Esta publicação vídeo foi possível graças ao financiamento do Instituto Nacional de Diabetes e Doenças Digestivas e Renais (NIDDK) para o Projeto Programa de Grant &quot;Patobiologia do Sistema Entérico&quot; DK 68055. Christopher T. Creedon foi apoiado pelo Programa de Mentoria Rochester Escolas Públicas. Agradecemos o Sr. Gary Stoltz para assistência técnica, a Sra. Kristy Zodrow para secretariado assistência e Douglas Dr. Baer, ​​de Los Gatos Research, Inc (Mountain View, CA).

1. Treinamento e habituação dos Ratos <ol><li> Antes da análise, colocar todos os ratos em câmaras de teste de 2-4 horas, com o fluxo de ar constante, a fim de se habituam-as às condições de teste. Isso reduz acentuadamente a níveis de tensão que de outra forma poderiam causar detecção aberrante de esvaziamento gástrico retardado. Tratar os ratinhos do mesmo modo que se a experiência do esvaziamento gástrico foi executado. Prepare gema de ovo (ver mais adiante) sem adição de ácido octanóico e alimentar 0,2 g a cada rato. </li><li> Repita esse processo até que os ratos são suficientemente treinados (tipicamente 2-3 vezes). Os ratos tipicamente são facilmente habituados, desde que as condições ambientais são mantidos os mesmos. </li></ol> Nota: Não habituados ratos continuam a se mover em torno de cerca de 1 hora após a transferência para a câmara, e defecar e urinar com frequência, enquanto os ratos habituados rapidamente resolver em seu novo ambiente e descansar tranquilamente. Nãote: Durante o experimento: os animais monitorar os sinais de perda de habituação, como urinar em excesso, a defecação, a falta de interesse em comer o ovo. Se este for o caso, considerar re habituating em uma câmara vazia 1-2 vezes antes de obter os dados de esvaziamento gástrico. A consistência é extremamente importante ao fazer esta experiência. Fazer as coisas exatamente da mesma maneira todas as vezes é a única maneira de obter resultados confiáveis ​​e reprodutíveis. Isto inclui fornecer o tratamento (por exemplo, insulina), a cada dia, ao mesmo tempo, não separar os ratos dos seus companheiros de gaiola, a menos que seja absolutamente necessário, os ratos em jejum e de iniciar o teste o esvaziamento gástrico ao mesmo tempo, e manipulação dos ratos da mesma maneira. 2. Preparação do Isotope contendo farinha de Teste <ol><li> Comece com pesar 5 g de gema de ovo em um tubo falcon 50 ml. Repita essas etapas cada dia experimental para preparar uma refeição de teste fresco. </li><li> Adicionar 10 ul de ácido octanóico com um Concentrção de 2 ul / g para o tubo de 50 ml Falcon contendo o ovo e misturar vigorosamente durante 1 min, com uma espátula no tubo falcon. </li><li> O ovo é então transferido para um béquer de vidro e aqueceu-se ao longo de um bico de Bunsen até que coagula e a sua consistência é adequado para fazer pequenas bolas. Isso normalmente leva cerca de 30 segundos. </li></ol> Nota: As bolas de gema de ovo deve pesar 0,2 g por mouse. Isto é importante para manter a dose cumulativa constante em todos os ratos. 3. Do início do experimento <ol><li> Uma vez treinados e prontos para o esvaziamento gástrico rápido, os ratos durante a noite (12 horas) em um metal &quot;malha inferior&quot; rack jejum para evitar coprofagia. Certifique-se de que eles têm livre acesso à água potável. Uma vez que são utilizados ratos diabéticos na experiência actual, eles não devem ser sujeitos a jejum durante mais de 16 horas. </li><li> Comece definindo-se as câmaras de esvaziamento gástrico. Use câmaras limpas e tampas que tenham sido secos ao ar. Além disso, qualquertubos que ligam as câmaras para o analisador de CO ou o fornecimento de ar 2 deve estar isenta de humidade, a água pode interferir com o sinal lido pelo analisador </li><li> Conectar as câmaras para os tubos de entrada que proporcionam um fluxo de ar constante. Em seguida, ligar os tubos de saída das câmaras para a máquina. Fechar os tubos e ligar o fluxo de ar. </li></ol> Nota: aplicar uma pequena quantidade de vaselina no final das tampas de cobertura assim que se fecham de forma fácil e estão firmemente selado. Esta vedação é necessário recolher todo o dióxido de carbono produzido pelos ratos. 4. Procedimentos Experimentais <ol><li> Comece por pesagem de cada rato. O peso corporal é uma medida da sua saúde continuada bom. Em seguida, coloque cada rato na câmara apropriada. É claro que é importante que o ar que flui para dentro das câmaras no momento. </li><li> Para iniciar a medição, permitir que os ratos para se aclimatar para as câmaras antes de ajustarção dos níveis de ar. </li><li> Uma vez que os ratos aparecem calma, o que pode demorar alguns minutos, ajustar a taxa de fluxo de ar para cada câmara de mouse. Isto pode ser diferente para cada rato. Tipicamente, o fluxo de ar é ajustada no início da experiência para se certificar de que o CO 2 exalado atinge níveis detectáveis ​​por qualquer que seja o equipamento está a ser utilizado, e para certificar-se de que o nível permanece suficientemente baixa para garantir a circulação de ar saudável. Usamos iniciais níveis de CO 2 entre 1.000 e 1.500 partes por milhão. </li><li> Se ter dificuldade com os ajustes, verificar se há vazamentos de ar. Em seguida, repita o processo para cada uma das câmaras e prestar atenção para uma nova rodada de medidas para ver se os ajustes feitos ao fluxo de ar ter corrigido o nível de CO 2. É importante para se obter uma linha de base estável da leitura antes da alimentação dos animais. Nós usamos uma máquina com um recurso de auto-calibração. Se este não é o caso de calibração deve ser verificada. </li><li> Quando isto for conseguido, administrar a refeição ovopara o primeiro registo do tempo e do rato a cada rato recebe os alimentos. </li><li> Corremos o procedimento para 4 horas para obtenção de valores suficientes para a montagem da curva 13 CO 2 para o enriquecimento de cada rato. Confira os ratos a cada 30-60 minutos para se certificar de que os níveis de CO 2 são ainda seguros para os ratos. </li><li> Preparar novas caixas contendo o alimento antes do final do teste, de modo que os ratos podem começar a comer imediatamente após o teste terminou. </li></ol>

<ol>
	<li>Yeung, C. K., McCurrie, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+to+investigate+the+inhibitory+effects+of+drugs+on+gastric+emptying+in+the+mouse+in+vivo.">A simple method to investigate the inhibitory effects of drugs on gastric emptying in the mouse in vivo.</a> J. Pharmacol. Toxicol. Methods. 45, 235-240 (2001).</li><li>Osinski, M. A., Seifert, T. R., Cox, B. F., Gintant, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+method+of+evaluation+of+drug-evoked+changes+in+gastric+emptying+in+mice.">An improved method of evaluation of drug-evoked changes in gastric emptying in mice.</a> J. Pharmacol. Toxicol. Methods. 47, 115-120 (2002).</li><li>Ghoos, Y. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+gastric+emptying+rate+of+solids+by+means+of+a+carbon-labeled+octanoic+acid+breath+test.">Measurement of gastric emptying rate of solids by means of a carbon-labeled octanoic acid breath test.</a> Gastroenterology. 104, 1640-1647 (1993).</li><li>Symonds, E., Butler, R., Omari, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+breath+tests+can+detect+alterations+in+gastric+emptying+in+the+mouse.">Noninvasive breath tests can detect alterations in gastric emptying in the mouse.</a> Eur. J. Clin. Invest. 32, 341-344 (2002).</li><li>Symonds, E. L., Butler, R. N., Omari, T. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+gastric+emptying+in+the+mouse+using+the+[13C]-octanoic+acid+breath+test.">Assessment of gastric emptying in the mouse using the [13C]-octanoic acid breath test.</a> Clin. Exp. Pharmacol. Physiol. 27, 671-675 (2000).</li><li>Verhulst, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+ghrelin+in+the+relationship+between+hyperphagia+and+accelerated+gastric+emptying+in+diabetic+mice.">Role of ghrelin in the relationship between hyperphagia and accelerated gastric emptying in diabetic mice.</a> Gastroenterology. 135, 1267-1276 (2008).</li><li>Schoonjans, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+13C-octanoic+acid+breath+test:+validation+of+a+new+noninvasive+method+of+measuring+gastric+emptying+in+rats.">The 13C-octanoic acid breath test: validation of a new noninvasive method of measuring gastric emptying in rats.</a> Neurogastroenterol. Motil. 14, 287-293 (2002).</li><li>Choi, K. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+gastric+emptying+in+nonobese+diabetic+mice.">Determination of gastric emptying in nonobese diabetic mice.</a> Am. J. Physiol. Gastrointest. Liver Physiol. 293, 1039-1045 (2007).</li><li>Atkinson, M. A., Leiter, E. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+NOD+mouse+model+of+type+1+diabetes:+as+good+as+it+gets?.">The NOD mouse model of type 1 diabetes: as good as it gets?.</a> Nat. Med. 5, 601-604 (1999).</li><li>Camilleri, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+practice.+Diabetic+gastroparesis.">Clinical practice. Diabetic gastroparesis.</a> N. Engl. J. Med. 356, 820-829 (2007).</li><li>Choi, K. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heme+oxygenase-1+protects+interstitial+cells+of+Cajal+from+oxidative+stress+and+reverses+diabetic+gastroparesis.">Heme oxygenase-1 protects interstitial cells of Cajal from oxidative stress and reverses diabetic gastroparesis.</a> Gastroenterology. 135, 2055-2064 (2008).</li><li>Kashyap, P. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+monoxide+reverses+diabetic+gastroparesis+in+NOD+mice.">Carbon monoxide reverses diabetic gastroparesis in NOD mice.</a> Am. J. Physiol. GI. G298, G1013-G1019 (2010).</li></ol>

Os autores declaram que não têm interesses conflitantes financeiros.

A técnica aqui descrita permite uma repetida e não-invasiva de medição in vivo de esvaziamento gástrico em ratos sólido. Este sistema tem a vantagem de que os animais não são retidos na câmara de medição, o que lhes permite mover-se e girar livremente. Uma vez que este é um ambiente desconhecido, os ratos ainda precisam ser treinados e habituados às câmaras de testes para evitar efeitos do estresse sobre o esvaziamento gástrico. De um modo geral, nós assumimos os dados de esvaziamento g...

Este manuscrito descreve as considerações técnicas e metodológicas envolvidas na medição não invasiva do esvaziamento gástrico em ratos. Seguindo o protocolo descrito aqui, os investigadores podem de forma fiável e reproduzível acompanhar as alterações no esvaziamento gástrico, devido ao desenvolvimento de uma doença, estudar o impacto dos agentes farmacológicos sobre o esvaziamento gástrico e seguir a resposta de esvaziamento gástrico para o tratamento de doenças subjacentes ou defeitos 6,8, 11,12. Em publicações anteriores, a aplicação de 13 C do ácido octanóico testes de respiração mostrou ser uma forma útil de medir o esvaziamento gástrico nos seres humanos e animais 3,8. Este trabalho descreve, em detalhe, os procedimentos necessários para obter dados fidedignos sobre a 8 6 para meses necessários para um estudo longitudinal de esvaziamento gástrico em ratos com diabetes. As vantagens de seguir este protocolo, quando comparada com os métodos anteriormente publicados são de que o investigador pode ser assegurado o obtaine dadosd será confiável e reprodutível. Além disso, o sistema automático de recolha e análise de amostras de gás aqui descrita aumenta o número de animais que podem ser seguidos simultaneamente em estudo. No geral, o objetivo deste trabalho é identificar os principais fatores que mantêm a habituação dos ratos para o teste e que reduzir a variabilidade nos resultados obtidos. Para a medição in vivo de esvaziamento gástrico, os ratos são alimentados durante a noite e colocados nas câmaras de ensaio de plástico transparente, com fluxo de ar constante. Depois de os ratos ficam habituados aos tubos, de linha de base exalado 13 níveis de CO 2 são determinadas e o fluxo de ar ajustado de acordo. Em seguida, administrar uma refeição de teste consistindo em gema de ovo misturado com 13 C-rotulado ácido octanóico. Porque os ratos são jejuou e treinados, eles geralmente comem a refeição de teste dentro de 2 min. A administração de ácido octanóico não é absorvido no estômago, mas será retomado no duodeno umd vai ficar metabolizada no fígado em 13 CO 2, o qual é libertado e expirado, resultando num enriquecimento de 13 CO 2 no ar circundante. As amostras de ar são recolhidos em intervalos de tempo determinados e são analisados ​​pelo analisador de isótopo de carbono. O passo limitante da velocidade, em todo este processo é o esvaziamento gástrico e a excreção pulmonar de 13 CO 2 corresponde directamente com o esvaziamento gástrico da refeição rotulados. <img src="/files/ftp_upload/50301/50301fig1.jpg" alt="Figura 1" fo:content-width="6in" fo:src="/files/ftp_upload/50301/50301fig1highres.jpg"/> Figura 1. Esquemática do aparelho de esvaziamento gástrico. Após jejum, os ratos são colocados em câmaras transparentes, permitindo-lhes mover e girar livremente. Um tubo de entrada permite que o influxo de ar fresco e constante e uma saída conduz ao analisador de isótopo para medir a 13 C a 12C em relação a respiração exalada. A câmara também tem uma porta central para fornecimento de alimentos contendo [13 C]-ácido octanóico.

<table border="1"><tbody><tr><td> NOME </td><td> EMPRESA </td><td> NÚMERO CAT </td><td> COMENTÁRIOS </td></tr><tr><td> Uma fonte de fornecimento constante de ar de fluxo, bem como a composição </td><td> central de fornecimento de ar na unidade de pesquisa </td><td></td><td></td></tr><tr><td> 130 ml câmara de amostragem que tem ar de entrada, de saída de ar, e abertura de administração de alimentos Tubos de plástico para o fornecimento de ar </td><td> Na casa construída </td><td></td><td></td></tr><tr><td> Octanóico </td><td> Cambridge Isotope Laboratories (Andover, MA) </td><td> CLM-293-1 </td><td></td></tr><tr><td> Para preparar a refeição de ovos: <ul><li> béquer pequeno </li><li> 50 tubo de plástico ml </li><li> Bico de Bunsen </li><li> ovo </li><li> espátula </li></ul></td><td> Qualquer fornecedor </td><td></td><td> Tenteser compatível com o fornecedor de ovos desde que o teor nutritivo e palatabilidade dos ovos pode afectar a ingestão e esvaziamento gástrico da refeição </td></tr><tr><td> Analisador de dióxido de carbono isótopo </td><td> Los Gatos Research Inc. (Mountain View, CA) </td><td></td><td></td></tr></tbody></table>

assessment of gastric emptying in non-obese diabetic mice using a [13c]-octanoic acid breath test

Estudos de esvaziamento gástrico em ratos têm sido limitadas pela incapacidade para acompanhar alterações gástricas esvaziamento no mesmo animal uma vez que as técnicas mais vulgarmente utilizados necessitam de matar os animais e recuperação pós-morte de 1,2 a refeição. Esta abordagem evita a estudos longitudinais para determinar alterações no esvaziamento gástrico com a idade e progressão da doença. A comummente utilizados [13 C]-octanóico teste de respiração para os seres humanos ácido 3 foi modificado para utilização em ratinhos e ratos 4-6 e 7 que anteriormente mostraram que este teste é de confiança e sensível às mudanças no esvaziamento gástrico em resposta a drogas e durante progressão da doença diabética 8. Neste vídeo de apresentação do princípio e aplicação prática deste teste modificado é explicado. Como no estudo anterior, os ratinhos NOD LTJ são usados, um modelo de diabetes do tipo 1 9. A proporção destes ratos desenvolvem os sintomas de gastroparesia, uma complicação da diabetes caracterizadas por esvaziamento gástrico retardado, sem obstrução mecânica do estômago 10. Este artigo demonstra como treinar os ratos para testes, como preparar a refeição de teste e obter 4 hr gástricas dados esvaziamento e como analisar os dados obtidos. O analisador de isótopo de carbono utilizado no presente estudo, é adequado para a amostragem automatizada de amostras de ar de até 12 ratinhos, ao mesmo tempo. Esta técnica permite o acompanhamento longitudinal de esvaziamento gástrico a partir de grupos maiores de ratos com diabetes ou outras doenças de longa duração.

Um conjunto de dados representativos a partir de três ratinhos diferentes é mostrada na Figura 2. O gráfico preto representa os pontos de dados de um rato, com o esvaziamento gástrico normal. Ela mostra a fracção de 13 C, que é recuperado no ar exalado, expressa em percentagem da dose administrada por hora expresso como uma função do tempo. A curva azul é a partir de um ratinho com um esvaziamento gástrico acelerado com um valor de meia T de 40 minutos e a curva de vermelho é de u...

Watch this Scientific Journal Video about Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a [13C]-octanoic Acid Breath Test at JoVE.com

Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a [13C]-octanoic Acid Breath Test

Determinação do esvaziamento gástrico com um não-invasivo [<sup&gt; 13</sup&gt; C]-octanóico teste de respiração ácido para gastroparesia rastreamento em camundongos NOD fêmeas LTJ.

Estudo do esvaziamento gástrico em ratos diabéticos não obesos utilizando a [<sup&gt; 13</sup&gt; C]-octanóico teste de respiração Ácido

Gastric emptying studies in mice have been limited by the inability to follow gastric emptying changes in the same animal since the most commonly used ...

assessment-gastric-emptying-non-obese-diabetic-mice-using-13c

Research

JoVE Journal

Medicine

Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a [13C]-octanoic Acid Breath Test

13.5K visualizações.  Mayo Clinic. Determinação do esvaziamento gástrico com um não-invasivo [ 13 C]-octanóico teste de respiração ácido para gastroparesia rastreamento em camundongos NOD fêmeas LTJ.

Vídeo: Assessment of Gastric Emptying in Non-obese Diabetic Mice Using a [13C]-octanoic Acid Breath Test

Making Sense of Listening: The IMAP Test Battery

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the abilities to extract and use the information encoded in the auditory signal. We refer to these as listening skills (or auditory processing AP). Deficits in these skills are associated with delayed language and literacy development, though the nature of the relevant deficits and their causal connection with these delays is hotly debated.
When a child is referred to a health professional with normal hearing and unexplained difficulties in listening, or associated delays in language or literacy development, they should ideally be assessed with a combination of psychoacoustic (AP) tests, suitable for children and for use in a clinic, together with cognitive tests to measure attention, working memory, IQ, and language skills. Such a detailed examination needs to be relatively short and within the technical capability of any suitably qualified professional. Current tests for the presence of AP deficits tend to be poorly constructed and inadequately validated within the normal population. They have little or no reference to the presenting symptoms of the child, and typically include a linguistic component. Poor performance may thus reflect problems with language rather than with AP. To assist in the assessment of children with listening difficulties, pediatric audiologists need a single, standardized child-appropriate test battery based on the use of language-free stimuli.
We present the IMAP test battery which was developed at the MRC Institute of Hearing Research to supplement tests currently used to investigate cases of suspected AP deficits. IMAP assesses a range of relevant auditory and cognitive skills and takes about one hour to complete. It has been standardized in 1500 normally-hearing children from across the UK, aged 6-11 years. Since its development, it has been successfully used in a number of large scale studies both in the UK and the USA. IMAP provides measures for separating out sensory from cognitive contributions to hearing. It further limits confounds due to procedural effects by presenting tests in a child-friendly game-format. Stimulus-generation, management of test protocols and control of test presentation is mediated by the IHR-STAR software platform. This provides a standardized methodology for a range of applications and ensures replicable procedures across testers. IHR-STAR provides a flexible, user-programmable environment that currently has additional applications for hearing screening, mapping cochlear implant electrodes, and academic research or teaching.

A test battery (IMAP) for performing an in-depth assessment of auditory and cognitive abilities contributing to listening skills is described. It is quick to administer, child-friendly and free from linguistic confounds. Stimulus generation and protocol management are controlled via a software platform (IHR-STAR) to ensure replicable procedures.

Making Sense of Listening: A bateria de testes IMAP

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the ...

Medicina

Fast and Accurate Exhaled Breath Ammonia Measurement

This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. 
Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. 
The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations.

Ammonia is an important physiologic metabolite relevant to various disease and wellness states. It is also a difficult molecule to measure in breath, which demands particular precautions be taken to obtain accurate results. Not all factors influencing ammonia are known, but progress can be difficult without accounting for these factors.

Medição Amônia ar exalado Rápido e Preciso

This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that ...

Ultrasound Assessment of Endothelial Function: A Technical Guideline of the Flow-mediated Dilation Test

Cardiovascular disease is the primary cause of mortality and a major cause of disability worldwide. The dysfunction of the vascular endothelium is a pathological condition characterized mainly by a disruption in the balance between vasodilator and vasoconstrictor substances and is proposed to play an important role in the development of atherosclerotic cardiovascular disease. Therefore, a precise evaluation of endothelial function in humans represents an important tool that could help better understand the etiology of multiple cardio-centric pathologies.
Over the past twenty-five years, many methodological approaches have been developed to provide an assessment of endothelial function in humans. Introduced in 1989, the FMD test incorporates a forearm occlusion and subsequent reactive hyperemia that promotes nitric oxide production and vasodilation of the brachial artery. The FMD test is now the most widely utilized, non-invasive, ultrasonic assessment of endothelial function in humans and has been associated with future cardiovascular events.
Although the FMD test could have clinical utility, it is a physiological assessment that has inherited several confounding factors that need to be considered. This article describes a standardized protocol for determining FMD including the recommended methodology to help minimize the physiological and technical issues and improve the precision and reproducibility of the assessment.

The flow mediated dilation (FMD) test is the most commonly utilized, non-invasive, ultrasound assessment of endothelial function in humans. Although the FMD test has been related with the prediction of future cardiovascular disease and events, it is a physiological assessment with many inherent confounding factors that need to be considered.

Avaliação ultra-sons da função endotelial: A Orientação Técnica do Teste de dilatação fluxo-mediada

Cardiovascular disease is the primary cause of mortality and a major cause of disability worldwide. The dysfunction of the vascular endothelium is a ...

Open Tracheostomy Gastric Acid Aspiration Murine Model of Acute Lung Injury Results in Maximal Acute Nonlethal Lung Injury

Acid pneumonitis is a major cause of sterile acute lung injury (ALI) in humans. Acid pneumonitis spans the clinical spectrum from asymptomatic to acute respiratory distress syndrome (ARDS), characterized by neutrophilic alveolitis, and injury to both alveolar epithelium and vascular endothelium. Clinically, ARDS is defined by acute onset of hypoxemia, bilateral patchy pulmonary infiltrates and non-cardiogenic pulmonary edema. Human studies have provided us with valuable information about the physiological and inflammatory changes in the lung caused by ARDS, which has led to various hypotheses about the underling mechanisms. Unfortunately, difficulties determining the etiology of ARDS, as well as a wide range of pathophysiology have resulted in a lack of critical information that could be useful in developing therapeutic strategies.
Translational animal models are valuable when their pathogenesis and pathophysiology accurately reproduce a concept proven in both in vitro and clinical settings. Although large animal models (e.g., sheep) share characteristics of the anatomy of human trachea-bronchial tree, murine models provide a host of other advantages including: low cost; short reproductive cycle lending itself to greater data acquisition; a well understood immunologic system; and a well characterized genome leading to the availability of a variety of gene deletion and transgenic strains. A robust model of low pH induced ARDS requires a murine ALI that targets mainly the alveolar epithelium, secondarily the vascular endothelium, as well as the small airways leading to the alveoli. Furthermore, a reproducible injury with wide differences between different injurious and non-injurious insults is important.
The murine gastric acid aspiration model presented here using hydrochloric acid employs an open tracheostomy and recreates a pathogenic scenario that reproduces the low pH pneumonitis injury in humans. Additionally, this model can be used to examine interaction of a low pH insult with other pulmonary injurious entities (e.g., food particles, pathogenic bacteria).

This protocol induces acute lung injury in a mouse that has close fidelity to the pathogenesis of acid pneumonitis observed in humans. We generate a maximal acute nonlethal low pH lung injury and account for differences in rodent-human anatomic respiratory structure using an open tracheostomy coupled with circumferential pressure release.

Abrir traqueostomia ácido gástrico aspiração Modelo murino de lesão pulmonar aguda Resultados em Maximal aguda não-letal Lung Injury

Acid pneumonitis is a major cause of sterile acute lung injury (ALI) in humans. Acid pneumonitis spans the clinical spectrum from asymptomatic to acute ...

A Blood-based Test for the Detection of ROS1 and RET Fusion Transcripts from Circulating Ribonucleic Acid Using Digital Polymerase Chain Reaction

We have developed novel methods for the isolation and characterization of tumor-derived circulating ribonucleic acid (cRNA) for blood-based liquid biopsy. Robust detection of cRNA recovered from blood represents a solution to a critical unmet need in clinical diagnostics. The test begins with the collection of whole blood into blood collection tubes containing preservatives that stabilize cRNA. Cell-free, exosomal, and platelet-associated RNA is isolated from plasma in this test system. The cRNA is reverse transcribed to complementary DNA (cDNA) and amplified using digital polymerase chain reaction (dPCR). Samples are evaluated for both the target biomarker as well as a control gene. Test validation included limit of detection, accuracy, and robustness studies with analytic samples. The method developed as a result of these studies reproducibly detect multiple fusion variants for ROS1 (C-Ros proto-oncogene 1; 8 variants) and RET (rearranged during transfection proto-oncogene; 8 variants). The sample processing workflow has been optimized so that test results can consistently be generated within 72 hours of sample receipt.

Detection of circulating ribonucleic acid (cRNA) from blood is an unmet need in clinical diagnostics. Here we describe methods that characterize cRNA from non-small cell lung cancer patients using sensitive and specific digital polymerase chain reaction. The tests meet design requirements to detect fusion variants within 72 hours.

Um sangue com base em teste para a detecção de ROS1 e RET transcrições de fusão do ácido ribonucleico, usando a reação em cadeia da polimerase Digital de circulação

We have developed novel methods for the isolation and characterization of tumor-derived circulating ribonucleic acid (cRNA) for blood-based liquid biopsy. ...

Protocol to Create Chronic Wounds in Diabetic Mice

Chronic wounds develop as a result of defective regulation in one or more complex cellular and molecular processes involved in proper healing. They impact ~6.5M people and cost ~$40B/year in the US alone. Although a significant effort has been invested in understanding how chronic wounds develop in humans, fundamental questions remain unanswered. Recently, we developed a novel mouse model for diabetic chronic wounds that have many characteristics of human chronic wounds. Using db/db-/- mice, we can generate chronic wounds by inducing high levels of oxidative stress (OS) in the wound tissue immediately after wounding, using a one-time treatment with inhibitors specific to the antioxidant enzymes catalase and glutathione peroxidase. These wounds have high levels of OS, develop biofilm naturally, become fully chronic within 20 days after treatment and can remain open more for more than 60 days. This novel model has many features of diabetic chronic wounds in humans and therefore can contribute significantly to advancing fundamental understanding of how wounds become chronic. This is a major breakthrough because chronic wounds in humans cause significant pain and distress to patients and result in amputation if unresolved. Moreover, these wounds are very expensive and time-consuming to treat, and lead to significant loss of personal income to patients. Advancements in this field of study through the use of our chronic wound model can significantly improve health care for millions who suffer under this debilitating condition. In this protocol, we describe in great detail the procedure to cause acute wounds to become chronic, which has not been done before.

Chronic wounds are developed from acute wounds on a diabetic mouse model by inducing high levels of oxidative stress after a full-thickness cutaneous wound. The wound is treated with inhibitors for catalase and glutathione peroxidase, resulting in impaired healing and biofilm development by bacteria present in the skin microbiome.

Protocolo para criar feridas crônicas em camundongos diabéticos

Chronic wounds develop as a result of defective regulation in one or more complex cellular and molecular processes involved in proper healing. They impact ...

Non-invasive Assessment of Dorsiflexor Muscle Function in Mice

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively affect skeletal muscle. This can result in a loss of muscle mass (atrophy) and/or loss of muscle quality (reduced force per unit of muscle mass), both of which are prevalent in chronic disease, muscle-specific disease, immobilization, and aging (sarcopenia). Skeletal muscle function in animals can be evaluated by a range of different tests. All tests have limitations related to the physiological testing environment, and the selection of a specific test often depends on the nature of the experiments. Here, we describe an in vivo, non-invasive technique involving a helpful and easy assessment of force frequency-curve (FFC) in mice that can be performed on the same animal over time. This permits monitoring of disease progression and/or efficacy&#160;of a potential therapeutic treatment.

Measurement of rodent skeletal muscle contractile function is a useful tool that can be used to track disease progression as well as efficacy of therapeutic intervention. We describe here the non-invasive, in vivo assessment of the dorsiflexor muscles that can be repeated over time in the same mouse.

Avaliação não-invasiva da função de músculos levantadores em ratos

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively ...

Using a Chemical Biopsy for Graft Quality Assessment

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated with an increased survival rate and greater quality of patient&#8217;s life when compared to conventional dialysis. Regrettably, transplantology suffers from a lack of reliable methods for organ quality assessment. Standard diagnostic techniques are limited to macroscopic appearance inspection or invasive tissue biopsy, which do not provide comprehensive information about the graft. The proposed protocol aims to introduce solid phase microextraction (SPME) as an ideal analytical method for comprehensive metabolomics and lipidomic analysis of all low molecular compounds present in kidneys allocated for transplantation. The small size of the SPME probe enables performance of a chemical biopsy, which enables extraction of metabolites directly from the organ without any tissue collection. The minimum invasiveness of the method permits execution of multiple analyses over time: directly after organ harvesting, during its preservation, and immediately after revascularization at the recipient&#8217;s body. It is hypothesized that the combination of this novel sampling method with a high-resolution mass spectrometer will allow for discrimination of a set of characteristic compounds that could serve as biological markers of graft quality and indicators of possible development of organ dysfunction.

The protocol presents utilization of the chemical biopsy approach followed by comprehensive metabolomic and lipidomic analysis for quality assessment of kidney grafts allocated for transplantation.

Usando uma biópsia química para avaliação da qualidade do enxerto

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated ...

A Protocol for Roux-en-Y Gastric Bypass in Rats using Linear Staplers

Roux-en-Y gastric bypass (RYGB) is commonly performed for the treatment of severe obesity and type 2 diabetes. However, the mechanism of weight loss and metabolic changes are not well understood. Multiple factors are thought to play a role, including reduced caloric intake, decreased nutrient absorption, increased satiety, the release of satiety-promoting hormones, shifts in bile acid metabolism, and alterations in the gut microbiota.
The rat RYGB model presents an ideal framework to study these mechanisms. Prior work on mouse models have had high mortality rates, ranging from 17 to 52%, limiting their adoption. Rat models demonstrate more physiologic reserve to surgical stimulus and are technically easier to adopt as they allow for the use of surgical staplers. One challenge with surgical staplers, however, is that they often leave a large gastric pouch which is not representative of RYGB in humans. 
In this protocol, we present a RYGB protocol in rats that result in a small gastric pouch using surgical staplers. Utilizing two stapler fires which remove the forestomach of the rat, we obtain a smaller gastric pouch similar to that following a typical human RYGB. Surgical stapling also results in better hemostasis than sharp division. Additionally, the forestomach of the rat does not contain any glands and its removal should not alter the physiology of RYGB.
Weight loss and metabolic changes in the RYGB cohort were significant compared to the sham cohort, with significantly lower glucose tolerance at 14 weeks. Furthermore, this protocol has an excellent survival of 88.9% after RYGB. The skills described in this protocol can be acquired without previous microsurgical experience. Once mastered, this procedure will provide a reproducible tool for studying the mechanisms and effects of RYGB.

Roux-en-Y gastric bypass (RYGB) is performed to treat obesity and diabetes. However, the mechanisms underlying RYGB's efficacy are not fully understood, and studies are limited by technical difficulty leading to high mortality in animal models. This article provides instructions on how to perform RYGB in rats with high success rates.

Um protocolo para bypass gástrico Roux-en-Y em ratos usando grampos lineares

Roux-en-Y gastric bypass (RYGB) is commonly performed for the treatment of severe obesity and type 2 diabetes. However, the mechanism of weight loss and ...

Avaliação da reserva alveolar-capilar pulmonar durante o exercício

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method

The combined single-breath measurement of the diffusing capacity of carbon monoxide (DL,CO) and nitric oxide (DL,NO) is a useful technique to measure pulmonary alveolar-capillary reserve in both healthy and patient populations. The measurement provides an estimate of the participant&#39;s ability to recruit and distend pulmonary capillaries. The method has recently been reported to exhibit a high test-retest reliability in healthy volunteers during exercise of light to moderate intensity. Of note, this technique permits up to 12 repeated maneuvers and only requires a single breath with a relatively short breath-hold time of 5 s. Representative data are provided showing the gradual changes in DL,NO and DL,CO from rest to exercise at increasing intensities&#160;of up to 60% of maximal workload. The measurement of diffusing capacity and evaluation of alveolar-capillary reserve is a useful tool to evaluate the lung&#39;s ability to respond to exercise both in the healthy population as well as in patient populations such as those with chronic lung disease.

Autor em destaque: Integrando medidas de reserva alveolar-capilar na adaptação ao exercício e estratégias terapêuticas

This protocol presents a method to assess pulmonary alveolar-capillary reserve measured by combined single-breath measurement of the diffusing capacity to carbon monoxide (DL,CO) and nitric oxide (DL,NO) during exercise. Assumptions and recommendations for using the technique during exercise form the foundation of this article.

Medida da Capacidade de Difusão Pulmonar de Gases de Teste Duplo durante o Exercício em Humanos Usando o Método de Respiração Única

The combined single-breath measurement of the diffusing capacity of carbon monoxide (DL,CO) and nitric oxide (DL,NO) is a useful technique to measure ...