RESUMO
During an outbreak of yellow fever (rural form of the infection) occurred recently in the State of Goiás, Brazil, a patient, with clinical manifestations suggestive of the infection, died in the University Hospital of Brasilia, DF, on the fifth day from admission. Postmortem examination revealed, microscopically, the characteristic alterations of the infection, and discovered in the lungs and hilar lymph nodes round microrganisms identified as adiaconidia of Emmonsia parva var. crescens.
Assuntos
Chrysosporium , Pneumopatias Fúngicas/complicações , Febre Amarela/complicações , Evolução Fatal , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
During an outbreak of yellow fever (rural form of the infection) occurred recently in the State of Goiás, Brazil, a patient, with clinical manifestations suggestive of the infection, died in the University Hospital of Brasilia, DF, on the fifth day from admission. Postmortem examination revealed, microscopically, the characteristic alterations of the infection, and discovered in the lungs and hilar lymph nodes round microrganisms identified as adiaconidia of Emmonsia parva var. crescens.
Durante um surto de febre amarela (forma rural da infecção) instalado, em fins de 1999, no Estado de Goiás, Brasil, um enfermo, com sintomatologia suspeita, faleceu no Hospital Universitário de Brasília, DF, cinco dias após a admissão. À necropsia, microscopicamente, além das alterações hepáticas características da infecção, encontraram-se nos pulmões e linfonodos hilares, estruturas arredondadas, reconhecidas como adiaconídios de Emmonsia parva var. crescens.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Chrysosporium , Febre Amarela/complicações , Pneumopatias Fúngicas/complicações , Evolução FatalRESUMO
We studied the effect of oral cholecalciferol treatment on the endothelium-dependent vascular relaxation and hyperpolarization induced by acetylcholine (ACh), which is impaired in spontaneously hypertensive rats (SHR). Adult female SHR and normotensive Wistar-Kyoto rat (WKY) controls received 125 microg of cholecalciferol per kilogram body weight per day for 6 weeks. The responses to ACh of the isolated mesenteric vascular bed and mesenteric artery rings were measured, as well as the smooth muscle cell membrane potential. After cholecalciferol treatment, the systolic blood pressure and basal perfusion pressure of the mesenteric vascular bed of the SHR fell to control levels. The relaxant and hyperpolarizing effects of ACh, which are reduced in SHR, were also brought to control levels after cholecalciferol treatment. These effects of ACh were inhibited by N(omega)-nitro-L-arginine in SHR and by apamin in WKY. After cholecalciferol treatment, SHR hyperpolarizing responses showed the same inhibition pattern as those of WKY. This indicates that, after cholecalciferol treatment, SHR vascular mesenteric preparation responses to ACh are mediated by endothelium-derived hyperpolarizing factor, which induces activation of Ca(2+)-dependent K(+) channels, as in WKY. In untreated SHR, the ACh-mediated response is entirely due to ACh acting via the release of nitric oxide.
Assuntos
Colecalciferol/farmacologia , Hipertensão/fisiopatologia , Vasodilatação/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Colecalciferol/uso terapêutico , Interações Medicamentosas , Feminino , Hipertensão/tratamento farmacológico , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Vasodilatadores/farmacologiaRESUMO
1. The mechanism responsible for blood pressure reduction in spontaneously hypertensive rats (SHR) after prolonged cholecalciferol treatment was studied. Two-week treatment of SHR with 0.125 mg cholecalciferol kg-1 body weight per day orally caused significant reductions of systolic blood pressure and of the resting perfusion pressure of the mesenteric vascular bed at constant flow. 2. In addition, the treated animals presented a normalization of the maximum vasoconstriction response to noradrenaline and a reduction of the maximum effect of the adrenaline concentration-response curves. This latter effect probably was due to recovery of the impaired Ca(2+)-dependent K+ channels coupled to alpha 2-adrenoceptors since it was prevented by apamin. 3. The treatment with cholecalciferol also normalized the smooth muscle cell membrane potential of de-endothelialized mesenteric arteries of SHR and their hyperpolarizing responses to alpha 2-adrenergic agonists, which were depressed in untreated SHR. 4. In mesenteric rings with endothelium, alpha 2-adrenergic agonists caused similar hyperpolarizing responses in the SHR and in normotensive Wistar (NWR) and Wistar Kyoto (WKY). In non cholecalciferol-treated SHR the hyperpolarizing mediator involved in this effect was NO, while in NWR it was the endothelium-derived hyperpolarizing factor (EDHF). After cholecalciferol treatment, the hyperpolarization induced by alpha 2-adrenergic agonists in SHR smooth muscle cells was mediated by EDHF, as in NWR. 5. Our results indicate that the hypotensive effect of cholecalciferol in the SHR is probably due to the normalization of vascular reactivity, by restoring the functioning of apamin- and ATP-sensitive K+ channels located in the vascular smooth muscle cell membrane, which are impaired in the SHR.
Assuntos
Anti-Hipertensivos/farmacologia , Colecalciferol/farmacologia , Hipertensão/tratamento farmacológico , Artérias Mesentéricas/metabolismo , Canais de Potássio/fisiologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Endotélio Vascular/fisiologia , Feminino , Hipertensão/fisiopatologia , Potenciais da Membrana/efeitos dos fármacos , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/fisiopatologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Ratos WistarRESUMO
1. The diet of spontaneously hypertensive rats (SHR) and normotensive Wistar rats (NWR) was supplemented with 12.5 micrograms cholecalciferol per 100 g body weight daily, by gavage, for 4 weeks. 2. The amplitude of the contractile responses of aortic rings from SHR to potassium and adrenaline, which was smaller than in NWR aortae, was increased after treatment with cholecalciferol. No further changes were observed in the responses of NWR and SHR aortae in the presence of 100 nM apamin. 3. The membrane potentials of aortae from SHR, which were higher than those of aortae from NWR, decreased after treatment with cholecalciferol. Further depolarization was observed in aortic rings from NWR, but not in aortic rings from SHR, after their preincubation with 100 nM apamin. 4. It is concluded that cholecalciferol normalizes the membrane potential and contractility of aortae from SHR, probably through an effect on lipid composition and structure of the plasma membrane.
Assuntos
Aorta Torácica/fisiologia , Colecalciferol/farmacologia , Hipertensão/fisiopatologia , Músculo Liso Vascular/fisiologia , Animais , Aorta Torácica/efeitos dos fármacos , Apamina/farmacologia , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Dieta , Eletrofisiologia , Epinefrina/metabolismo , Hipertensão/genética , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Cloreto de Potássio/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos WistarRESUMO
The effect of clonidine on the mesenteric vascular bed and the isolated mesenteric artery was examined in preparations in which tonus was induced by norepinephrine or endothelin. In preparations precontracted by norepinephrine, clonidine caused a relaxation which was not inhibited by the alpha-2 antagonists yohimbine and idazoxan or by the K+ channel blockers apamine, tetraethylammonium and glibenclamide. In preparations precontracted with endothelin, clonidine increased the depolarization and induced a contraction. Both these effects were inhibited by prazosin. In isolated mesenteric arteries, norepinephrine cause a significant depolarization that was inhibited by clonidine or prazosin. On the other hand, clonidine caused a hyperpolarization which was inhibited by idazoxan or yohimbine, but not by prazosin. This hyperpolarization was also abolished by apamine, tetraethylammonium and glibenclamide. It is concluded that clonidine acts on alpha-1 adrenoceptors as a partial agonist, causing relaxation of the mesenteric artery precontracted with norepinephrine or contraction of preparations precontracted with endothelin. Moreover, clonidine can open K+ channels and hyperpolarize the plasma membrane of mesenteric artery by acting on alpha-2 adrenoceptors.
Assuntos
Antagonistas de Receptores Adrenérgicos alfa 1 , Agonistas de Receptores Adrenérgicos alfa 2 , Agonistas alfa-Adrenérgicos/farmacologia , Antagonistas Adrenérgicos alfa/farmacologia , Clonidina/farmacologia , Artérias Mesentéricas/efeitos dos fármacos , Animais , Feminino , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Artérias Mesentéricas/fisiologia , Ratos , Ratos WistarRESUMO
1. The diet of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) and Wistar (NWR) rats was supplemented with either 2% calcium lactate in the drinking water or 12.5 micrograms vitamin D3 100 g-1 body weight daily by gavage, for 14 days. 2. The blood pressure of the SHR treated with either calcium or vitamin D decreased to the same levels as that of WKY and NWR. 3. The response to bradykinin of the SHR isolated duodenum, which is predominantly contractile, upon treatment with vitamin D (but not with calcium), became predominantly relaxant, approaching the normal behavior of the WKY and NWR duodenum. 4. The relaxant responses of the SHR and WKY duodenum to potassium were smaller than those of NWR, but treatment with vitamin D increased the response in all three rat strains. 5. It is concluded that, besides sharing the hypotensive effect of calcium, vitamin D treatment of SHR has an effect on the duodenum smooth muscle which might be due to calmodulin-dependent activation of calcium-dependent potassium channels.