Immunocytochemical beta-endorphin (beta-EP) staining and ultrastructural observations in the hypothalamus were compared in normal mature female rats, ovariectomized rats, and aged female rats. The ...effects of oestradiol benzoate (EB) on the hypothalamus were studied. The female Wistar rats were divided into seven groups, as follows: 40-day-old rats (Mature), 54-day-old rats ovariectomized at 40 days (Ovx), rats ovariectomized at 40 days and injected with 0.1 mg EB daily for 7 days (Ovx + e) rats ovariectomized and injected with one dose of 1 mg EB (Ovx + E), 500-day-old (Old), old rats injected with 0.1 mg EB daily for 7 days (Old + e), and old rats injected with 1 mg EB (Old + E). In the Ovx and Old groups, beta-EP-positive cells in the arcuate nucleus were rarely seen, as compared with the Mature group. The staining of beta-EP-positive cells in Ovx + e was slightly recovered and that in Ovx + E was almost completely recovered. However, no recovery of beta-EP-positive cells was seen in the Old + e or Old + E groups. The number of nerve fibers in the median eminence were reduced in both the Ovx and Old groups, as compared with the Mature group. There was no relationship between changes in these numbers and oestrogen replacement in the Old group, but in the Ovx group oestrogen replacement brought about recovery of these numbers. The number of glial cells increased after oestrogen replacement in both the Ovx and Old groups. The frequency of giant mitochondria in the neurons in the arcuate nucleus decreased after oestrogen replacement in the Old group.
Stabilized matrix for molten carbonate fuel cell Nirasawa, H.; Kawachi, T.; Ogawa, T. ...
IECEC 96. Proceedings of the 31st Intersociety Energy Conversion Engineering Conference,
1996, Letnik:
2
Conference Proceeding
For commercialization of molten carbonate fuel cell (MCFC) power plants, the most important factors are MCFC performance and life. The performance and life of an MCFC depend on the electrolyte loss ...and gas crossover due to the matrix degradation, such as LiAlO/sub 2/ particle growth during cell operation and the matrix cracking at the initial heat-up stage. In order to suppress the matrix degradation, we fabricated a stabilized matrix with /spl alpha/-LiAlO/sub 2/ as the electrolyte support material and with long /spl alpha/-Al/sub 2/O/sub 3/ fibers as the reinforcement. We assembled the cell with the stabilized matrix. The performance of the cell is stable for 7000 hours. We consider that the matrix degradation, such as the particle growth during cell operation and matrix cracking, has not occurred in this cell.
A phyllodes tumor appeared at the site of a resected fibrocystic disease focus. Administration of danazol resulted in temporary regression, but the tumor resumed growth. Relative hyperestrogenism ...also continued to increase in spite of continued long-term administration of danazol. After 12 months a simple mastectomy was performed. Most of the resected mass consisted of the phyllodes tumor, but it also contained fibrocystic disease.
The tumor-suppressor breast cancer 1 (BRCA1) in complex with BRCA1-associated really interesting new gene (RING) domain 1 (BARD1) is a RING-type ubiquitin E3 ligase that modifies nucleosomal histone ...and other substrates. The importance of BRCA1-BARD1 E3 activity in tumor suppression remains highly controversial, mainly stemming from studying mutant ligase-deficient BRCA1-BARD1 species that we show here still retain significant ligase activity. Using full-length BRCA1-BARD1, we establish robust BRCA1-BARD1-mediated ubiquitylation with specificity, uncover multiple modes of activity modulation, and construct a truly ligase-null variant and a variant specifically impaired in targeting nucleosomal histones. Cells expressing either of these BRCA1-BARD1 separation-of-function alleles are hypersensitive to DNA-damaging agents. Furthermore, we demonstrate that BRCA1-BARD1 ligase is not only required for DNA resection during homology-directed repair (HDR) but also contributes to later stages for HDR completion. Altogether, our findings reveal crucial, previously unrecognized roles of BRCA1-BARD1 ligase activity in genome repair via HDR, settle prior controversies regarding BRCA1-BARD1 ligase functions, and catalyze new efforts to uncover substrates related to tumor suppression.
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•Provide insights into BRCA1-BARD1 ligase regulation and identify a truly inactive mutant•BRCA1-BARD1 E3 ligase activity is critical for DNA end resection•BRCA1-BARD1 E3 ligase contributes to later steps of homologous recombination•Histone ubiquitylation by BRCA1-BARD1 plays an important role in DNA end resection
Wang and Li et al. unveil the intricate regulatory mechanisms of BRCA1-BARD1 ubiquitylation, identify a truly ligase-null variant and another variant specifically impaired in targeting nucleosomal histones, and elucidate the pivotal roles of BRCA1-BARD1 ligase in not only early DNA end resection but also subsequent stages in homology-directed repair.
Oxidative stress with elevated intracellular Ca2+ concentration as well as endothelial dysfunction is a component of pre-eclampsia. Our aim was to investigate the oxidative stress-dependent ...expression of Endoglin and Ca2+-binding S100B protein from villous and amniotic tissue cultures, and to assess sEng expression from S100B protein-stimulated endothelial cells. We initially examined Endoglin and Hydroxy-nonenal-(HNE)-modified proteins in the placentas and amnion obtained from women with pre-eclampsia (n = 8), and healthy controls (n = 8) by immunohistochemistry. To examine oxidative stress and the S100B protein effect on sEng expression from endothelial cells, normal villous and amniotic tissue cultures were stimulated by 4-HNE, sodium fluoride and xanthine/xanthine oxidase, whereas human umbilical vein endothelial cell cultures were treated with S100B protein in a dose- and time-dependent manner at 37°C in an environment of 95% air and 5% of CO2. Culture supernatants were assessed using ELISA. Cell viability was determined using MTS assay. The concentrations of sEng and S100B protein were significantly increased in the villous and amniotic tissue culture supernatants under oxidative stress. S100B protein-stimulated endothelial cells released sEng into conditioned media with a significantly higher expression levels at a concentration of 200 pM–20 nM S100B by 2 h, whereas treated with 200 nM of S100B endothelial cells significantly expressed sEng by 12 h and stimulated the cell proliferation by the same period of time. Our findings show that oxidative stress affects sEng and S100B protein expression from villous and amniotic tissues, and picomolar and low nanomolar concentrations of S100B protein significantly up-regulate sEng release from endothelial cells leading to endothelial dysfunction.
Summary
With ever‐increasing human pressure on ecosystems, it is critically important to predict how ecosystem functions will respond to such human‐induced perturbations. We define perturbations as ...either changes to abiotic environment (e.g. eutrophication, climate change) that indirectly affects biota, or direct changes to biota (e.g. species introductions). While two lines of research in ecology, biodiversity–ecosystem function (BDEF) and ecological resilience (ER) research, have addressed this issue, both fields of research have nontrivial shortcomings in their abilities to address a wide range of realistic scenarios.
We outline how an integrated research framework may foster a deeper understanding of the functional consequences of perturbations via simultaneous application of (i) process‐based mechanistic predictions using trait‐based approaches and (ii) detection of empirical patterns of functional changes along real perturbation gradients. In this context, the complexities of ecological interactions and evolutionary perspectives should be integrated into future research.
Synthesis and applications. Management of human‐impacted ecosystems can be guided most directly by understanding the response of ecosystem functions to controllable perturbations. In particular, we need to characterize the form of a wide range of perturbation–function relationships and to draw connections between those patterns and the underlying ecological processes. We anticipate that the integrated perspectives will also be helpful for managers to derive practical implications for management from academic literature.
Management of human‐impacted ecosystems can be guided most directly by understanding the response of ecosystem functions to controllable perturbations. In particular, we need to characterize the form of a wide range of perturbation–function relationships and to draw connections between those patterns and the underlying ecological processes. We anticipate that the integrated perspectives will also be helpful for managers to derive practical implications for management from academic literature.
Although forest fragmentation has wide-ranging effects on remnant biota and ecosystem functions, the long-term dynamics of fragmented forests is poorly understood. In 2011, we resurveyed eight ...fragments (0.3–8.5 ha) of a Japanese temperate deciduous forest, which was fragmented anthropogenically in the 1940s and 1950s and initially surveyed in 1999, to infer the long-term dynamics of these forest fragments. We compared tree size distributions, aboveground biomass, and community composition over the 12-year period between surveys. We also reconstructed the disturbance history using a dendroecological analysis of tree-ring series. Smaller fragments had a lower density of large trees in 1999, and small-scale disturbance events were estimated to be relatively frequent around the same time that the forest was fragmented. These results were consistent with the expectation that tree mortality would increase following fragmentation. While elevated tree mortality in the small fragments suggests a greater loss of biomass density compared with larger fragments, the aboveground biomass recovered more rapidly in the smaller fragments over the 12-year census interval. However, some small fragments showed extraordinary rates of biomass increases, suggesting that they were not simply the result of a recovery from the fragmentation event, but also reflected recoveries from more recent disturbances. As a result, although the species composition of the smaller fragments approached that of the larger fragments over time, the density of large trees was still lower in the smaller fragments in 2011. Our results emphasize the need to consider such complex forest dynamics when predicting functional consequences of fragmentation.
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