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Immature Mice (immature + mouse)
Selected AbstractsAge- and site-specific decline in insulin-like growth factor-I receptor expression is correlated with differential growth plate activity in the mouse hindlimbTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 4 2007Maria A. Serrat Abstract The proximal and distal growth plates of the principal long bones do not contribute equally to longitudinal growth. Most forelimb elongation occurs at the shoulder and wrist, while most hindlimb growth occurs at the knee. This study examined whether insulin-like growth factor-I (IGF-I), a potent growth regulator, could underlie this variation via differential receptor expression. The spatiotemporal distribution of the IGF-I receptor (IGF-IR) was mapped in hindlimb growth plates (overall and within regional zones) from immature mice using immunohistochemistry. Growth activity was assessed by size/morphology of the growth plate and proliferating cell nuclear antigen (PCNA) expression. Both IGF-IR and PCNA staining declined considerably with age in the proximal femur and distal tibia (hip and ankle), but expression remained high in the more active distal femur and proximal tibia (knee) throughout growth. Growth plate size decreased with age in all sites, but the absolute and relative decline in IGF-IR in the hips and ankles of older mice indicated a site-specific loss of IGF-I sensitivity in these less active regions. These results suggest that regulation of the IGF-IR may at least partially mediate differential long bone growth, thereby providing a local mechanism for altering skeletal proportions absent modification of systemic hormone levels. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Mifepristone (Ru486) Antagonizes Monocyte Chemotactic Protein-3 Down-Regulation at Early Mouse Pregnancy Revealing Immunomodulatory Events in Ru486 Induced AbortionAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2004Jaya Nautiyal Problem:, The survival of an embryo bearing the paternal antigens within the immunocompetent environment of the maternal uterus renders ,pregnancy' to be a state of immunological paradox. The ratio of Th1/Th2 responses is crucial for pregnancy maintenance. Monocyte Chemotactic Protein-3 (MCP3) is a pro-inflammatory, CC chemokine and a Th1 effector which is capable of eliciting significant anti-tumoral immune responses. Method of study:, MCP3 expression was investigated in the murine uterine tissue at different days of initial pregnancy and the effect of RU 486 in immature and delayed implantation model studied using Western blotting and Immunocytochemical techniques. Results and conclusion:, Our results show very high uterine MCP3 expression during pre-implantation followed by a significant MCP3 down-regulation at peri-implantation and low levels of MCP3 during post-implantation period. At the peri-implantation stage, embryos exhibited lowered MCP3 expression when compared with the pre-implantation stage. Ru486, a progesterone antagonist when given in a competitive mode with progesterone resulted in a massive surge in MCP3 expression in both immature mice and delayed implantation models. We hypothesize that it is imperative for MCP3 expression to be down-regulated for the success of pregnancy. The cross-talk between Ru486 and amplified MCP3 expression may be one of the mechanisms by way of which RU486 performs its abortificient and anti tumor role. [source] Germ cell apoptosis induced by experimental cryptorchidism is mediated by molecular pathways in mouse testisANDROLOGIA, Issue 1 2010F. Absalan Summary The aim of the study was to characterise the alterations in expression of some apoptosis regulators in unilaterally and bilaterally heat-treated mouse testes at different time intervals to 42 days after surgery. Cryptorchidism was induced in immature mice by returning the testis to the abdominal cavity via a surgical procedure. Transcript levels of Bax, Bcl-2 proper, p53 and survivin mRNA and protein were determined in normal and cryptorchid testes using reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. RT-PCR data verified the elevation of p53 expression and decrease of Bax and Bcl-2 proper mRNA in the cryptorchid testis in a time-dependent manner. The expression of survivin 140 and 40 variants strongly decreased in the bilateral groups compared with unilateral and control groups. These changes were significantly different in the bilateral groups in comparison with the unilateral groups. Immunohistochemistry data showed that the intensity of p53 and Bax expression mainly increased in the remainder cells in the cryptorchid testis and the rates of Bcl-2 proper and survivin expression decreased mainly in the bilateral groups. These observations suggest that multiple molecular pathways participate in the germ cell apoptosis induced by cryptorchidism. [source] Oestrogenic activity of isobutylparaben in vitro and in vivoJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2002P. D. Darbre Abstract The alkyl esters of p -hydroxybenzoic acid (parabens) are used widely as preservatives in foods, pharmaceuticals and cosmetics to which the human population is exposed. Recent studies have reported that methylparaben, ethylparaben, n -propylparaben and n -butylparaben all possess oestrogenic activity in several in vitro assays and in animal models in vivo. This study reports on the oestrogenic activity of isobutylparaben in a panel of assays in vitro and in vivo. Isobutylparaben was able to displace [3H]oestradiol from cytosolic oestrogen receptor , of MCF7 human breast cancer cells by 81% at 100 000-fold molar excess. Using a clonal line of MCF7 cells containing a stably transfected oestrogen-responsive ERE-CAT reporter gene, CAT gene expression could be increased by isobutylparaben such that the magnitude of the response was the same at 10,5 M isobutylparaben as with 10,8 M 17,-oestradiol. Isobutylparaben could also increase expression of the endogenous oestrogen-responsive pS2 gene in MCF7 cells and maximal expression at 10,5 M isobutylparaben could be inhibited with the anti-oestrogen ICI 182 780. The proliferation of two oestrogen-dependent human breast cancer cell lines MCF7 and ZR-75-1 could be increased with isobutylparaben such that at concentrations of 10,5 M the proliferation response was of the same magnitude as with 10,8 M 17,-oestradiol. Evidence for oestrogen receptor mediation of proliferation effects was provided by the inability of isobutylparaben to influence the growth of oestrogen-unresponsive MDA-MB-231 human breast cancer cells and by the ability of the anti-oestrogen ICI 182 780 to inhibit the isobutylparaben effects on MCF7 cell growth. The proliferation response to 10,10 M 17,-oestradiol was not antagonized with isobutylparaben at any concentration from 10,9 M to 10,4 M in either MCF7 or ZR-75-1 cells. Finally, subcutaneous administration of isobutylparaben was able to increase the uterine weight in the immature mouse after three daily doses of 1.2 or 12.0 mg per mouse. Previous work using linear-alkyl-chain parabens has shown that oestrogenic activity increases with alkyl chain length from methylparaben to n -butylparaben. The results here show that branching of the alkyl chain to isobutylparaben increases oestrogenic activity beyond that of the equivalent length linear alkyl chain in n -butylparaben. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||