117,298 research outputs found
Secretion and gene expression of metalloproteinases and gene expression of their inhibitors in porcine corpora lutea at different stages of the luteal phase
No full textWe hypothesize that spontaneous regression of corpora lutea (CL) involves short-lasting restructure of luteal tissue with an activation of matrix metalloproteinases (MMPs) and their respective inhibitors (tissue inhibitors of metalloproteinase, TIMPs). This was tested by determining the gene expression of MMP-1, MMP-2, and MMP-9 and respective TIMP-1 and TIMP-2 in luteal tissue from sows at the early, midluteal, and late luteal phase (Days 6-8, Days 9-11, and Days 13-15 of estrous cycle). Gene expression of the three MMPs was low in early, slightly higher in midluteal, and significantly elevated (P < 0.05) in regressing CL. An inverse pattern was found for gene expression of TIMP-1 and TIMP-2. Under culture conditions, the release of MMPs was determined from steroidogenic large luteal cells (LLC). LLC harvested from regressing CL released significantly (P < 0.05) more active MMPs than cells obtained from CL at the early luteal phase. As luteolysis can be induced by prostaglandin F-2 alpha (PGF(2 alpha)) and tumor necrosis factor alpha (TNF), we studied their effects on LLC under culture conditions. Treatment of cells with PGF(2 alpha) or TNF (10(-7) M or 3 x 10(-9) M, respectively) induced a significantly higher release of MMPs, and gene expression was also significantly stimulated in comparison to that in untreated LLC. The gene expression of TIMPs remained unaffected by either treatment. It is concluded that at the beginning of luteolysis, MMPs are expressed and released in high amounts and that this is essential for the structural regression of the CL
Inhibition of 5 alpha-reductase in the rat prostate by Cimicifuga racemosa
No full textObjectives: Prostate cancers and many thereof derived cell lines, as the LNCaP cells, grow androgen-dependent. In vivo testosterone is locally converted by 5 alpha-reductase to 5 alpha-dihydrotestosterone (5 alpha-DHT) which is the major androgenic principle in prostates and seminal vesicles. The occurrence of prostate cancer and growth of LNCaP cells can be effectively inhibited by finasteride, a synthetic 5 alpha-reductase inhibitor and by a black cohosh (Cimicifuga racemosa, CR) extract. In the present contribution we tested whether the aqueous/ethanolic C. racemosa extract BNO 1055 contains 5u-reductase inhibitors. Methods: Immature 24-day-old mate rats were fed with testosterone (T)-containing food and injected with 30mg CR BNO 1055 or 0.5 mg finasteride for 5 days. Average daily T-uptake was 39 mg/animal. Other animals remained untreated or received vehicle injections only. Results: In comparison to totally untreated rats the testosterone treatment increased weight of prostates and seminal vesicles 3-5-fold and this proliferation was largely and equipotently inhibited by finasteride and CR BNO 1055. 5 alpha-Dihydrotestosterone concentrations in prostate tissue extracts were also reduced by both compounds and the testosterone-upregulated androgen receptor and insulin like growth factor I gene expression inhibited in the seminals vesicles. Conclusion: Taken together, these results indicate that the CR extract BNO 1055 contains one or more potent 5 alpha-reductase inhibitors which may make this extract suitable for the prevention and treatment of prostate cancer and possibly of benign prostate hyperplasia (BPH). (c) 2006 Elsevier Ireland Ltd. All rights reserved
Endothelin-1 (ET-1) release and its gene expression in steroidogenic large luteal cells (LLC) and by luteal fibroblasts (LFB) and the involvement in structural luteolysis of porcine corpora lutea.
No full textEndothelin-1 (ET-1) release and its gene expression in steroidogenic large luteal cells (LLC) and by luteal fibroblasts (LFB) and the involvement in structural luteolysis of porcine corpora lutea.
No full textEffects of estradiol-17 beta, testosterone and a black cohosh preparation on bone and prostate in orchidectomized rats
No full textEstradiol (E,) and testosterone(T) effectively prevent orchidectomy (orx) induced osteoporosis. T, however, Stimulates prostate proliferation which may lead to malignancy. We showed that a Cimicifuga racemosa (CR) preparation had bone-sparing effects without exerting estrogenic effects in the uterus. We Studied therefore whether a CR preparation has also antiosteoporotic effects in orx rats substituted with E-2, T or CR via pelleted food over a period of 3 months. Average daily intake per animal was: T: 25 mg; E-2: 0.325 mg, CR low close: 33 CR high dose: 133 mg, E-2 T and CR a, the high dose partially prevented development of osteoporosis as measured by quantitative computer tomography in the metaphysis of the tibia. E-2, but not T or CR reduced serum osteocalcin and the metabolic products of collagen-1 alpha 1. Gene expression of collagen-1 alpha 1 and tartrate-resistant acid phosphatase was decreased by E-2 and the higher dose of the CR extract but increased in the T-treated animals. In the prostate T inhibited androgen receptor, estrogen receptor alpha and insulin-like growth factor-1 gene expression but Stimulated the expression of the ERP gene. These effects were not shared by E-2 or both doses of the CR extract. It is concluded that E-2 T and CR exert antiosteoporotic effects in the metaphysis of the tibia of orx rats. T has profound effects in the prostate which were not seen in the E-2- and CR-treated animals. Therefore, the Cimicifuga racemosa extract BNO 1055 may be useful to prevent osteoporosis in aged male patients with reduced testosterone production. (c) 2004 Elsevier Ireland Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
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