessment. Here we describe a high-throughput method which allows the determination of GFR in conscious mice by using a single bolus injection, determination of fluorescein isothiocyanate (FITC)-inulin in plasma and calculation of GFR by a two-phase exponential decay model.

Um Método de alta capacidade para medição de Taxa de filtração glomerular em ratos conscientes

The measurement of  glomerular filtration rate (GFR) is the gold standard in kidney function  assessment. Currently, investigators determine GFR by ...

Phosphopeptide Analysis of Rodent Epididymal Spermatozoa

Spermatozoa are quite unique amongst cell types. Although produced in the testis, both nuclear gene transcription and translation are switched off once the pre-cursor round cell begins to elongate and differentiate into what is morphologically recognized as a spermatozoon. However, the spermatozoon is very immature, having no ability for motility or egg recognition. Both of these events occur once the spermatozoa transit a secondary organ known as the epididymis. During the ~12 day passage that it takes for a sperm cell to pass through the epididymis, post-translational modifications of existing proteins play a pivotal role in the maturation of the cell. One major facet of such is protein phosphorylation. In order to characterize phosphorylation events taking place during sperm maturation, both pure sperm cell populations and pre-fractionation of phosphopeptides must be established. Using back flushing techniques, a method for the isolation of pure spermatozoa of high quality and yield from the distal or caudal epididymides is outlined. The steps for solubilization, digestion, and pre-fractionation of sperm phosphopeptides through TiO2 affinity chromatography are explained. Once isolated, phosphopeptides can be injected into MS to identify both protein phosphorylation events on specific amino acid residues and quantify the levels of phosphorylation taking place during the sperm maturation processes.

Proteomic analysis of any cell type is highly dependent on both purity and pre-fractionation of the starting material in order to de-complexify the sample prior to liquid chromatography mass spectrometry (MS). By using back-flushing techniques, pure spermatozoa can be obtained from rodents. Following digestion, phosphopeptides can be enriched using TiO2.

Fosfopéptido Análise de Rodent epidídimo Espermatozóides

Spermatozoa are quite unique amongst cell types. Although produced in the testis, both nuclear gene transcription and translation are switched off once ...

Subcloning Plus Insertion (SPI) - A Novel Recombineering Method for the Rapid Construction of Gene Targeting Vectors

Gene targeting refers to the precise modification of a genetic locus using homologous recombination. The generation of novel cell lines and transgenic mouse models using this method necessitates the construction of a &#8216;targeting&#8217; vector, which contains homologous DNA sequences to the target gene, and has for many years been a limiting step in the process. Vector construction can be performed in vivo in Escherichia coli cells using homologous recombination mediated by phage recombinases using a technique termed recombineering. Recombineering is the preferred technique to subclone the long homology sequences (>4kb) and various targeting elements including selection markers that are required to mediate efficient allelic exchange between a targeting vector and its cognate genomic locus. Typical recombineering protocols follow an iterative scheme of step-wise integration of the targeting elements and require intermediate purification and transformation steps. Here, we present a novel recombineering methodology of vector assembly using a multiplex approach. Plasmid gap repair is performed by the simultaneous capture of genomic sequence from mouse Bacterial Artificial Chromosome libraries and the insertion of dual bacterial and mammalian selection markers. This subcloning plus insertion method is highly efficient and yields a majority of correct recombinants. We present data for the construction of different types of conditional gene knockout, or knock-in, vectors and BAC reporter vectors that have been constructed using this method. SPI vector construction greatly extends the repertoire of the recombineering toolbox and provides a simple, rapid and cost-effective method of constructing these highly complex vectors.

Subcloning Plus Insertion SPI - A Novel Recombineering Method for the Rapid Construction of Gene Targeting Vectors

Gene targeting methodologies can be used to generate transgenic mice with knockout, knock-in and tagged alleles. Here, we describe an improved method of recombineering in E. coli, that we term &#8216;subcloning plus insertion&#8217;, which can be used to generate custom gene targeting vectors rapidly.

Subclonagem Além disso Inserção (SPI) - Um Método recombineering Novel para a construção rápida de Gene Segmentação Vetores

Gene targeting refers to the precise modification of a genetic locus using homologous recombination. The generation of novel cell lines and transgenic ...

Single Cell Collection of Trophoblast Cells in Peri-implantation Stage Human Embryos

Human implantation, the apposition and adhesion to the uterine surface epithelia and subsequent invasion of the blastocyst into the maternal decidua, is a critical yet enigmatic biological event that has been historically difficult to study due to technical and ethical limitations. Implantation is initiated by the development of the trophectoderm to early trophoblast and subsequent differentiation into distinct trophoblast sublineages. Aberrant early trophoblast differentiation may lead to implantation failure, placental pathologies, fetal abnormalities, and miscarriage. Recently, methods have been developed to allow human embryos to grow until day 13 post-fertilization in vitro in the absence of maternal tissues, a time-period that encompasses the implantation period in humans. This has given researchers the opportunity to investigate human implantation and recapitulate the dynamics of trophoblast differentiation during this critical period without confounding maternal influences and avoiding inherent obstacles to study early embryo differentiation events in vivo. To characterize different trophoblast sublineages during implantation, we have adopted existing two-dimensional (2D) extended culture methods and developed a procedure to enzymatically digest and isolate different types of trophoblast cells for downstream assays. Embryos cultured in 2D conditions have a relatively flattened morphology and may be suboptimal in modeling in vivo three-dimensional (3D) embryonic architectures. However, trophoblast differentiation seems to be less affected as demonstrated by anticipated morphology and gene expression changes over the course of extended culture. Different trophoblast sublineages, including cytotrophoblast, syncytiotrophoblast and migratory trophoblast can be separated by size, location, and temporal emergence, and used for further characterization or experimentation. Investigation of these early trophoblast cells may be instrumental in understanding human implantation, treating common placental pathologies, and mitigating the incidence of pregnancy loss.

Here, we describe a method for warming vitrified human blastocysts, culturing them through the implantation period in vitro, digesting them into single cells and collecting early trophoblast cells for further investigation.

Coleção celular única de células trophoblastos em embriões humanos de estágio de peri-implantação

Human implantation, the apposition and adhesion to the uterine surface epithelia and subsequent invasion of the blastocyst into the maternal decidua, is a ...

Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds

Staphylococcus aureus expresses virulence factors to trigger its internalization into eukaryote cells and to survive inside different subcellular compartments. This paper describes an enzyme protection assay to study the extent of S. aureus internalization and its intracellular survival in adherent non-professional phagocytic cells (NPPCs) as well as the intracellular efficacy of antimicrobial compounds. NPPCs are grown in a multi-well plate until they reach 100% confluence. S. aureus cultures are grown overnight in cell culture medium. The bacterial suspension is diluted according to the number of cells per well to inoculate the cells at a controlled multiplicity of infection. Inoculated cells are incubated for 2 h to allow the bacteria to be internalized by the NPPCs, following which lysostaphin is added to the culture medium to selectively kill extracellular bacteria. Lysostaphin is present in the culture medium for the rest of the experiment. 
At this point, the infected cells could be incubated with antimicrobial compounds to assess their intracellular activities against S. aureus. Next, the cells are washed three times to remove the drugs, and intracellular S. aureus load is then quantified by culturing on agar plates. Alternatively, for studying staphylococcal virulence factors involved in intracellular survival and cell toxicity, lysostaphin could be inactivated with proteinase K to eliminate the need for washing steps. This tip improves the reliability of the intracellular bacterial load quantification, especially if cells tend to detach from the culture plate when they become heavily infected because of the multiplication of intracellular S. aureus. These protocols can be used with virtually all types of adherent NPPCs and with 3D cell culture models such as organoids.

Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds

This protocol aims to describe how to study the extent of Staphylococcus aureus internalization and its ability to survive inside the human host cell, as well as the intracellular efficacy of antimicrobial compounds.

Ensaio de proteção de enzimas melhorada para estudar a internalização staphylococcus aureus e eficácia intracelular de compostos antimicrobianos

Construção e Implantação de um Sistema de Microinfusion para entrega Sustentada de Agentes neuroativos.

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O Ladder Rung Walking Tarefa: um sistema de pontuação e sua aplicação prática.

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Um Método de alta capacidade para medição de Taxa de filtração glomerular em ratos conscientes

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