Fascioliasis due to Fasciola hepatica (Linnaeus, 1758) is an endemic disease on the Northern Bolivian Altipiano, where human prevalences and intensities arc the highest known, sheep and cattle are the main reservoir hosts, and pigs and donkeys the secondary ones. Investigations were carried out to study the viability of metacercariae experimentally obtained from eggs shed by naturally infected Altiplanic sheep, cattle, pigs and donkeys. A total of 157 Wistar rats were infected with doses of 5, 10, 20 and 150 metacercariae. Metacercariae aged for different number of weeks were used to analyse the influence of age on their viability. The number of worms successfully developed in each rat was established by dissection. Results obtained show that metacercarial infectivity is dependent upon storage time, being lower when metacercariae arc older. The maximum longevity is 31 weeks using doses of 20 metacercariae per rat and 48 weeks with 150 metacercariae per rat, although in the latter case only a very low percentage of worms is recovered. Age-related infectivity of metacercariae from Altiplanic F. hepatica does not significantly differ from that of the liver fluke in lowlands of other countries. Concerning the influence of the isolate according to host species, results indicate that metacercarial viabilities of pig and donkey isolates are similar to the viabilities of metacercariae of sheep and cattle isolates. Thus, pig and donkey have a high transmission potential capacity concerning this aspect. This fact is of great importance for the control of human and animal fascioliasis in this highly endemic zone.
Prenatal development of cord blood monocytes and tissue macrophages was studied in pig foetuses by immunophenotyping and functional assays. The function of peripheral blood monocytes was compared in germ- free and conventional piglets. First macrophages were identified by electron microscopy in foetal liver on the 25th day of gestation. Monoclonal antibodies against porcine CD45 and SWC3 antigens were used for flow cytometric identification of myelomonocytic cells in cell suspensions prepared from the yolk sac, foetal liver, spleen and cord blood. Leukocytes expressing the common myelomonocytic antigen SWC3 were found in all organs studied since the earliest stages of development. Opsonized zymosan ingestion assay was used to determine the phagocytic capacity of foetal mononuclear phagocytes isolated from cord blood, liver and spleen. In the foetal liver, avid phagocytosis of apoptic cells had been found to occur before cells were able to ingest zymosan in vitro. The first cells capable of ingesting zymosan particles were found on the 40th day of gestation in umbilical blood and 17 days later in foetal spleen and liver. Their relative proportion increased with age. Cord blood monocytes and peripheral blood monocytes in germ-free piglets had low oxidatory burst activity as shown by iodonitrophenyl tetrazolium reduction assay. A remarkable increase of oxidatory burst activity was observed in conventional piglets, probably due to activation of immune mechanisms by the microflora colonizing gastrointestinal tract.
The purpose of this study was to elucidate the intestinal serotonin (5-HT) receptor subtypes involved in fluid transport in the pig jejunum in uioo. The fluid accumulating effect of intraluminally administered 5-HT, renzapride, methysergide, ketanserin, granisetron, citalopram and intravenous indomethacin, was tested in tied- off loops in uiuo. 5-HT caused a dose-dependent fluid accumulation, which was reduced by indomethacin by about 30 %. Renzapride, methysergide, ketanserin, granisetron and citalopram all caused fluid accumulation. Taking into account these fluid accumulating effects, renzapride, methysergide, ketanserin and granisetron reduced the fluid accumulating effect of 5-HT, giving a maximal reduction of 70, 46, 76, and 80 %, respectively. These data suggest the existence of intestinal 5-HT receptor subtypes involved in fluid transport in the pig jejunum. The antagonistic effects of indomethacin, ketanserin and granisetron, suggest the involvement of prostangladins, as well as the 5-HT2 and the 5-HT3 receptor subtypes in the fluid accumulating response of 5-HT.
The involvement of the mTOR system/enzyme sirtuin 1 (SIRT1) intracellular signaling system in the control of ovarian functions and its role in mediating hormonal action on the ovary has been proposed, but this hypothesis should be supported by a demonstrated influence of hormones on mTOR/SIRT1. Therefore, the aim of our in vitro experiments was to examine the effect of the known hormonal regulators of ovarian functions, such as follicle-stimulating hormone (FSH), oxytocin (OT) and insulin-like growth factor I (IGF-I), on mTOR/SIRT1. The accumulation of SIRT1 in porcine ovarian granulosa cells cultured with and without these hormones (at doses of 1, 10 or 100 ng.ml-1 ) was evaluated using immunocytochemistry. It was observed that the addition of FSH (at 10 ng.ml-1 but not at 1 or 100 ng/ml) and OT (at all tested doses) increased the expression of SIRT1 in ovarian cells. In addition, 100 ng.ml-1 , but not at 1 or 10 ng.ml-1 , of IGF-I decreased SIRT1 accumulation. Our observations are the first demonstration that hormones can directly regulate the ovarian mTOR/SIRT1 system and that this system could mediate the action of hormonal regulators on the ovary.