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1.
Sci Adv ; 8(28): eabn2330, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35857502

RESUMO

The physical causes of organ malformation remain largely unclear in most cases due to a lack of information on tissue/cell dynamics. Here, we address this issue by considering onset of cyclopia in sonic hedgehog (SHH)-inhibited chick embryos. We show that ventral forebrain-specific self-organization ability driven by SHH-dependent polarized patterns in cell shape, phosphorylated myosin localization, and collective cell motion promotes optic vesicle elongation during normal development. Stress loading tests revealed that these polarized dynamics result from mechanical responses. In particular, stress and active tissue deformation satisfy orthogonality, defining an SHH-regulated morphogenetic law. Without SHH signaling, cells cannot detect the direction of stress and move randomly, leading to insufficient optic vesicle elongation and consequently a cyclopia phenotype. Since polarized tissue/cell dynamics are common in organogenesis, cell disorientation caused by loss of mechanosensation could be a pathogenic mechanism for other malformations.

2.
Cell Rep ; 30(11): 3889-3903.e5, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32187557

RESUMO

Despite extensive study, the morphogenetic mechanisms of heart looping remain controversial because of a lack of information concerning precise tissue-level deformation and the quantitative relationship between tissue and cellular dynamics; this lack of information causes difficulties in evaluating previously proposed models. To overcome these limitations, we perform four-dimensional (4D) high-resolution imaging to reconstruct a tissue deformation map, which reveals that, at the tissue scale, initial heart looping is achieved by left-right (LR) asymmetry in the direction of deformation within the myocardial tube. We further identify F-actin-dependent directional cell rearrangement in the right myocardium as a major contributor to LR asymmetric tissue deformation. Our findings demonstrate that heart looping involves dynamic and intrinsic cellular behaviors within the tubular tissue and provide a significantly different viewpoint from current models that are based on LR asymmetry of growth and/or stress at the tube boundaries. Finally, we propose a minimally sufficient model for initial heart looping that is also supported by mechanical simulations.


Assuntos
Coração/anatomia & histologia , Imageamento Tridimensional , Estresse Mecânico , Actinas/metabolismo , Pontos de Referência Anatômicos , Animais , Anisotropia , Padronização Corporal , Divisão Celular , Forma Celular , Tamanho Celular , Galinhas , Simulação por Computador , Modelos Anatômicos , Miocárdio/citologia , Polimerização , Imagem com Lapso de Tempo
3.
Comput Methods Biomech Biomed Engin ; 18(11): 1143-1159, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24506461

RESUMO

In this study, for predicting arterial function and pathogenesis from a mechanical viewpoint, we develop a continuum mechanical model of an arterial wall that embodies residual and active stresses following a traditional anisotropic passive constitutive law. The residual and active stresses are incorporated into finite element methods based on a two-field variational principle described in the Lagrangian form. The linearisation of nonlinear weak-form equations derived from this variational principle is then described for developing an original finite element algorithm. Numerical simulations reveal the following: (i) residual stresses lead to a reduction in stress gradient regardless of the magnitude of external load; (ii) active stresses help homogenise stress distribution under physiological external load, but this homogeneity collapses under pathological external load; (iii) when residual and active stresses act together, the effect of the residual stresses is relatively obscured by that of the active stresses. We conclude that residual stresses have minor but persistent mechanical effects on the arterial wall under both physiological and pathological external loads; active stresses play an important role in the physiological functions and pathogenesis of arteries, and the mechanical effect of residual stresses is dependent on the presence/absence of active stresses.

4.
Gastrointest Endosc ; 73(4): 777-84, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21272874

RESUMO

BACKGROUND: EMR is an accepted treatment for early esophageal carcinoma. However, resection of a large mucosal area often causes postoperative esophageal stricture. OBJECTIVE: To investigate the efficacy of autologous adipose tissue-derived stromal cells (ADSCs) for prevention of stricture formation after EMR in dogs. DESIGN: Animal study. SETTING: University research center. INTERVENTION: Ten beagle dogs were randomized into a control group and an ADSCs-injected (ADSC) group. The ADSCs were isolated from autologous adipose tissue. Immediately after circumferential esophageal EMR, about 5 × 10(6) ADSCs suspended in 8 mL of phosphate-buffered saline solution were injected endoscopically into the residual submucosa of the ADSC group, whereas the control group received only 8 mL of phosphate-buffered saline solution. MAIN OUTCOME MEASUREMENTS: Dysphagia score, weight loss, rate of mucosal constriction, and histologic assessments. RESULTS: In the control and ADSC groups, the median dysphagia scores were 4 and 1 (P < .043), the mean degrees of mucosal constriction were 75.7% and 45.3% (P < .008), and the numbers of nascent microvessels in the submucosal layer were 7.4 and 16.2 per unit area (P = .007), respectively. Atrophy and fibrosis of the muscularis propria layer were observed in the control group. LIMITATIONS: Animal study, small sample size. CONCLUSION: Injection therapy with autologous ADSCs suppresses constriction of the esophageal mucosa and improves clinical symptoms after circumferential EMR in this canine model.


Assuntos
Tecido Adiposo/citologia , Estenose Esofágica/prevenção & controle , Esofagectomia/efeitos adversos , Esôfago/cirurgia , Mucosa Intestinal/cirurgia , Células Estromais/transplante , Tecido Adiposo/transplante , Animais , Cães , Estenose Esofágica/etiologia , Esofagectomia/métodos , Feminino , Seguimentos , Injeções , Masculino , Complicações Pós-Operatórias , Transplante Autólogo/métodos , Resultado do Tratamento
5.
World J Gastrointest Endosc ; 2(8): 288-92, 2010 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-21160628

RESUMO

AIM: To evaluate the efficacy of retrograde observation of the esophagus, pharynx, larynx and lingual root. METHODS: With the beagle dog under anesthesia, the anterior wall of the stomach was fixed on the abdominal wall in a similar way to percutaneous endoscopic gastrostomy. The gastrointestinal scope was inserted via a 12 mm laparoscopic port for subsequent retrograde observation from stomach to the oral cavity. RESULTS: With this technique, direct observation of gastric cardia was possible without restriction. The cervical esophagus was dilated well, also allowing clear observation of the hypopharyngo-esophageal junction. If the tongue was manually pulled out forward, observation of the lingual root was possible. CONCLUSION: This procedure is easy and effective for pre-treatment evaluation of the feasibility of endoscopic resection in cases of superficial carcinoma of head and neck.

6.
Gen Thorac Cardiovasc Surg ; 57(4): 211-3, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19367455

RESUMO

Hypothermia and immunosuppressive drugs may promote surgical wound infection. We successfully performed an emergency total arch replacement with mild hypothermia and selective cerebral perfusion for a renal transplant recipient. The postoperative course was almost uneventful without any surgical site infection.


Assuntos
Aorta Torácica/cirurgia , Aneurisma da Aorta Torácica/cirurgia , Implante de Prótese Vascular/métodos , Isquemia Encefálica/prevenção & controle , Hipotermia Induzida , Transplante de Rim , Antibioticoprofilaxia , Aneurisma da Aorta Torácica/diagnóstico , Circulação Cerebrovascular , Humanos , Masculino , Pessoa de Meia-Idade , Infecção da Ferida Cirúrgica/prevenção & controle
7.
J Artif Organs ; 9(4): 259-62, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17171405

RESUMO

We report the case of a mitral Carpentier-Edwards pericardial bioprosthesis that was explanted from a 43-year-old female patient because of structural valve deterioration 16 years following implantation. Upon removal, the prosthesis was found to be discolored and all leaflets were stiff and hard, showing extensive calcification, pannus overgrowth, leaflet hematoma, and multiple disruptions. One leaflet presented a wavy free margin due to commissural disruptions, leading to incomplete cusp coaptation. The accumulated physical symptoms of the patient were consistent with these findings.


Assuntos
Bioprótese , Próteses Valvulares Cardíacas , Valva Mitral , Adulto , Remoção de Dispositivo , Ecocardiografia Doppler , Feminino , Implante de Prótese de Valva Cardíaca , Humanos , Insuficiência da Valva Mitral/congênito , Insuficiência da Valva Mitral/cirurgia , Falha de Prótese , Reoperação
8.
J Artif Organs ; 8(3): 214-6, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16235040

RESUMO

We report the case of an 89-year-old patient suffering from endocarditis with septicemia caused by a growth on a pacemaker lead. The entire pacemaker system was successfully removed using cardiopulmonary bypass. Although the patient was an octogenarian in poor condition with a systemic infection, an aggressive operation with careful perioperative management gave a good clinical result. As far as we know, this is the oldest patient in whom a pacemaker system has been removed using cardiopulmonary bypass.


Assuntos
Ponte Cardiopulmonar , Remoção de Dispositivo , Endocardite/cirurgia , Marca-Passo Artificial/efeitos adversos , Infecções Relacionadas à Prótese/cirurgia , Infecções Estafilocócicas/cirurgia , Idoso de 80 Anos ou mais , Endocardite/etiologia , Humanos , Masculino
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