Complement-dependent induction of DNA synthesis and cell proliferation in human liver connective tissue cells in vitro

Summary Liver connective tissue cells (LCTC) isolated from patients with fibrotic livers have morphological and biochemical characteristics of myofibroblasts. We have examined the proliferation of LCTC derived from normal livers and from livers with fibrosis of different etiologies, as well as proliferation of skin fibroblasts. We have compared proliferation rates in the presence of fresh human serum and heat-inactivated serum. While skin fibroblast and LCTC from normal liver showed no difference, proliferation of LCTC from fibrotic livers was markedly decreased in the presence of heat-inactivated serum. We demonstrate that the native complement component C1 is a factor involved in the induction of DNA synthesis and proliferation of LCTC isolated from fibrotic livers. We propose that native C1, acting probably in cooperation with other growth factors, is involved in the expansion of connective tissue cells during the development of liver fibrosis.     

Inspection and evaluation of host plant by the butterfly Mechanitis lysimnia (Nymph., Ithomiinae) before laying eggs: a mechanism to reduce intraspecific competition

Parasites of all kinds affect the behaviour of their hosts, often making them more susceptible to predators. The associated loss in expected future reproductive success of infected hosts will vary among individuals, with younger ones having more lose than older ones. For this reason, young hosts would benefit more by opposing the effects of parasites than old ones. In a laboratory study, the effects of the trematode Telogaster opisthorchis on the anti-predator responses of the upland bully (Gobiomorphus breviceps) and of the common river galaxias (Galaxias vulgaris) were examined in relation to fish age. In a bully population where parasites were very abundant, the magnitude of the fish's anti-predator responses decreased as the number of parasites per fish increased, and this effect was significantly more pronounced in age 2 + and, to a lesser extent, age 3 + fish than in age 1 + fish. In another bully population where parasites were 10 times less abundant, similar effects were noticeable but not significant, whereas no effects of parasites on the responses of galaxiids to predators were apparent. Differences in the abundance of parasites and in their sites of infection in fish may explain the variability among host populations or species. However, in the bully population with high parasite abundance, parasitism has age-dependent effects on responses to predators, providing some support for the prediction that young fish with high expected future reproductive success invest more energy into opposing the effects of parasites than do older fish.     

Control of eutrophication by silver carp (Hypophthalmichthys molitrix) in the tropical Paranoá Reservoir (Brasília,Brazil): a mesocosm experiment

A mesocosm experiment was conducted to assess the impact of moderate silver carp (Hypophthalmichthys molitrix) biomass (41 g m^–3 or 850 kg ha^–1) on the plankton community and water quality of eutrophic Paranoá Reservoir (Brasília, Brazil). Microzooplankton (copepod nauplii and rotifers <200 m), netphytoplankton (> 20 m), total phytoplankton biomass (expressed as chlorophyll-a) and net primary productivity were significantly reduced by silver carp. Apart from increased nitrogen in the sediment, nutrients and chemical properties of the water were not affected by fish presence. The observed improvements in water quality suggest that stocking silver carp in Paranoá Reservoir to control blue-green algae is a promising biomanipulation practice.     

Inhibition of protein tyrosine phosphatase activity by diamide is reversed by epidermal growth factor in fibroblasts.

Diamide (azodicarboxylic acid bis(dimethylamide] inhibits protein tyrosine phosphatase activity in fibroblasts without altering protein tyrosine kinase activity associated with the epidermal growth factor receptor. The loss of protein tyrosine phosphatase activity caused by diamide is reversed by 2-mercaptoethanol or epidermal growth factor.     

Experimental models of maternal–fetal interface and their potential use for nanotechnology applications

During pregnancy, the placenta regulates the transfer of oxygen, nutrients, and residual products between the maternal and fetal bloodstreams and is a key determinant of fetal exposure to xenobiotics from the mother. To study the disposition of substances through the placenta, various experimental models are used, especially the perfused placenta, placental villi explants, and cell lineage models. In this context, nanotechnology, an area of study that is on the rise, enables the creation of particles on nanometric scales capable of releasing drugs aimed at specific tissues. An important reason for furthering the studies on transplacental transfer is to explore the potential of nanoparticles (NPs), in new delivery strategies for drugs that are specifically aimed at the mother, the placenta, or the fetus and that involve less toxicity. Due to the fact that the placental barrier is essential for the interaction between the maternal and fetal organisms as well as the possibility of NPs being used in the treatment of various pathologies, the aim of this review is to present the main experimental models used in studying the maternal–fetal interaction and the action of NPs in the placental environment.     

From endosperm to triploid plants: a stepwise characterization of the de novo shoot organogenesis and morpho-agronomic aspects of an ornamental passion fruit (Passiflora foetida L.)

Plant Cell, Tissue and Organ Culture (PCTOC) - Somaclonal variation during in vitro culture is often an undesirable phenomenon but may also be a source of genetic variation useful for breeders. The...     

Validation of a Dehydroepiandrosterone-Sulfate Assay in Three Platyrrhine Primates (Alouatta caraya,Aotus azarae infulatus,and Sapajus apella)

International Journal of Primatology - The hormone dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are the most abundant circulating steroids in human and some nonhuman primates, and...