RESUMO
OBJECTIVE: The incidence of the acquired immunodeficiency syndrome (AIDS) has increased in Santa Catarina State in Brazil over the last years, with a high number of infected women and children. The purpose of this study was to establish the main characteristics of the children from this State whose HIV serologic tests were positive. METHODS: This was a descriptive study of 176 children with positive serologic tests to HIV, conducted in the Hospital Infantil Joana de Gusmão, Florianópolis City, Santa Catarina State, Brazil. RESULTS: Most of the children (105 cases, 59.6%) were born in Florianópolis, Capital of Santa Catarina State, and Itajaí (22 cases, 12.5%). Vertical transmission of HIV was observed in 167 patients (94.9%). Among 167 HIV-positive mothers, 77 (46.1%) of them acquired the virus by sexual transmission and 35 (21.0%) by use of injectable drugs. However, among 89 HIV-positive fathers, 63 (70.7%) of them used to take drugs. The average age of the HIV-positive children whose serologic tests became negative was 10.5 months. Among 103 symptomatic patients, 87 (84.5%) presented hepatomegaly, 81 (78.6%) lymphadenopathy, 66 (64.0%) splenomegaly, 59 (57.3%) skin bruises, 54 (52.4%) recurrent bronchopneumonia and 50 cases (48.5%) recurrent diarrhea. The most frequent opportunistic infection was mucocutaneous candidiasis that occurred in 41 children (39.8%). CONCLUSIONS: The characteristics were similar to those reported in the literature. A great concentration of HIV infected persons was observed in the coast area where there are three harbor towns, an elevated number of injectable drug users and presence of many tourists.
Assuntos
Síndrome do Nó Sinusal , Animais , Atropina/farmacologia , Eletrocardiografia , Cardiopatias/complicações , Testes de Função Cardíaca , Frequência Cardíaca/efeitos dos fármacos , Humanos , Isoproterenol/farmacologia , Propranolol/farmacologia , Coelhos , Síndrome do Nó Sinusal/diagnóstico , Síndrome do Nó Sinusal/patologia , Síndrome do Nó Sinusal/fisiopatologia , Nó Sinoatrial/patologia , Nó Sinoatrial/fisiopatologiaRESUMO
Mathematical modeling of propagation in the squid giant axon using the Hodgkin-Huxley partial differential equation for propagation in a cable-like cell allowed us to study the effect of reduction in maximal sodium conductance in a short segment of the "axon membrane". The phase plane (V,V) display of the action potentials calculated in segments ahead of the gNa+ depressed site exhibited peculiar inflections in their ascending portion which are absent in the control situation. These inflections (upward or downward) varied with the distance from the depressed segments. The voltage of the first inflection point of the phase trajectories was an exponential function of this distance. This voltage is in close agreement with threshold voltage at points within a distance of 1.4 mm from the depressed segments. The model reproduces, qualitatively, the experimental behaviour of the squid axon topically exposed to TTX.
Assuntos
Axônios/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Sódio/metabolismo , Tetrodotoxina/farmacologia , Animais , Decapodiformes , Canais Iônicos , Modelos BiológicosRESUMO
Inotropic effects on strips of left atria promoted by 1-epinephrine, increase in frequency, post-extrasystolic potentiation, and by increase in extracellular calcium concentration were studied at 28 C and 36 C. The results show that at lower temperature the resulting changes in temporal parameters (activation time, deactivation time and duration above 10% of maximum force) are greater than those at the higher temperature. AT 36 C inotropic interventions have more prominent effects on the tension development and its first derivative, while changes in temporal parameters become less conspicuous. It is concluded that the inotropic interventions regulate the strength of contraction more effectively at 36 C and the temporal aspects of contraction more effectively at 28 C.
Assuntos
Contração Miocárdica , Temperatura , Animais , Função Atrial , Cálcio/farmacologia , Epinefrina/farmacologia , Frequência Cardíaca , Contração Miocárdica/efeitos dos fármacos , CoelhosRESUMO
A phase-plane diagram, obtained by plotting force versus the rate of force during isometric contractions, was used for determination of the mechanical properties of rabbit left atria. Considering the muscle as a two component mechanical analog we found: (a) the initial slope of the phase-plane diagram (m1) is proportional to the product KVmax, where K is the stiffness of the series elastic component, and (b) the final slope of the phase-plane diagram (m3) is equal to the product -Kb, where b is a constant with dimensions of velocity, and may be related to the absolute rate of energy liberation. It is shown that m1 increases with positive inotropic interventions (frequency increase, epinephrine, post-extrasystolic potentiation, elevation of calcium and increase in temperature) but does not change as a function of muscle length. The final slope M3 increases with frequency, temperature and epinephrine; decreases with calcium and stretch, and does not change with post-extrasystolic potentiation. The results also suggest that the change in m3 depends on the particular inotropic intervention. This supports the idea that separate mechanisms are responsible for the process of contraction and relaxation.
Assuntos
Contração Miocárdica , Temperatura , Animais , Cálcio/farmacologia , Cloretos/farmacologia , Epinefrina/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , CoelhosRESUMO
Inotropic effects on strips of left atria promoted by 1-epinephrine, increase in frequency, post-extrasystolic potentiation, and by increase in extracellular calcium concentration were studied at 28 C and 36 C. The results show that at lower temperature the resulting changes in temporal parameters (activation time, deactivation time and duration above 10
of maximum force) are greater than those at the higher temperature. AT 36 C inotropic interventions have more prominent effects on the tension development and its first derivative, while changes in temporal parameters become less conspicuous. It is concluded that the inotropic interventions regulate the strength of contraction more effectively at 36 C and the temporal aspects of contraction more effectively at 28 C.
RESUMO
A phase-plane diagram, obtained by plotting force versus the rate of force during isometric contractions, was used for determination of the mechanical properties of rabbit left atria. Considering the muscle as a two component mechanical analog we found: (a) the initial slope of the phase-plane diagram (m1) is proportional to the product KVmax, where K is the stiffness of the series elastic component, and (b) the final slope of the phase-plane diagram (m3) is equal to the product -Kb, where b is a constant with dimensions of velocity, and may be related to the absolute rate of energy liberation. It is shown that m1 increases with positive inotropic interventions (frequency increase, epinephrine, post-extrasystolic potentiation, elevation of calcium and increase in temperature) but does not change as a function of muscle length. The final slope M3 increases with frequency, temperature and epinephrine; decreases with calcium and stretch, and does not change with post-extrasystolic potentiation. The results also suggest that the change in m3 depends on the particular inotropic intervention. This supports the idea that separate mechanisms are responsible for the process of contraction and relaxation.
RESUMO
A phase-plane diagram, obtained by plotting force versus the rate of force during isometric contractions, was used for determination of the mechanical properties of rabbit left atria. Considering the muscle as a two component mechanical analog we found: (a) the initial slope of the phase-plane diagram (m1) is proportional to the product KVmax, where K is the stiffness of the series elastic component, and (b) the final slope of the phase-plane diagram (m3) is equal to the product -Kb, where b is a constant with dimensions of velocity, and may be related to the absolute rate of energy liberation. It is shown that m1 increases with positive inotropic interventions (frequency increase, epinephrine, post-extrasystolic potentiation, elevation of calcium and increase in temperature) but does not change as a function of muscle length. The final slope M3 increases with frequency, temperature and epinephrine; decreases with calcium and stretch, and does not change with post-extrasystolic potentiation. The results also suggest that the change in m3 depends on the particular inotropic intervention. This supports the idea that separate mechanisms are responsible for the process of contraction and relaxation.
RESUMO
Inotropic effects on strips of left atria promoted by 1-epinephrine, increase in frequency, post-extrasystolic potentiation, and by increase in extracellular calcium concentration were studied at 28 C and 36 C. The results show that at lower temperature the resulting changes in temporal parameters (activation time, deactivation time and duration above 10
of maximum force) are greater than those at the higher temperature. AT 36 C inotropic interventions have more prominent effects on the tension development and its first derivative, while changes in temporal parameters become less conspicuous. It is concluded that the inotropic interventions regulate the strength of contraction more effectively at 36 C and the temporal aspects of contraction more effectively at 28 C.