No abstract

The capacity of polymorphonuclear neutrophils (PMN) and other leucocytes of the innate immune system to expel their DNA in a controlled process into the extracellular environment to trap and kill pathogenic microorganisms led to a paradigm shift in our comprehension of host leucocyte-pathogen interactions. Formation of neutrophil extracellular traps (NETs) has recently been recognized as a novel effector mechanism of the host innate immune response against microbial infections. Meanwhile evidence has arisen that NET formation is a widely spread mechanism in vertebrates and invertebrates and extends not only to the entrapment of microbes, fungi and viruses but also to the capture of protozoan and metazoan parasites. PMN produce NETs after stimulation with mitogens, cytokines or pathogens in a controlled process which depends on reactive oxygen species (ROS) and the induction of the Raf-MEK-ERK-mediated signalling pathway cascade. NETs consist of nuclear DNA as a backbone decorated with histones, antimicrobial peptides, and PMN-specific granular enzymes thereby providing an extracellular matrix capable of entrapping and killing invasive pathogens. This review is intended to summarize parasite-related data on NETs. Special attention will be given to NET-associated mechanisms by which parasites, in particular apicomplexa, might be hampered in their ability to reproduce within the host cell and complete the life cycle.

A survey of Eimeria infections was performed in dairy goats and kids (<6 months old) of six farms from a dry desert area of Gran Canaria Island (Spain). The number of oocysts per gram of faeces (OPG) was determined by a modified McMaster technique over a total of 2,616 individual faecal samples taken from the rectum in monthly intervals. Eimeria oocysts were found in 96.1% of the samples with OPG ranging from 1 x 10(2) to 1.4 x 10(6). Kid goats had significantly (P < 0.001) higher OPG counts (46,496 +/- 5,228) than dairy females (2,225 +/- 287). Eight Eimeria species were identified, with Eimeria ninakohlyakimovae (30.0%), Eimeria arloingi (28.6%) and Eimeria alijevi (20.5%) being the most frequent species followed by Eimeria caprina (9.1%), Eimeria christenseni (4.5%), Eimeria jolchijevi (3.4%), Eimeria caprovina (3.2%) and Eimeria hirci (0.7%). Although significant differences were observed among goat groups and herds, the eight species were present in the six farms in both dairy goats and kids. The intensity of oocysts shedding was related to some factors such as the size of the herd and was further influenced by the prevailing climatic conditions of the area. The highest OPG counts were recorded during the hot season in dairy goats and close to weaning time in kids reared in small farms having no prophylactic treatments against eimeriosis.

No abstract

Administration of 4 mg of the antiprogestagen RU486 to 4-day-cyclic rats over 8 consecutive days starting on the day of estrus (Day 1) induced and anovulatory cystic ovarian condition with endocrine and morphological features similar to those exhibited in polycystic ovarian disease (PCO). To determine whether the RU486-treated rat responds in an analogous fashion to therapies similar to those that have been used to treat human PCO, RU486-treated rats were injection on Days 5 and 7 with 1) 1 mg of an LHRH antagonist (LHRHa), 2) 5 IU of human FSH (hFSH), 3) 2 mg of the antiandrogen flutamide (FLU), 4) 1 mg of the antiestrogen tamoxifen (TMX), or 5) 1 mg of the dopamine agonist bromocriptine (BRC). Controls were intact cyclic rats decapitated on estrus and rats injected with RU486 and the corresponding vehicles (saline or 70% ethanol) used with LHRHa, hFSH, FLU, TMX, and BRC injections. RU486-treated rats were decapitated on Day 9, and the serum concentrations of LH, FSH, prolactin (PRL), testosterone (T), and estradiol-17 beta (E2) were determined. Pituitary and ovary weight, number of follicular cysts, size of the corpora lutea, and rates of follicular growth and atresia were also noted. Finally, the ovulatory response to ovine LH (oLH) in rats treated with RU486 and injected with various doses of hFSH (5, 10, or 20 IU) was evaluated. While administration of LHRHa and of TMX decreased the serum concentrations of LH, T and E2 and the LH/FSH and T/E2, ratios, and injections of BRC and of FLU increased the serum concentration of LH and T, the administration of hFSH (10 IU) to RU486-treated rats increased only the serum levels of E2. All treatments decreased, though in different degrees, both the number of cysts and the rate of follicular atresia, and stimulated follicular growth. The positive effects on follicular growth and atresia were significantly higher in those rats injected with hFSH. Moreover, RU486-treated rats injected with different doses of hFSH ovulated in a dose-dependent manner in response to oLH. Rates deprived of the actions of progesterone through the administration of the antiprogestagen RU486 had 1) endocrine and morphologic alterations comparable to those observed in women with PCO, 2) analogous responses to therapies similar to those that have been used to treat human PCO, and 3) an ovulatory response to combined treatment with FSH and LH. These results establish the fundamental adequacy of using the RU486-treated rat as a PCO model.