RESUMO
Mast cells (MCs) are cells of hematopoietic origin that normally reside in mucosal tissues, often near epithelial cells, glands, smooth muscle cells, and nerves. Best known for their contributions to pathology during IgE-associated disorders such as food allergy, asthma, and anaphylaxis, MCs are also thought to mediate IgE-associated effector functions during certain parasite infections. However, various MC populations also can be activated to express functional programs--such as secreting preformed and/or newly synthesized biologically active products--in response to encounters with products derived from diverse pathogens, other host cells (including leukocytes and structural cells), damaged tissue, or the activation of the complement or coagulation systems, as well as by signals derived from the external environment (including animal toxins, plant products, and physical agents). In this review, we will discuss evidence suggesting that MCs can perform diverse effector and immunoregulatory roles that contribute to homeostasis or pathology in mucosal tissues.
Assuntos
Anafilaxia/imunologia , Asma/imunologia , Hipersensibilidade Alimentar/imunologia , Imunidade nas Mucosas , Enteropatias Parasitárias/imunologia , Mastócitos/imunologia , Anafilaxia/genética , Anafilaxia/patologia , Animais , Asma/genética , Asma/patologia , Citocinas/genética , Citocinas/imunologia , Hipersensibilidade Alimentar/genética , Hipersensibilidade Alimentar/patologia , Expressão Gênica , Humanos , Imunoglobulina E/genética , Imunoglobulina E/imunologia , Enteropatias Parasitárias/genética , Enteropatias Parasitárias/patologia , Mastócitos/patologia , Camundongos , Mucosa/imunologia , Mucosa/patologia , Especificidade da EspécieRESUMO
The purpose of this study was to describe and compare the muscle firing patterns of the muscles controlling the ankle during running. Fine-wire electrodes monitored the activity of the gastrocnemius, soleus, peroneus brevis, tibialis posterior, and tibialis anterior muscles during 3 paces of running. High-speed film was used to synchronize the electromyographic data with the phases of running. The subjects were 15 recreational and competitive runners who were injury-free. There were 3 significant findings. First, the firing patterns of all of the posterior muscles demonstrated peak activity during midstance phase. Thus, these muscles were contracting in an eccentric fashion to control ankle dorsiflexion as the center of gravity passed over the ankle. Second, the tibialis anterior muscle fired above the fatigue threshold for 85% of the time. This may account for the high number of fatigue-related injuries to the tibialis anterior muscle seen in runners. Third, there was a significant increase of activity in the peroneus brevis muscle as the pace increased. This indicates the importance of training this muscle when pace is increased. Using this information, a sport-specific effective and efficient exercise program for runners can be developed.
Assuntos
Tornozelo/fisiologia , Músculos/fisiologia , Corrida/fisiologia , Adulto , Eletromiografia , Feminino , Marcha/fisiologia , Humanos , Masculino , Contração MuscularRESUMO
The mastering of the clinical skills is of utmost importance for the physician. The teaching of the skills is nowadays made easier with the <