Effect of antihypertensive agents on stellate cells during liver regeneration in rats

BACKGROUND: Although most studies have focused on the hepatocytes, all the hepatic cells participate in the regenerative process, among them the stellate cells. The stellate cells are mesenchymal cells involved in local neurotransmission and paracrine regulation of several liver functions. Acute hepatic tissue loss promotes the proliferation and activation of stellate cells from a quiescent state to myofibroblast-like cells. AIM: Investigate the effects of antihypertensive agents on the stellate cell population during the liver regenerative phenomenon in rats. METHODS: Adult male Wistar rats received lisinopril, losartan, bradykinin, or saline solution in a proportional volume, intraperitoneally, before and after 70 percent partial hepatectomy. Animals from the experimental and saline groups were sacrificed at 36 hours after partial hepatectomy. The alpha-smooth muscle actin labelled stellate cells population was counted in the periportal and pericentral zones of the liver specimen. RESULTS: The labelled stellate cells were more numerous in the control group both in the periportal and pericentral zones at 36 hours after partial hepatectomy than at the other times. The population of stellate cells was significantly lower in the losartan group and higher in the bradykinin and lisinopril groups than in the control group. CONCLUSIONS: These results suggest that losartan can inhibit and bradykinin and lisinopril can stimulate the stellate cell population during liver regeneration in rats. These cells synthesize several substances to stimulate liver regeneration.

Efeito de agentes anti-hipertensivos sobre as células estreladas durante a regeneraçäo hepática em ratos / Effect of antihypertensive agents on the starry cells during hepatic regeneration in rats

O efeito de um inibidor da enzima conversora da angiotensina (lisinopril), de um antagonista do receptor da angiotensina II (losartan) e da bradicinina na população de células estreladas (CE) durante o fenômeno regenerativo hepático foi estudado. Ratos machos Wistar receberam lisinopril, losartan, bradicinina ou solução salina em volumes proporcionais, intraperitonealmente, antes e após hepatectomia parcial a 70 por cento (HP). Cinco animais de cada grupo experimental e controle foram sacrificados sob anestesia com éter em 36 horas após a HP. A população de CE marcadas para alfa-actina de músculo liso foi estimada nas zonas periportal e pericentral das amostras hepáticas. A população de CE foi menor no grupo tratado com losartan, e maior nos grupos tratados com bradicinina e lisinopril que no grupo controle. Estes resultados sugerem que o losartan pode inibir, e a bradicinina e o lisinopril podem estimular a população de CE durante a regeneração hepática em ratos.

Cerebral ventricle sites involved in the central hypertensive response to acetylcholine in unanesthetized rats

It is well known that the injection of acetylcholine (ACh) into the lateral ventricles of the brain (ICV) causes blood pressure increases in unanesthetized rats. However, the actual brain nuclei involved in the mediation of the pressor response to ACh are yet unknown. We report doserelated pressor responses when ACh was injected into the III ventricle or the cerebral aqueduct of similar magnitude to those observed after ICV injection of ACh. No blood pressure effects were observed after the injection of ACh into the IV ventricle. Obstructions of selected ventricular spaces with plugs of Nivea cream were performed to identify the ventricular area involved in the pressor response to ICV-injected ACh. Obstructions of the III ventricle or the aqueduct were similarly effective in significantly reducing the pressor response to ACh injected into the lateral ventricle. Obstructions of the IV ventricle did not affect the pressor response to ICV-injected ACh. The results with the injection of ACh into different ventricular spaces and the occlusion of delimited portions of the ventricular spaces suggest: 1) That prosencephalic, diencephalic as well as rhombencephalic nuclei play a minor role in the mediation of the pressor response to ICV-injected ACh, and 2) that the major site involved in the pressor response to ACh is located in a brain area close to the cerebral aqueduct.

Epidemiology of Chagas' heart disease

Chagas' disease is a major public health problem in Latin America. About 16 million persons are affected and 90 million others are exposed to the risk of being infected by the parasite. The knowledge of epidemiological aspects of the disease allowed to delineate the strategies for the control of the disease related with the vectorial transmission. However, these strategies have had no priority in all endemic countries. Rural-urban migration in most endemic areas carried infected individuals to urban centers increasing the problem of Chagas' disease by blood transfusion. In Brazil the control program has reached good results in the last years and in several states the vectorial transmission was controlled. More recently, hemotherapic practices are performed using screening procedures but this practice must be improved in order to eliminate the possibility of Chagas' disease transmission by another ways (congenital, accidental, oral, etc.). An adequate health care to the infected persons must be improved in order to diminish the social costs of the severe cardiopathy which has been responsible for the adults premature deaths.

Parasitismo natural de bufalinos em Botucatu, SP, Brasil: III. Dinâmica do parasitismo gastro-intestinal em vacas e suas crias / Natural parasitsm of buffalo cows in Botucatu, SP, Brazil: III. Dynamics of gastro-intestinal parasitism in cows and calves

Natural parasitism of buffalo cows in Botucatu, SP, Brazil - III. Dynamics of gastro-intestinal parasitism in cows and calves - Gastro-intestinal parasitism of 24 buffalo cows before parturition, and post-parturition, their infection and that of their respective calves during the following 30 weeks were studied. Willis, Hoffmann and whenever possible, the modified Gordon & Whitlock techniques were used for fecal examinations. Toxocara vitulorum eggs were the earliest forms encountered in calves feces, as follows: during the 1st week after birth, 58.33% of the calves were positive, and in the 4th week, 100% of these animals were positive. Eggs of Strongyloides sp were in the 1st week after birth in two of the calves and in the 5th week, all for them were positive. The next parasites to appear were the Coccidia of which oocysts were detected in the feces of two calves in the 2nd week after birth, and 58.33% of the calves were positive for these in the 3rd week, and in the 6th week, all calves shed oocysts in their feces. On the other hand, eggs of Strongylids were the last forms to appear in calves feces. However, despite their sporadic appearance in the feces, eggs of these parasites were observed continuously from the 11th week onwards, and at this point, the percentage of positive samples began to increase to reach its peak. Relatively to adult animals, eggs of T. vitulorum were observed in the feces of 11 cows, one or twice at most; eggs of Strongyloides sp were seen only once in the feces of four buffalo cows and eggs of Strongylids in 21 out of 24 cows. Oocysts of Coccidia were observed in 16 cows. Mechanisms of infestation of calves with these parasites are discussed

Chromosomes of Pomacea sp (Perry, 1811) (Mesogastropoda, Mollusca)

O estudo cariótípico em Pomacea sp é importante em virtude das grandes dificuldades taxonômicas apresentadas por este gênero e também por ser utilizado em experiências como controlador biológico da Biomphalaria glabrata, hospedeiro intermediário do Schistosoma mansoni. A técnica utilizada para a obtençäo de metáfase foi a de suspensäo celular, elabroada em nosso laboratório. O cariótipo foi obtido em preparaçöes realizadas com embriöes, no estágio de veliger jovem. Esta espécie possui o numero diplóide de 2n=28 cromossomos constituído de 9 pares metacêntricos, 4 pares submetacêntricos e 1 par subtelocêntrico. O braço curto do par subtelocêntrico se mostrou positivo ao AgNO3, local da constriçäo secundária (RON). A análise meiótica confirmou a presença de n=14 cromossomos

CNS catecholaminergic mechanisms in cardiovascular control

Existem evidências conclusivas da participaçäo de catecolaminas na mediaçäo central da pressäo arterial. A atuaçäo das catecolaminas estende-se a todos os segmentos do controle cardiovascular pelo SNC, envolvendo tanto a ativaçäo dos sistemas nervosos simpático e hipotalâmicos-neurohipofisário quanto modulaçäo da atividade vagal parassimpática. A seletividade dessa atuaçäo difusa é garantida pela multiplicidade de receptores envolvidos, possibilitando atuaçäo tanto inibitória quanto excitatória das catecolaminas em um mesmo neurônio. A ativaçäo desses receptores pode causar tanto elevaçäo da pressäo arterial como respostas hipotensoras, dependendo da espécie animal estudada, do sitio de administraçäo ou da utilizaçäo ou näo de anestésicos. Entretanto, existem evidências indicativas de que mecanismos alfa2-centrais estariam preferencialmente envolvidos na mediaçäo de respostas hipotensoras, enquanto mecanismos alfa1-atuariam mediando respostas hipertensoras. Por outro lado, o papel desempenhado por receptores ß-adrenérgicos centrais é ainda controvertido, envolvendo sua participaçäo tanto em respostas pressoras quanto depressoras

Parasitismo natural de bufalinos em Botucatu, S.P., Brasil. I. Observaçöes sobre Toxocara vitulorum Goeze, 1782 / Natural parasitism of the buffalo en Botucatu, S.P., Brazil. I. Observations on Toxocara vitulorum Goeze, 1782

Durante a gestaçäo e depois do parto, amostras de fezes de 24 vacas búfalas e de suas respectivas crias foram examinadas usando-se os métodos de WILLIS, HOFFMAN e, quando possível, GORDON & WHITLOCK. Em 45,83% das búfalas foram observados, por uma ou no máximo duas vezes, ovos do parasita nas fezes, em duas delas 30 dias antes do parto e em oito cerca de 30 dias após, o que leva a supor que mecanismos hormonais relacionados ao parto ou lactaçäo tenham açäo sobre a relaçäo parasita-hospedeiro. Dos bezerros 100% mostraram-se parasitados, 58,33% deles na primeira semana de vida, 87,50% na segunda, 95,83% na terceira e 100% deles na quarta. O encontro inicial de ovos nas fezes dos bezerros indica que a maioria deles infestou-se por via transplacentária, havendo apenas alguns que talvez tenham se infestado via leite. A partir da 18a. semana de vida näo foram detectados ovos nas fezes (no máximo até 118 dias), sendo que a duraçäo do período de positividade variou de três a 17 semanas. Näo foram constatadas diferenças entre bezerros machos e fêmeas quanto ao parasitismo por T. vitulorum, nem correlaçäo entre o número de vezes que as vacas gestaram e a infestaçäo dos bezerros delas nascidos

Cryptosporidiosis among patients with acquired immunodeficiency syndrome (AIDS) in the county of Säo Paulo, Brazil

Criptosporidiose em pacientes acometidos pela síndrome de imunodeficiência adquirida (AIDS), no município de Säo Paulo, Brasil. Amostras de fezes de 157 pacientes acometidos pela síndrome de imunodeficiência adquirida, residentes no município de Säo Paulo, foram submetidas a diversas técnicas para pesquisa de Cryptosporidium sp... Entre as diversas técnicas testadas para o preparo das lâminas (esfregaço direto, método de sedimentaçäo espontânea e concentraçäo pelo formol-éter) a concentraçäo pelo formol-éter foi a que forneceu melhores resultados, superando nitidamente as demais. Nas 157 amostras preparadas por esta técnica, após coloraçäo pelo método de Kinyoun ou pela fucsinacarbólica dimetilsulfóxido, encontraram-se 19 (12,1%) positivas para oocistos de Cryptosporidium sp.