Contrary to the classical mouse inbred strains with unnatural genetic variability, wild-derived strains offer a more suitable model for evolutionary immunology. Toll-like receptors (TLRs) belong to initial detectors of invading pathogens. Although TLRs recognise conserved structures they were shown to be polymorphic. This polymorphism is associated with various diseases. In my thesis, I describe variability of Tlr1, 2 and 6 in 24 inbred strains derived from two subspecies of house mouse (Mus m. musculus and M. m. domesticus). These Tlrs exhibit different levels in variability among the strains. In Tlr1 the polymorphic sites are spread along the whole exodomain. Tlr6 is quite conserved (a lower amount of substitutions located far from the binding region and with minor modifications in the amino acid residue properties). Tlr2, on the contrary, contains some substitutions with substantial alternations of residue properties that are located within or nearby the binding region and the subspecies differ at these sites. All alleles of M. m. domesticus and M. m. musculus, except for Tlr1 PWD, Tlr2 STAIL, are phylogenetically separated. The strains and the subspecies vary in the production of IL-1β, IL-12 a NO after stimulation by TLR1, 2 and 6 ligands. This trend is, however, presumably influenced by the effect of...

No description available.

No description available.

No description available.

No description available.

17 beta-Hydroxy-11 beta(4-dimethylaminophenyl)-17 alpha-(1-propynyl)estra-4, 9-dien-3-one (RU486) inhibited the in vitro development of different stages of mouse preimplantation embryos under study. Two-celled embryos, morulae, and early blastocysts were obtained from B6D2F1 mice. The embryos were grown in Ham F-10 nutrient mixture (with glutamine) supplemented with sodium bicarbonate (2.1 g/L), calcium lactate (282 mg/L), and bovine serum albumin (fraction V, 3 mg/mL) at 37 degrees C in a humidified incubator supplied with 5% CO2 in air. RU486 was added to the culture medium at concentrations of 1, 5, 10, and 20 micrograms/mL. Culture medium with 0.05% ethanol served as the control. In vitro growth of embryos was assessed by the following criteria: (i) two-celled stage embryo development to blastocyst stage after 72 h, (ii) morula stage grown to blastocyst stage after 24 h, and (iii) early blastocyst stage development to hatching blastocyst after 12 h, in culture. RU486 inhibited the in vitro development of two-celled embryos, morulae, and early blastocysts at concentrations of 5, 10, and 20 micrograms/mL culture medium (p less than 0.001). The inhibitory effect of RU486 at these concentrations on the development of all the stages of embryos under study was irreversible. However, RU486 did not affect embryo development at 1 microgram/mL culture medium. The study indicates the direct adverse effect of RU486 at 5 micrograms/mL and higher concentrations in culture medium on the development of mouse preimplantation embryos in vitro, and it encourages its further investigation as a postcoital contraceptive in animal models and humans.

Recent evidence suggests that oxidatively modified forms of low-density lipoprotein (LDL) may be particularly atherogenic. In this investigation, the catabolism of human LDL modified by lipid peroxidation in vitro was studied with a recirculating rat liver perfusion system. A dual-labelling technique was used that permitted native LDL and modified LDL to be studied simultaneously in the liver perfusion system. Native human LDL was found to have a fractional catabolic rate (FCR) of 1.00 +/- 0.21%/h, in agreement with other investigators. Subjecting LDL to oxidation for 12 h in the presence of 30 microM FeEDTA did not significantly affect its FCR. LDL treated with a superoxide-generating system (xanthine oxidase, hypoxanthine, O2) in the presence of 30 microM FeEDTA did, however, show a significant increase in FCR (3.23 +/- 0.19%/h). The hepatic uptakes of native LDL and LDL oxidized with FeEDTA+O2 were similar, but both were significantly lower than the hepatic uptake of LDL treated with the superoxide-radical-generating system. The proteolysis of LDL with pancreatin did not influence either its susceptibility to oxidation or its FCR. LDL oxidation resulted in the preferential loss of alpha-tocopherol rather than gamma-tocopherol. These data indicate that the rat liver effectively catabolizes LDL oxidatively modified by treatment with the superoxide-generating system. Furthermore, our results suggest that only very low plasma levels of highly oxidized LDL could be found under conditions in vivo. The liver may therefore play a major role in protecting the arterial vasculature from highly atherogenic forms of LDL.

This study has determined the cellular site of adenosine deaminase (ADA) expression in the mouse during development from Days 5 through 13 (day vaginal plug was found = Day 0) of gestation. Developmental expression of ADA progressed in two overlapping phases defined genetically (maternal vs. embryonal) and according to region (decidual vs. placental). In the first phase, ADA enzyme activity increased almost 200-fold in the antimesometrial region (decidua capsularis + giant trophoblast cells) from Days 6 through 9 of gestation but remained low in the mesometrial region. Immunohistochemical staining revealed a major localization of ADA to the secondary decidua. In the second phase, ADA activity increased several-fold in the placenta (labyrinth + basal zones) from Days 9 through 13 of gestation but remained low in the embryo proper. Immunohistochemical staining revealed a major localization of ADA to secondary giant cells, spongiotrophoblast, and labyrinthine trophoblast. Regression of decidua capsularis and growth of the spongiotrophoblast population accounted for an antimesometrial to placental shift in both ADA enzyme activity and a 40-kDa immunoreactive protein band. To verify a shift from maternal to fetal expression, studies were performed with two strains of mice (ICR, Eday) homozygous for a different ADA isozyme (ADA-A, ADA-B). Blastocysts homozygous for Adab were transferred to the uterus of pseudopregnant female recipients homozygous for Adaa. The isozymic pattern in chimeric embryo-decidual units analyzed at Days 7, 9, 11, and 13 revealed a predominance of maternal-encoded enzyme at Days 7 through 11 of gestation and a shift to fetal-encoded enzyme by Day 13. Thus, maternal expression of ADA in the antimesometrial decidua may play a role during establishment of the embryo in the uterine environment, whereas fetal expression of ADA in the trophoblast might be important to placentation.

Repeated exposure of the rat vas deferens to the imidazoline oxymetazoline (OXY) results in a progressive loss of response which can appear selective for imidazoline agonists. The present study tests the hypothesis that imidazolines produce desensitization through prolonged blockade or inactivation of alpha-1 adrenoreceptors. Repeated exposure to OXY, naphazoline (NPZ) or tetrahydrozoline (THZ) produces a concentration- and time-dependent rightward shift and depression of the (-)-epinephrine concentration-effect curve, suggesting a mechanism of prolonged receptor blockade or inactivation. (-)-Epinephrine Kd values were similar when estimated after either receptor inactivation with phenoxybenzamine or repeated exposure to imidazolines. The differences in the ability of individual imidazolines to produce desensitization (order of potency: OXY greater than NPZ greater than or equal to THZ) do not follow their intrinsic activity (NPZ approximately THZ approximately OXY) or affinity (OXY greater than or equal to NPZ greater than THZ). The ability of individual imidazoline and phenethylamine agonists to produce a response in imidazoline-desensitized rat vas deferens reflects agonist intrinsic efficacy. Desensitization by imidazoline exposure does not affect contraction produced by either KCl or neurokinin A. Imidazolines produce effects similar to receptor inactivation and their desensitization in vas deferens can be explained without invoking an imidazoline subtype of alpha-1 adrenoreceptor.

No / The molecular identity of ion channels which confer PCO(2)/pH sensitivity in the brain is unclear. Heteromeric Kir4.1/Kir5.1 channels are highly sensitive to inhibition by intracellular pH and are widely expressed in several brainstem nuclei involved in cardiorespiratory control, including the locus coeruleus. This has therefore led to a proposed role for these channels in neuronal CO(2) chemosensitivity. To examine this, we generated mutant mice lacking the Kir5.1 (Kcnj16) gene. We show that although locus coeruleus neurons from Kcnj16((+/+)) mice rapidly respond to cytoplasmic alkalinization and acidification, those from Kcnj16((-/-)) mice display a dramatically reduced and delayed response. These results identify Kir5.1 as an important determinant of PCO(2)/pH sensitivity in locus coeruleus neurons and suggest that Kir5.1 may be involved in the response to hypercapnic acidosis.