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1.
Nat Immunol ; 21(1): 86-100, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31844327

RESUMO

By developing a high-density murine immunophenotyping platform compatible with high-throughput genetic screening, we have established profound contributions of genetics and structure to immune variation (http://www.immunophenotype.org). Specifically, high-throughput phenotyping of 530 unique mouse gene knockouts identified 140 monogenic 'hits', of which most had no previous immunologic association. Furthermore, hits were collectively enriched in genes for which humans show poor tolerance to loss of function. The immunophenotyping platform also exposed dense correlation networks linking immune parameters with each other and with specific physiologic traits. Such linkages limit freedom of movement for individual immune parameters, thereby imposing genetically regulated 'immunologic structures', the integrity of which was associated with immunocompetence. Hence, we provide an expanded genetic resource and structural perspective for understanding and monitoring immune variation in health and disease.


Assuntos
Infecções por Enterobacteriaceae/imunologia , Variação Genética/genética , Ensaios de Triagem em Larga Escala/métodos , Imunofenotipagem/métodos , Infecções por Salmonella/imunologia , Animais , Citrobacter/imunologia , Infecções por Enterobacteriaceae/microbiologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Salmonella/imunologia , Infecções por Salmonella/microbiologia
2.
Cell ; 154(2): 452-64, 2013 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-23870131

RESUMO

Mutations in whole organisms are powerful ways of interrogating gene function in a realistic context. We describe a program, the Sanger Institute Mouse Genetics Project, that provides a step toward the aim of knocking out all genes and screening each line for a broad range of traits. We found that hitherto unpublished genes were as likely to reveal phenotypes as known genes, suggesting that novel genes represent a rich resource for investigating the molecular basis of disease. We found many unexpected phenotypes detected only because we screened for them, emphasizing the value of screening all mutants for a wide range of traits. Haploinsufficiency and pleiotropy were both surprisingly common. Forty-two percent of genes were essential for viability, and these were less likely to have a paralog and more likely to contribute to a protein complex than other genes. Phenotypic data and more than 900 mutants are openly available for further analysis. PAPERCLIP:


Assuntos
Técnicas Genéticas , Camundongos Knockout , Fenótipo , Animais , Doença/genética , Modelos Animais de Doenças , Feminino , Genes Essenciais , Estudo de Associação Genômica Ampla , Masculino , Camundongos
3.
PLoS Biol ; 13(5): e1002151, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25992600

RESUMO

The Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines were developed to address the lack of reproducibility in biomedical animal studies and improve the communication of research findings. While intended to guide the preparation of peer-reviewed manuscripts, the principles of transparent reporting are also fundamental for in vivo databases. Here, we describe the benefits and challenges of applying the guidelines for the International Mouse Phenotyping Consortium (IMPC), whose goal is to produce and phenotype 20,000 knockout mouse strains in a reproducible manner across ten research centres. In addition to ensuring the transparency and reproducibility of the IMPC, the solutions to the challenges of applying the ARRIVE guidelines in the context of IMPC will provide a resource to help guide similar initiatives in the future.


Assuntos
Experimentação Animal/normas , Bases de Dados como Assunto , Guias como Assunto , Fenótipo , Animais , Camundongos
5.
Nucleic Acids Res ; 42(Database issue): D802-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24194600

RESUMO

The International Mouse Phenotyping Consortium (IMPC) web portal (http://www.mousephenotype.org) provides the biomedical community with a unified point of access to mutant mice and rich collection of related emerging and existing mouse phenotype data. IMPC mouse clinics worldwide follow rigorous highly structured and standardized protocols for the experimentation, collection and dissemination of data. Dedicated 'data wranglers' work with each phenotyping center to collate data and perform quality control of data. An automated statistical analysis pipeline has been developed to identify knockout strains with a significant change in the phenotype parameters. Annotation with biomedical ontologies allows biologists and clinicians to easily find mouse strains with phenotypic traits relevant to their research. Data integration with other resources will provide insights into mammalian gene function and human disease. As phenotype data become available for every gene in the mouse, the IMPC web portal will become an invaluable tool for researchers studying the genetic contributions of genes to human diseases.


Assuntos
Bases de Dados Genéticas , Camundongos Knockout , Fenótipo , Animais , Ontologias Biológicas , Internet , Camundongos
6.
Mamm Genome ; 26(9-10): 467-81, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26208973

RESUMO

Large-scale systemic mouse phenotyping, as performed by mouse clinics for more than a decade, requires thousands of mice from a multitude of different mutant lines to be bred, individually tracked and subjected to phenotyping procedures according to a standardised schedule. All these efforts are typically organised in overlapping projects, running in parallel. In terms of logistics, data capture, data analysis, result visualisation and reporting, new challenges have emerged from such projects. These challenges could hardly be met with traditional methods such as pen & paper colony management, spreadsheet-based data management and manual data analysis. Hence, different Laboratory Information Management Systems (LIMS) have been developed in mouse clinics to facilitate or even enable mouse and data management in the described order of magnitude. This review shows that general principles of LIMS can be empirically deduced from LIMS used by different mouse clinics, although these have evolved differently. Supported by LIMS descriptions and lessons learned from seven mouse clinics, this review also shows that the unique LIMS environment in a particular facility strongly influences strategic LIMS decisions and LIMS development. As a major conclusion, this review states that there is no universal LIMS for the mouse research domain that fits all requirements. Still, empirically deduced general LIMS principles can serve as a master decision support template, which is provided as a hands-on tool for mouse research facilities looking for a LIMS.


Assuntos
Pesquisa Biomédica , Sistemas de Informação em Laboratório Clínico , Software , Animais , Camundongos
8.
Mamm Genome ; 23(9-10): 641-52, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22991088

RESUMO

The International Mouse Phenotyping Consortium (IMPC) (http://www.mousephenotype.org) will reveal the pleiotropic functions of every gene in the mouse genome and uncover the wider role of genetic loci within diverse biological systems. Comprehensive informatics solutions are vital to ensuring that this vast array of data is captured in a standardised manner and made accessible to the scientific community for interrogation and analysis. Here we review the existing EuroPhenome and WTSI phenotype informatics systems and the IKMC portal, and present plans for extending these systems and lessons learned to the development of a robust IMPC informatics infrastructure.


Assuntos
Camundongos/genética , Fenótipo , Animais , Internacionalidade
9.
Mamm Genome ; 23(9-10): 600-10, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22961258

RESUMO

Two large-scale phenotyping efforts, the European Mouse Disease Clinic (EUMODIC) and the Wellcome Trust Sanger Institute Mouse Genetics Project (SANGER-MGP), started during the late 2000s with the aim to deliver a comprehensive assessment of phenotypes or to screen for robust indicators of diseases in mouse mutants. They both took advantage of available mouse mutant lines but predominantly of the embryonic stem (ES) cells resources derived from the European Conditional Mouse Mutagenesis programme (EUCOMM) and the Knockout Mouse Project (KOMP) to produce and study 799 mouse models that were systematically analysed with a comprehensive set of physiological and behavioural paradigms. They captured more than 400 variables and an additional panel of metadata describing the conditions of the tests. All the data are now available through EuroPhenome database (www.europhenome.org) and the WTSI mouse portal (http://www.sanger.ac.uk/mouseportal/), and the corresponding mouse lines are available through the European Mouse Mutant Archive (EMMA), the International Knockout Mouse Consortium (IKMC), or the Knockout Mouse Project (KOMP) Repository. Overall conclusions from both studies converged, with at least one phenotype scored in at least 80% of the mutant lines. In addition, 57% of the lines were viable, 13% subviable, 30% embryonic lethal, and 7% displayed fertility impairments. These efforts provide an important underpinning for a future global programme that will undertake the complete functional annotation of the mammalian genome in the mouse model.


Assuntos
Genoma , Camundongos/genética , Animais , Europa (Continente) , Células Germinativas , Mutação , Fenótipo
10.
Nucleic Acids Res ; 38(Database issue): D577-85, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19933761

RESUMO

The broad aim of biomedical science in the postgenomic era is to link genomic and phenotype information to allow deeper understanding of the processes leading from genomic changes to altered phenotype and disease. The EuroPhenome project (http://www.EuroPhenome.org) is a comprehensive resource for raw and annotated high-throughput phenotyping data arising from projects such as EUMODIC. EUMODIC is gathering data from the EMPReSSslim pipeline (http://www.empress.har.mrc.ac.uk/) which is performed on inbred mouse strains and knock-out lines arising from the EUCOMM project. The EuroPhenome interface allows the user to access the data via the phenotype or genotype. It also allows the user to access the data in a variety of ways, including graphical display, statistical analysis and access to the raw data via web services. The raw phenotyping data captured in EuroPhenome is annotated by an annotation pipeline which automatically identifies statistically different mutants from the appropriate baseline and assigns ontology terms for that specific test. Mutant phenotypes can be quickly identified using two EuroPhenome tools: PhenoMap, a graphical representation of statistically relevant phenotypes, and mining for a mutant using ontology terms. To assist with data definition and cross-database comparisons, phenotype data is annotated using combinations of terms from biological ontologies.


Assuntos
Biologia Computacional/métodos , Bases de Dados Genéticas , Bases de Dados de Proteínas , Animais , Biologia Computacional/tendências , Armazenamento e Recuperação da Informação/métodos , Internet , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Knockout , Fenótipo , Linguagens de Programação , Estrutura Terciária de Proteína , Software
11.
Proc Natl Acad Sci U S A ; 105(27): 9290-5, 2008 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-18579772

RESUMO

Transposon systems are widely used for generating mutations in various model organisms. PiggyBac (PB) has recently been shown to transpose efficiently in the mouse germ line and other mammalian cell lines. To facilitate PB's application in mammalian genetics, we characterized the properties of the PB transposon in mouse embryonic stem (ES) cells. We first measured the transposition efficiencies of PB transposon in mouse embryonic stem cells. We next constructed a PB/SB hybrid transposon to compare PB and Sleeping Beauty (SB) transposon systems and demonstrated that PB transposition was inhibited by DNA methylation. The excision and reintegration rates of a single PB from two independent genomic loci were measured and its ability to mutate genes with gene trap cassettes was tested. We examined PB's integration site distribution in the mouse genome and found that PB transposition exhibited local hopping. The comprehensive information from this study should facilitate further exploration of the potential of PB and SB DNA transposons in mammalian genetics.


Assuntos
Cromossomos de Mamíferos/metabolismo , Elementos de DNA Transponíveis/genética , Células-Tronco Embrionárias/metabolismo , Animais , Sequência de Bases , Metilação de DNA , Genoma/genética , Camundongos , Mutagênese , Mutagênicos , Proteínas/genética , RNA não Traduzido , Transposases/metabolismo
12.
Cancer Immunol Res ; 8(12): 1568-1582, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32999002

RESUMO

The immunosuppressive tumor microenvironment constitutes a significant hurdle to immune checkpoint inhibitor responses. Both soluble factors and specialized immune cells, such as regulatory T cells (Treg), are key components of active intratumoral immunosuppression. Inducible costimulatory receptor (ICOS) can be highly expressed in the tumor microenvironment, especially on immunosuppressive Treg, suggesting that it represents a relevant target for preferential depletion of these cells. Here, we performed immune profiling of samples from tumor-bearing mice and patients with cancer to demonstrate differential expression of ICOS in immune T-cell subsets in different tissues. ICOS expression was higher on intratumoral Treg than on effector CD8 T cells. In addition, by immunizing an Icos knockout transgenic mouse line expressing antibodies with human variable domains, we selected a fully human IgG1 antibody called KY1044 that bound ICOS from different species. We showed that KY1044 induced sustained depletion of ICOShigh T cells but was also associated with increased secretion of proinflammatory cytokines from ICOSlow effector T cells (Teff). In syngeneic mouse tumor models, KY1044 depleted ICOShigh Treg and increased the intratumoral TEff:Treg ratio, resulting in increased secretion of IFNγ and TNFα by TEff cells. KY1044 demonstrated monotherapy antitumor efficacy and improved anti-PD-L1 efficacy. In summary, we demonstrated that using KY1044, one can exploit the differential expression of ICOS on T-cell subtypes to improve the intratumoral immune contexture and restore an antitumor immune response.


Assuntos
Anticorpos Monoclonais/farmacologia , Proteína Coestimuladora de Linfócitos T Induzíveis/metabolismo , Linfócitos T Reguladores/imunologia , Microambiente Tumoral/efeitos dos fármacos , Animais , Anticorpos Monoclonais/imunologia , Antígeno B7-H1/imunologia , Linhagem Celular Tumoral , Citocinas/metabolismo , Feminino , Humanos , Tolerância Imunológica/efeitos dos fármacos , Proteína Coestimuladora de Linfócitos T Induzíveis/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
13.
Nucleic Acids Res ; 35(8): e64, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17426124

RESUMO

Functional analysis of mammalian genes in vivo is primarily achieved through analysing knockout mice. Now that the sequencing of several mammalian genomes has been completed, understanding functions of all the genes represents the next major challenge in the post-genome era. Generation of knockout mutant mice has currently been achieved by many research groups but only by making individual knockouts, one by one. New technological advances and the refinements of existing technologies are critical for genome-wide targeted mutagenesis in the mouse. We describe here new recombineering reagents and protocols that enable recombineering to be carried out in a 96-well format. Consequently, we are able to construct 96 conditional knockout targeting vectors simultaneously. Our new recombineering system makes it a reality to generate large numbers of precisely engineered DNA constructs for functional genomics studies.


Assuntos
Bacteriófago lambda/genética , Marcação de Genes/métodos , Vetores Genéticos , Camundongos Knockout , Recombinação Genética , Animais , Proteínas de Homeodomínio/genética , Camundongos , Plasmídeos/genética , Fatores de Transcrição
14.
J Nanosci Nanotechnol ; 16(5): 4993-8, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27483858

RESUMO

The transparent conductive oxide layers are of great interest in recent researches because of their tunable properties which avail them to be used in varieties of applications. The important and most widely used TCO materials such as ITO and AZO films were prepared with three different layer thicknesses using DC sputtering system. The structural, optical and electrical characteristics of both ITO and AZO samples were analyzed and compared to reveal thickness dependent tunable properties of TCO materials. The maximum transmittance of 99.5% was obtained for AZO films at 600-700 nm wavelength range. The resistivity of ITO films was 200 times lesser than that of AZO films. The internal and external quantum efficiencies of ITO devices increased with increasing layer thickness whereas this situation was just opposite in case of AZO devices. The optical and electrical properties of ITO samples were found easily adjustable by changing layer thickness as compared to AZO samples. This study explores the strong association between the layer thickness and the properties of TCO films. This would be useful to extend the applications boundary of TCO materials.

15.
Sci Rep ; 5: 9256, 2015 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-25787933

RESUMO

Periodical nanocone-arrays were employed in an emitter region for high efficient Si solar cells. Conventional wet-etching process was performed to form the nanocone-arrays for a large area, which spontaneously provides the graded doping features for a selective emitter. This enables to lower the electrical contact resistance and enhances the carrier collection due to the high electric field distribution through a nanocone. Optically, the convex-shaped nanocones efficiently reduce light-reflection and the incident light is effectively focused into Si via nanocone structure, resulting in an extremely improved the carrier collection performances. This nanocone-arrayed selective emitter simultaneously satisfies optical and electrical improvement. We report the record high efficiency of 16.3% for the periodically nanoscale patterned emitter Si solar cell.

16.
J Thorac Cardiovasc Surg ; 125(2): 391-9, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12579110

RESUMO

OBJECTIVE: We tested whether the CardioClasp device (CardioClasp, Inc, Cincinnati, Ohio), a non-blood contact device, would improve left ventricular contractility by acutely reshaping the left ventricle and reducing left ventricular wall stress. METHODS: In dogs (n = 6) 4 weeks of ventricular pacing (210-240 ppm) induced severe heart failure. Left ventricular function was evaluated before and after placement of the CardioClasp device, which uses 2 indenting bars to reshape the left ventricle. Hemodynamics, echocardiography, and Sonometrics crystals dimension (Sonometrics Corporation, London, Ontario, Canada) were measured at steady state and during inferior vena caval occlusion. RESULTS: The CardioClasp device decreased the left ventricular end-diastolic anterior-posterior dimension by 22.8% +/- 1.9%, decreased left ventricular wall stress from 97.3 +/- 22.8 to 67.2 +/- 7.7 g/cm(2) (P =.003), and increased the fractional area of contraction from 21.3% +/- 10.5% to 31.3% +/- 18.1% (P =.002). The clasp did not alter left ventricular end-diastolic pressure, left ventricular pressure, left ventricular dP/dt, or cardiac output. With the CardioClasp device, the slope of the end-systolic pressure-volume relationship was increased from 1.87 +/- 0.47 to 3.22 +/- 1.55 mm Hg/mL (P =.02), the slope of preload recruitable stroke work versus end-diastolic volume was increased from 28.4 +/- 11.0 to 44.1 +/- 23.5 mm Hg (P =.02), and the slope of maximum dP/dt versus end-diastolic volume was increased from 10.6 +/- 4.6 to 18.6 +/- 7.4 mm Hg x s(-1) x mL(-1) (P =.01). The CardioClasp device increased the slope of the end-systolic pressure-volume relationship by 68.0% +/- 21.7%, the slope of preload recruitable stroke work versus end-diastolic volume by 50.7% +/- 18.1%, and the slope of maximum dP/dt versus end-diastolic volume by 85.7% +/- 28.9%. CONCLUSIONS: The CardioClasp device decreased left ventricular wall stress and increased the fractional area of contraction by reshaping the left ventricle. The CardioClasp device was able to maintain cardiac output and arterial pressure. The clasp increased global left ventricular contractility by increasing the slope of the end-systolic pressure-volume relationship, the slope of preload recruitable stroke work versus end-diastolic volume, and the slope of maximum dP/dt versus end-diastolic volume. In patients with heart failure, the CardioClasp device might be effective for clinical application.


Assuntos
Cardiomiopatia Dilatada/complicações , Modelos Animais de Doenças , Insuficiência Cardíaca/complicações , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/cirurgia , Volume Sistólico , Função Ventricular Esquerda , Pressão Ventricular , Remodelação Ventricular , Animais , Estimulação Cardíaca Artificial , Constrição , Cães , Ecocardiografia , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/fisiopatologia , Teste de Materiais
17.
J Thorac Cardiovasc Surg ; 126(1): 56-65, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12878939

RESUMO

OBJECTIVE: If the geometric distortion during dilated heart failure could be corrected, the tension on the myocytes would be decreased, thereby leading to an improvement in left ventricular systolic function. We tested the effects of the CardioClasp (CardioClasp Inc, Pine Brook, NJ), a left ventricular reshaping device, on the failing heart, and our empirical data were compared with computationally derived data. METHODS: Heart failure was induced by 4-week rapid cardiac pacing. At the terminal experiment, an isolated failing heart preparation (isovolumic contraction, n = 5) or an intact failing heart in vivo (n = 7) was used. The effects of the reshaping device on left ventricular performance were assessed by the slopes (Ees) of the left ventricular end-systolic pressure-volume relations, hemodynamics, and echocardiograph before and after placing the CardioClasp on the heart. The change in Ees as the result of left ventricular reshaping was also estimated from computed theoretical analysis and compared with empirical data. RESULTS: There was a significant change in left ventricular dimension after placing the CardioClasp on the heart. In isolated heart preparation, Ees significantly increased from 1.40 +/- 0.44 mm Hg/mL to 2.42 +/- 0.63 mm Hg/mL after placing the device on the heart but returned to the baseline level (1.46 +/- 0.27 mm Hg) after removing it. Left ventricular developed pressure and left ventricular fractional area shortening were significantly increased as the result of left ventricular reshaping. Ees derived from computed theoretical analysis was highly correlated with confirming empirical data. CONCLUSIONS: The CardioClasp can reshape the left ventricle and improve left ventricular systolic performance in failing hearts.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Contração Miocárdica/fisiologia , Função Ventricular Esquerda/fisiologia , Remodelação Ventricular/fisiologia , Animais , Estimulação Cardíaca Artificial/efeitos adversos , Modelos Animais de Doenças , Cães , Ecocardiografia , Insuficiência Cardíaca/etiologia , Ventrículos do Coração/fisiopatologia , Modelos Cardiovasculares , Modelos Teóricos , Valor Preditivo dos Testes , Estatística como Assunto , Volume Sistólico/fisiologia , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/fisiopatologia
18.
J Heart Lung Transplant ; 22(9): 1046-53, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12957615

RESUMO

BACKGROUND: We tested whether the CardioClasp, a passive non-blood-contacting device could decrease excessive geometric burden in dilated cardiomyopathy and improve left ventricular systolic function and contractility by reshaping the left ventricle (LV) and by decreasing LV wall stress (LVWS) without decreasing arterial blood pressure. METHODS: In mongrel dogs (n = 6, the early group; n = 6, the chronic group; 25-27 kg), 4 weeks of rapid right ventricular pacing (210 to 240 bpm) induced dilated cardiomyopathy with heart failure. In the early group, we used hemodynamic data and echocardiography to evaluate LV systolic function immediately after placing the CardioClasp device. In the chronic group, we also evaluated LV systolic function immediately after placing the device on dilated hearts and then left the device in place for 30 days. At the end of 30 days, before explantation of the device, we again assessed LV systolic function. We measured fractional area of contraction (FAC), LVWS, and hemodynamic data in both groups. RESULTS: In the early group, use of the CardioClasp device decreased the LV end-diastolic anterior-to-posterior dimension by 27.8% +/- 2.6% at implantation (p < 0.05). In the chronic group, use of the CardioClasp decreased the LV end-diastolic anterior-to-posterior dimension by 19.4% +/- 2.0% at implantation (p < 0.05) and by 22.0% +/- 3.10% at explantation (p < 0.05). Use of the CardioClasp did not alter LV end-diastolic and peak pressure, LV dP/dts, or cardiac output at implantation or at explantation. In the early group, use of the CardioClasp decreased the LVWS by 43.4% +/- 3.1% at implantation (p < 0.05). In the chronic group, LVWS decreased by 28.8% +/- 2.1% at implantation (p < 0.05) and by 43.3% +/- 5.2% at explantation (p < 0.05). In the early group, FAC increased significantly, by 28.9% +/- 7.8% at implantation (p < 0.05). In the chronic group, FAC increased significantly, by 18% +/- 12% at implantation (p < 0.05) and by 19% +/- 12% at explantation (p < 0.05). CONCLUSIONS: As expected, use of the CardioClasp device increased FAC and decreased LVWS by reshaping the LV. Use of the CardioClasp device maintained cardiac output and arterial pressure. In 30-day experiments, the increased FAC and decreased LVWS were maintained at explantation.


Assuntos
Cardiomiopatia Dilatada/terapia , Coração Auxiliar , Remodelação Ventricular , Animais , Cardiomiopatia Dilatada/cirurgia , Modelos Animais de Doenças , Cães , Ecocardiografia , Hemodinâmica
19.
ASAIO J ; 48(1): 62-70, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-11814099

RESUMO

Reliable tissue fixation is of fundamental importance to the successful development of muscle powered motor prostheses. This report describes a series of canine implant trials used to develop stable tissue-device interface mechanisms. Muscle pumps were fitted with prototype tendon and chest wall anchoring schemes and secured to the ribs and humeral insertion of latissimus dorsi (LD) muscles. LD stimulation was initiated 1 week postimplantation and continued throughout the implant period to stress these fixation sites. Design modification and implant testing were continued until both muscle and chest wall attachment points were found to be stable. Chest wall fixation was best achieved using perforated metallic plates wired to the ribs, as opposed to bone screws or wire mesh, which were subject to degradation. Direct attachment of the native tendon by means of spiked clamping plates proved ineffective. Stable muscle attachment was ultimately achieved by replacing the humeral tendon with an artificial substitute formed from fine polyester fibers gathered into 6-8 bundles and sewn into the LD insertion. Braided into a single cord, these fibers were fixed to the device by means of spiked clamping plates. Based on these findings, we conclude that perforated anchor plates and multifibrous artificial tendons can function as effective tissue-device interface mechanisms.


Assuntos
Cardiomioplastia/métodos , Músculo Esquelético/metabolismo , Músculo Esquelético/cirurgia , Implantação de Prótese/métodos , Tendões/cirurgia , Animais , Órgãos Artificiais , Placas Ósseas , Cães , Metabolismo Energético , Próteses e Implantes , Costelas/cirurgia , Suturas , Tórax
20.
ASAIO J ; 48(3): 253-9, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12058999

RESUMO

In dilated heart failure, geometric distortions place an extra load on the myocardial cells. If this extra burden can be eliminated, the myocardial wall stress would decrease leading to improved systolic ventricular performance. In a dilated heart failure model, we wanted to see whether the CardioClasp (which uses two indenting bars to reshape the left ventricle [LV] as two widely communicating "lobes" of reduced radius) could improve systolic performance by passively reshaping the LV and reducing the wall stress. In mongrel dogs (n = 7; 25-27 kg), rapid ventricular pacing (210 ppm 1st week to 240 ppm 4th week) induced dilated heart failure. After 4 weeks, LV performance was evaluated at baseline and with the CardioClasp by measuring LV end-diastolic and peak LV systolic pressure, LV +dP/dt, LV -dP/ dt, and cardiac output. With the Clasp on, LV wall stress was reduced to 58.6+/-3.5 from 108.3+/-8.2 g/cm2. The fractional area of contraction (FAC) with the Clasp on (28.4+/-4.4) was significantly increased (p < 0.05) from baseline (20.8+/-4.6) and consistent with improved systolic performance. Cardiac output, LV peak systolic and end-diastolic pressures, and regional myocardial blood flow were unaltered. The Clasp was able to acutely reshape the left ventricle, while preserving the contractile mass, and reduced the tension on the myocardial cells and increased the fractional area of contraction without decreasing the systolic blood pressure.


Assuntos
Insuficiência Cardíaca/terapia , Coração Auxiliar , Hipertrofia Ventricular Esquerda/terapia , Animais , Cães , Função Ventricular Esquerda
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