RESUMO
One of the most common chronic diseases that causes missed school days and workdays is pediatric asthma, producing education, health and economic delays in low and middle-income countries. A patient-centered remarkable therapeutic strategy in the prevention and treatment of chronic diseases is the Therapeutic Patient Education (TPE) which denotes an outstanding difference in the outcomes, from the awareness, to the personal treatment adaption to prevent crises. In this paper, an intervention of TPE with learning objects (LOs) of a pediatric asthma course, designed to train the uncontrolled patient and the caregiver as a team on the specific knowledge to self-control the disease, was carried out at a health facility in Mexico. The Asthma Control Test (ACT) was used and the learning performance was evaluated with formative quizzes. A randomized controlled trial was designed, with pairs of children patients and caregivers during 60 days; the control group was trained with the usual approach, receiving general information about the disease. ACT measures showed statistical significance for the TPE group after the use of the LOs, achieving a controlled state, while the control group did not show difference. Also, the intervention group obtained a higher score in learning performance assessment. The users learned how to avoid risks, the personal triggers of the patient, how to correctly use the different treatments and accessories, consequently, they learned how to self-manage the disease. Our study also confirmed that control of asthma is not only a matter of knowledge, but financial issues to afford the treatment.
Assuntos
Asma/terapia , Educação de Pacientes como Assunto/organização & administração , Criança , Pré-Escolar , Feminino , Humanos , Masculino , México , Assistência Centrada no Paciente , Desenvolvimento de Programas , Avaliação de Programas e Projetos de SaúdeRESUMO
Cytoskeletal F-actin associated with synaptic vesicles and granules plays an important role during Ca(2+)-mediated exocytosis. In the present work, we have used amperometry and confocal fluorescence to study the role of internal Ca(2+) in the rearrangement of F-actin (visualised with phalloidin-Alexa 546) during exocytosis in rat mast cells. The F-actin-depolymerising drug, latrunculin A, and the ryanodine receptor agonists ryanodine and caffeine that, per se did not induce exocytosis, enhanced the exocytotic responses elicited by compound 48/80 (C48/80). They also induced cortical actin depolymerisation in the presence or absence of external Ca(2+). Degranulation induced by C48/80 was accompanied by the formation of a cytoplasmic F-actin network. Depletion of internal Ca(2+) with cyclopiazonic acid inhibited latrunculin potentiation of C48/80-stimulated exocytosis and completely blocked the formation of the cytoplasmic F-actin network. This indicates that the mobilisation of Ca(2+) from ryanodine-sensitive intracellular stores plays an important role in the depolymerisation of the cortical F-actin barrier and possibly in the formation of the internal F-actin network during exocytotic activation of peritoneal mast cells.
Assuntos
Citoesqueleto de Actina/fisiologia , Cálcio/metabolismo , Exocitose/fisiologia , Mastócitos/metabolismo , Polímeros/metabolismo , Rianodina/farmacologia , Citoesqueleto de Actina/metabolismo , Actinas/efeitos dos fármacos , Actinas/metabolismo , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Cafeína/farmacologia , Degranulação Celular , Citoplasma/metabolismo , Exocitose/efeitos dos fármacos , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Masculino , Mastócitos/efeitos dos fármacos , Mastócitos/fisiologia , Peritônio/citologia , Ratos , Ratos Sprague-Dawley , Tiazolidinas/farmacologia , p-Metoxi-N-metilfenetilamina/farmacologiaRESUMO
The regulation of the Ca2+ -induced Ca2+ release (CICR) from intracellular stores is a critical step in the cardiac cycle. The inherent positive feedback of CICR should make it a self-regenerating process. It is accepted that CICR must be governed by some negative control, but its nature is still debated. We explore here the importance of the Ca2+ released from sarcoplasmic reticulum (SR) on the mechanisms that may control CICR. Specifically, we compared the effect of replacing Ca2+ with Sr2+ on intracellular Ca2+ signaling in intact cardiac myocytes as well as on the function of single ryanodine receptor (RyR) Ca2+ release channels in panar bilayers. In cells, both CICR and Sr2+ -induced Sr2+ release (SISR) were observed. Action potential induced Ca2+ -transients and spontaneous Ca2+ waves were considerably faster than their Sr2+ -mediated counterparts. However, the kinetics of Ca2+ and Sr2+ sparks was similar. At the single RyR channel level, the affinities of Ca2+ and Sr2+ activation were different but the affinities of Ca2+ and Sr2+ inactivation were similar. Fast Ca2+ and Sr2+ stimuli activated RyR channels equally fast but adaptation (a spontaneous slow transition back to steady-state activity levels) was not observed in the Sr2+ case. Together, these results suggest that regulation of the RyR channel by cytosolic Ca2+ is not involved in turning off the Ca2+ spark. In contrast, cytosolic Ca2+ is important in the propagation global Ca2+ release events and in this regard single RyR channel sensitivity to cytosolic Ca2+ activation, not low-affinity cytosolic Ca2+ inactivation, is a key factor. This suggests that the kinetics of local and global RyR-mediated Ca2+ release signals are affected in a distinct way by different divalent cations in cardiac muscle cells.
Assuntos
Cálcio/metabolismo , Cátions Bivalentes/metabolismo , Miócitos Cardíacos/metabolismo , Estrôncio/metabolismo , Potenciais de Ação/fisiologia , Animais , Ratos , Retículo Sarcoplasmático/metabolismo , Fatores de TempoRESUMO
Mast cells exocytotically release histamine/serotonin in response to different secretagogues. We have used substance P and compound 48/80 to study the Ca++ dependency of serotonin exocytosis from peritoneal mast cells using carbon fiber amperometric techniques. The exocytotic release pattern consists of a burst of events superimposed on a slow, transient, amperometric current baseline increase. Cellular re lease parameters (number, frequency and total charge of amperometric events) and individual event characteristics (charge integral, half width and peak amplitude) were similar for the two secretagogues used. Zero Ca++ conditions greatly reduced, without completely abolishing,cellular release parameters. Cyclopiazonic acid, an inhibitor of the endoplasmatic Ca++ ATPase, reduced the cellular exocytotic capacity and diminished the amplitude of individual exocytotic events more effectively than the 0 Ca++ condition. The cyclopiazonic acid effects occurred in the presence of external Ca++, indicating that this condition is not sufficient for maintaining full exocytotic capacity. The results confirm the importance of intracellular Ca++ for exocytotic activation. For the first time evidence is presented that the integrity of intracellular Ca++ pools determines the amplitude and frequency of individual exocytotic events. Saponin, a non-specific detergent, also induced quantal release similar to that obtained with substance P and compound 48/80. This release was not dependent on extracellular Ca++, but cyclopiazonic acid significantly reduced individual exocytotic release.
Assuntos
Cálcio/fisiologia , Exocitose/fisiologia , Mastócitos/fisiologia , Animais , Células Cultivadas , Transporte de Íons/fisiologia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
The spatiotemporal distribution of intracellular Ca(2+) release in contracting skeletal and cardiac muscle cells was defined using a snapshot imaging technique. Calcium imaging was performed on intact skeletal and cardiac muscle cells during contractions induced by an action potential (AP). The sarcomere length of the skeletal and cardiac cells was approximately 2 micrometer. Imaging Rhod-2 fluorescence only during a very brief (7 ns) snapshot of excitation light minimized potential image-blurring artifacts due to movement and/or diffusion. In skeletal muscle cells, the AP triggered a large fast Ca(2+) transient that peaked in less than 3 ms. Distinct subsarcomeric Ca(2+) gradients were evident during the first 4 ms of the skeletal Ca(2+) transient. In cardiac muscle, the AP-triggered Ca(2+) transient was much slower and peaked in approximately 100 ms. In contrast to the skeletal case, there were no detectable subsarcomeric Ca(2+) gradients during the cardiac Ca(2+) transient. Theoretical simulations suggest that the subsarcomeric Ca(2+) gradients seen in skeletal muscle were detectable because of the high speed and synchrony of local Ca(2+) release. Slower asynchronous recruitment of local Ca(2+) release units may account for the absence of detectable subsarcomeric Ca(2+) gradients in cardiac muscle. The speed and synchrony of local Ca(2+) gradients are quite different in AP-activated contracting cardiac and skeletal muscle cells at normal resting sarcomere lengths.
Assuntos
Cálcio/metabolismo , Coração/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Contração Miocárdica/fisiologia , Potenciais de Ação , Animais , Anuros , Cálcio/análise , Estimulação Elétrica , Corantes Fluorescentes , Ventrículos do Coração , Compostos Heterocíclicos com 3 Anéis , Técnicas In Vitro , Cinética , Microscopia de Fluorescência , Modelos Teóricos , Fibras Musculares Esqueléticas/fisiologia , RatosRESUMO
Fluorescence signals from the calcium sensitive dyes Fluo-3 or Rhod-2 were obtained simultaneously with isometric tension in single fibres isolated from the anterior tibialis muscle of Leptodactylus insularis (20-22 degrees C). Fluo-3 fluorescence signals were transformed into [Ca2+]i transients as previously described. Most of the decay phase of single twitch transient is well fitted by a single exponential (tau of about 10 ms), followed by a slower declining component lasting tens of milliseconds. During short periods, 10 to 20 s, of low frequency stimulation, between 0.2 and 5 Hz, the basal [Ca2+]i increased slowly from 0.1 to about 0.4 microM, with only minor changes in the exponentially decaying phase. In fibres poisoned with thapsigargin or cyclopiazonic acid (1-2 microM) the tau of decay of fluorescence or Ca2+ transients of single twitches was very similar to that observed in non-poisoned fibres. Nevertheless, in poisoned fibres challenged with repetitive stimulation. the tau of Ca2+ transients decay increased from about 10 ms to >40 ms, while the basal [Ca2+]i increased from 0.1 to 2 microM. Short rest periods (about 5 min) could reverse these effects, indicating that they were not a direct consequence of SR Ca 2+ -ATPase inhibition. The correlation coefficient between tau of decay and basal [Ca2+]i was >0.8 (P<0.0001). Qualitatively similar results were obtained measuring Rhod-2 fluorescence signals. A lumped, two-compartment model could account for these results. Loading the fibres with EGTA-AM, diminished the effects of prolonged stimulation observed in poisoned fibres. Moreover, we show that the Na+ - Ca2+ exchange mechanism does not participate appreciably in fast Ca2+ removal.
Assuntos
Cálcio/metabolismo , Contração Isométrica/fisiologia , Músculo Esquelético/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Compostos de Anilina , Animais , Anuros , Sítios de Ligação/fisiologia , Soluções Tampão , ATPases Transportadoras de Cálcio/antagonistas & inibidores , ATPases Transportadoras de Cálcio/metabolismo , Estimulação Elétrica , Eletrofisiologia , Inibidores Enzimáticos/farmacologia , Corantes Fluorescentes , Cinética , Magnésio/metabolismo , Microscopia de Fluorescência , Modelos Biológicos , Fibras Musculares Esqueléticas/enzimologia , Músculo Esquelético/citologia , Parvalbuminas/fisiologia , Tempo de Reação/fisiologia , Sódio/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Tapsigargina/farmacologia , XantenosRESUMO
Cooling increases the twitch force of frog skeletal muscle (Rana temporaria; Rana pipiens), but decreases the twitch force of tropical toad muscle (Leptodactylus insularis). Action potentials and intramembranous charge movement in frog and toad fibers were slowed identically by cooling. Cooling increased the integral of twitch Ca2+ detected by aequorin in frog fibers (1.4-fold), while also decreasing the peak and slowing the rate of decay. Conversely, cooling decreased the integral (0.6-fold) and the peak of twitch Ca2+ in toad fibers, without affecting the rate of decay. The difference in entire Ca2+ transients may account for cold-induced twitch potentiation in frogs and twitch paralysis in toads. In sustained contractions of toad fibers, cooling markedly decreased maximum force caused by: (i) tetanic stimulation, (ii) two-microelectrode voltage clamp steps, (iii) high [K+], or (iv) caffeine. Maximum force in sustained contractions was decreased moderately by cooling frog fibers. Rapid rewarming and simultaneous removal of high [K+] or caffeine during a sustained contraction, caused toad muscle force to rise towards the value corresponding to the warm temperature. This did not occur after removing high [K+] or caffeine from toad fibers kept in the cold. Transmission electron micrographs showed no relevant structural differences. Parvalbumins are thought to promote relaxation of frog muscle in the cold. The unique parvalbumin isoforms in toad muscle apparently lack this property.
Assuntos
Anuros/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Ranidae/fisiologia , Animais , Cafeína/farmacologia , Cálcio/fisiologia , Temperatura Baixa , Estimulação Elétrica/métodos , Eletrofisiologia , Técnicas In Vitro , Membranas/fisiologia , Microscopia Eletrônica , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/ultraestrutura , Potássio/farmacologia , Rana pipiens/fisiologia , Rana temporaria/fisiologia , DescansoRESUMO
The effect of sulhydryl reagents on nonlinear membrane currents of frog skeletal muscle fibers has been studied using the triple Vaseline gap voltage-clamp technique. These compounds, which are known to interfere with depolarization contraction coupling, also appear to diminish intramembranous charge movement recorded with fibers polarized to -100 mV (charge 1). This effect, however, is accompanied by changes in the fiber membrane conductance and in most cases by the appearance of an inwardly directed current in the potential range between -60 and +20 mV. This current is reduced by both cadmium and nifedipine and does not occur in Ca-free solution, suggesting that it is carried by calcium ions flowing through regular calcium channels that are more easily activated in the presence of SH reagent. These changes in the membrane electrical active and passive properties decrease the quality and reliability of the P/n pulse subtracting procedure normally used for charge movement measurements. These effects can be substantially reduced by cadmium ions (0.1 mM), which has no effect on charge movement. When SH reagents are applied in the presence of cadmium, no effects are observed, indicating that this cation may protect the membrane from the reagent effects. The effects of -SH reagents can be observed by applying them in the absence of cadmium, followed by addition of the cation. Under these conditions the conductance changes are reversed and the effects of the SH reagents on charge movement can be measured with a higher degree of confidence. Maximum charge is reduced by 32% in the presence of 1.5 mM PCMB and by 31% in the presence of 2 mM PHMPS. These effects do not occur in the presence of DTT and in some cases they may be reversed by this agent. Charge 2, recorded in depolarized muscle fibers, is also reduced by these agents.
Assuntos
Canais Iônicos/efeitos dos fármacos , Músculos/fisiologia , Reagentes de Sulfidrila/farmacologia , Animais , Anuros , Cádmio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Ditiotreitol/farmacologia , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Músculos/citologia , Músculos/efeitos dos fármacos , Fibras Nervosas/efeitos dos fármacos , Nifedipino/farmacologia , Compostos Organomercúricos/farmacologia , Rana pipiensRESUMO
We have studied the effects of the sulfhydryl reagents on contractile responses, using either electrically stimulated single muscle fibers or short muscle fibers that were voltage-clamped with a two-microelectrode voltage-clamp technique that allows the fiber tension in response to membrane depolarization to be recorded. The sulfhydryl inhibitors para-chloromercuribenzoic acid (PCMB) and parahydroximercuriphenyl sulfonic acid (PHMPS), at concentrations from 0.5 to 2 mM, cause loss of the contractile ability; however, before this effect is completed, they change the fiber contractile behavior in a complex way. After relatively short exposure to the compounds, < 20 min, before the fibers lose their contractile capacity, secondary tension responses may appear after electrically elicited twitches or tetani. After losing their ability to contract in response to electrical stimulation, the fibers maintain their capacity to develop caffeine contractures, even after prolonged periods (120 min) of exposure to PHMPS. In fibers under voltage-clamp conditions, contractility is also lost; however, before this happens, long-lasting (i.e., minutes) episodes of spontaneous contractile activity may occur with the membrane polarized at -100 mV. After more prolonged exposure (> 30 min), the responses to membrane depolarization are reduced and eventually disappear. The agent DTT at a concentration of 2 mM appears to protect the fibers from the effects of PCMB and PHMPS. Furthermore, after loss of the contractile responses by the action of PCMB or PHMPS, addition of 2 mM DTT causes recovery of tension development capacity.