Assuntos
Humanos , Queratinócitos/ultraestrutura , Junções Intercelulares/fisiologia , Desmossomos/fisiologia , Junções Intercelulares/fisiologia , Queratinócitos/química , Desmossomos/química , Desmossomos/ultraestrutura , Integrinas/química , Integrinas/fisiologia , Moléculas de Adesão Celular/fisiologia , Imunoglobulinas/química , Penfigoide Bolhoso , Programas de AutoavaliaçãoAssuntos
Humanos , Desmossomos/fisiologia , Junções Intercelulares/fisiologia , Queratinócitos/ultraestrutura , Desmossomos/química , Desmossomos/ultraestrutura , Imunoglobulinas/química , Integrinas/química , Integrinas/fisiologia , Junções Intercelulares/fisiologia , Queratinócitos/química , Moléculas de Adesão Celular/fisiologia , Penfigoide Bolhoso , Programas de AutoavaliaçãoRESUMO
Laser-assisted microvascular anastomoses can be performed more quickly than sutured anastomoses, yet manifest similar patency rates and tensile strength. This study was undertaken to determine if in vitro laser-assisted microvascular anastomoses could be created between human adult arteries (anterior tibial arteries), human placental arteries, and expanded polytetrafluoroethylene microconduits. A CO2 laser was applied in single or continuous bursts with a matrix of variables encompassing power P = 80 to 160 mW, spot size SS = 150 to 500 microns, and exposure time EXP = 1.0-second continuous exposure (n = 2 each composite setting). The endpoints measured to assess the ability to laser-weld vessels were morphologic appearance by scanning electron microscopy and bursting strength. Scanning electron microscopy revealed apparent fusion of human placental arteries and human adult arteries to expanded polytetrafluoroethylene microconduits at settings of P = 130 mW, SS = 300 microns, and EXP = 1.0 second, though bursting pressure at all settings was less than 10 mmHg. Laser-assisted microvascular anastomoses of human placental artery to human placental artery and human adult artery to human adult artery were successful at this setting, though bursting pressures of anastomoses incorporating placental vessels were significantly weaker than those created with adult tissue. The relative weakness of laser-assisted microvascular anastomoses incorporating placental arteries might be explained by qualitative or quantitative differences in vessel wall collagen, as seen in fetal tissue, and deserves further characterization.
Assuntos
Artérias/cirurgia , Prótese Vascular , Terapia a Laser , Microcirurgia/métodos , Politetrafluoretileno , Adulto , Anastomose Cirúrgica , Artérias/ultraestrutura , Fenômenos Biomecânicos , Humanos , Técnicas In Vitro , Microcirculação/cirurgia , Microscopia Eletrônica de Varredura , Placenta/irrigação sanguíneaRESUMO
The propensity for platelets to bind at a native vessel anastomosis is thought to be related to subendothelial exposure, the presence of suture material, and local flow disturbances. By using an artificial microvascular graft to artificial microvascular graft anastomosis model that mimics the geometry and topography of a native microvascular anastomosis but which eliminates the endothelial and subendothelial contributions, the influence of the normal anastomotic configuration alone on initial platelet deposition was measured. Anastomotic and immediate downstream platelet deposition was not augmented by the presence of the anastomotic configuration alone. This suggests that the enhanced initial platelet deposition in the region of a native vessel microanastomosis is primarily related to the presence of injured endothelium and exposed subendothelium rather than to flow disturbances.
Assuntos
Anastomose Cirúrgica/métodos , Prótese Vascular , Microcirurgia/métodos , Agregação Plaquetária/fisiologia , Politetrafluoretileno , Combinação de Medicamentos , Hemostáticos/química , Humanos , Radioisótopos de Índio , Microscopia Eletrônica de Varredura , Modelos Cardiovasculares , Palmitatos/química , Adesividade Plaquetária/fisiologia , Contagem de Plaquetas , Politetrafluoretileno/química , Reologia , Propriedades de Superfície , Ceras/químicaRESUMO
Vasodilation of small blood vessels is controlled in part by the endothelium-derived relaxing factor (EDRF), which also inhibits platelet adhesion. Methylene blue (MB), which is occasionally applied directly to blood vessels during microsurgery to provide orientation and prevent torsion, is an irreversible inhibitor of the effects of endothelium-derived relaxing factor and may thereby augment both vasospasm and platelet responses. We have investigated the effects of the extravascular adventitial application of methylene blue on platelet deposition to human placental arteries (HPA) in the presence and absence of surgically induced vasospasm. A trend toward increased platelet deposition to human placental arteries was seen in each group but did not reach significance. The degree of platelet deposition to control human placental arteries suggests that the effects of methylene blue on platelet deposition may be dwarfed by the effects of surgical trauma and ischemia.
Assuntos
Artérias/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Azul de Metileno/farmacologia , Óxido Nítrico/antagonistas & inibidores , Vasoconstrição/efeitos dos fármacos , Administração Tópica , Etidocaína/farmacologia , Feminino , Humanos , Técnicas In Vitro , Azul de Metileno/administração & dosagem , Placenta/irrigação sanguínea , GravidezRESUMO
The mechanism of platelet thrombus growth on an artificial surface is incompletely understood. While glycoprotein (GP)Ib and GPIIb/IIIa are required for normal attachment and thrombus formation on subendothelium, their roles in platelet deposition to artificial surfaces remain unclear. Using selected platelet inhibitors (aspirin [ASA], low molecular weight dextran, monoclonal antibodies 10E5 [v GPIIb/IIIa], and 6D1 [GPIb]) we examined the mechanism of platelet deposition to polyethylene (PE) surfaces under steady laminar and oscillatory flow conditions. Polyethylene-100 (PE-100) tubes (0.86 mm internal diameter) were perfused under steady laminar flow with citrated human whole blood reconstituted with 111indium-labeled platelets at 312 seconds-1 shear rate in the presence and absence of platelet inhibitors. The effect of oscillatory flow on platelet deposition was examined in a microwell system using 3/16-inch diameter discs of National Heart, Lung, and Blood Institute primary reference PE as the test surface. ASA and dextran did not significantly (P greater than .05) inhibit platelet deposition in laminar flow (not tested in oscillatory). Antibody 10E5 was a potent inhibitor (laminar less than 1%, P less than .0001, oscillatory less than 1.6%, P less than .01) of platelet deposition in both systems, and in this case, true adhesion (first attached layer) was blocked. Antibody 6D1 unexpectedly inhibited 70% of platelet deposition (P less than .01) in steady laminar flow and 56.5% in oscillatory flow (P less than .01). Scanning electron microscopy demonstrated platelets atop platelets in the controls, rare platelets in the 10E5 group, and a patchy monolayer of platelets in the 6D1 group. Transmission electron microscopy of cross-sections confirmed these observations. We conclude that the adhesion of the first platelet layer to an artificial surface requires GPIIb/IIIa. The data also suggest that GPIb is required for the development of the second layer in vertical platelet thrombus growth.
Assuntos
Anticorpos Monoclonais/farmacologia , Plaquetas/fisiologia , Adesividade Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Glicoproteínas da Membrana de Plaquetas/fisiologia , Difosfato de Adenosina/sangue , Trifosfato de Adenosina/sangue , Aspirina/farmacologia , Plaquetas/citologia , Plaquetas/efeitos dos fármacos , Humanos , Técnicas In Vitro , L-Lactato Desidrogenase/sangue , Perfusão/instrumentação , Perfusão/métodos , Adesividade Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Glicoproteínas da Membrana de Plaquetas/imunologiaRESUMO
Rapid occlusion of artificial microvascular grafts (AMGs; less than or equal to 2-mm diameter) by platelet-rich thrombi prevents the clinical use of AMGs in cardiac, vascular, and plastic surgery. Since present antiplatelet agents are unable to assure AMG patency, we have studied the role of specific platelet membrane-glycoprotein blockade on platelet retention by AMGs. In a customized in vitro perfusion chamber, retention on polytetrafluoroethylene (PTFE) AMGs (1.0-mm i.d.) of indium-111-labeled platelets in human whole blood was measured in the presence and absence of inhibitors. Specific blockade of platelet membrane glycoprotein (Gp) IIb/IIIa was achieved using monoclonal antibody 10E5 (10 micrograms/ml) and the peptide GRGDS (Gly-Arg-Gly-Asp-Ser, 0.75 mM). These inhibited 98% and 35%, respectively, of platelet retention under circumstances in which aspirin (7 mM) and dextran (4 mg/ml) inhibited 19% and 18%, respectively, of platelet retention. Nonspecific immunoglobulin G F(ab')2 (10 micrograms/ml) and nonspecific peptide (GGDA; Gly-Gly-Asp-Ala, 0.75 mM), used as control reagents, were ineffective in this setting. Monoclonal antibody 6D1 (10 micrograms/ml), which blocks platelet membrane GpIb, prevented 82% of platelet retention on PTFE. These doses of 10E5 and GRGDS completely inhibited platelet aggregation in response to 20 microM ADP, and the dose of 6D1 completely inhibited ristocetin-induced platelet agglutination. The aspirin dose prevented the second phase of ADP-induced aggregation. These data indicate that not only does initial platelet adhesion to PTFE require GpIIb/IIIa but also that GpIb plays a significant role in the early stages of platelet retention on PTFE AMGs.
Assuntos
Anticorpos Monoclonais/farmacologia , Plaquetas/fisiologia , Prótese Vascular , Fibrinogênio/fisiologia , Microcirculação , Glicoproteínas da Membrana de Plaquetas/fisiologia , Difosfato de Adenosina/farmacologia , Aspirina/farmacologia , Dextranos/farmacologia , Humanos , Microscopia Eletrônica de Varredura , Fragmentos de Peptídeos/farmacologia , Adesividade Plaquetária , Agregação Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Glicoproteínas da Membrana de Plaquetas/antagonistas & inibidores , Glicoproteínas da Membrana de Plaquetas/imunologia , Politetrafluoretileno , Ristocetina/farmacologiaRESUMO
Presentamos el caso de una paciente de 36 años con una dermatosis generalizada vésicoampollar, pruriginosa, con características clínico-evolutivas de PP. Se realizaron estudios histopatológicos, de IFD e IFI que confirmaron el diagnóstico. Ponemos especial énfasis en lo poco frecuente de la entidad, su diagnóstico diferencial con la enfermedad de D³hring y el valor de las técnicas de inmunofluorescencia y microscopía inmunoelectrónica para la correcta ubicación nosológica de la enfermedad (AU)
Assuntos
Adulto , Humanos , Feminino , Penfigoide Bolhoso/diagnóstico , Penfigoide Bolhoso/tratamento farmacológico , Penfigoide Bolhoso/patologia , Metilprednisolona/uso terapêutico , Dapsona/uso terapêutico , Dexametasona/uso terapêutico , Imunofluorescência , Dermatite Herpetiforme/diagnóstico , Diagnóstico Diferencial , Imunofluorescência , Microscopia ImunoeletrônicaRESUMO
Presentamos el caso de una paciente de 36 años con una dermatosis generalizada vésicoampollar, pruriginosa, con características clínico-evolutivas de PP. Se realizaron estudios histopatológicos, de IFD e IFI que confirmaron el diagnóstico. Ponemos especial énfasis en lo poco frecuente de la entidad, su diagnóstico diferencial con la enfermedad de Dühring y el valor de las técnicas de inmunofluorescencia y microscopía inmunoelectrónica para la correcta ubicación nosológica de la enfermedad
Assuntos
Adulto , Humanos , Feminino , Penfigoide Bolhoso/diagnóstico , Penfigoide Bolhoso/tratamento farmacológico , Penfigoide Bolhoso/patologia , Dapsona/uso terapêutico , Dermatite Herpetiforme/diagnóstico , Dexametasona/uso terapêutico , Diagnóstico Diferencial , Imunofluorescência , Metilprednisolona/uso terapêutico , Microscopia ImunoeletrônicaRESUMO
Presentamos una casuística de 42 pacientes con dermatomiositis incluyendo dos casos de la forma infantil, y realizamos una revisión del tema poniendo especial énfasis en las variaciones acometidad en los últimos 30 años en relación a formas clínicas de presentación, manifestaciones cutáneas de la enfermedad, tratamiento y evolución
Assuntos
Criança , Pessoa de Meia-Idade , Humanos , Feminino , DermatomiositeRESUMO
Presentamos una casuística de 42 pacientes con dermatomiositis incluyendo dos casos de la forma infantil, y realizamos una revisión del tema poniendo especial énfasis en las variaciones acometidad en los últimos 30 años en relación a formas clínicas de presentación, manifestaciones cutáneas de la enfermedad, tratamiento y evolución (AU)