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排序方式: 共有160条查询结果,搜索用时 15 毫秒
31.
Despina Sitara Mohammed S Razzaque Martina Hesse Subbiah Yoganathan Takashi Taguchi Reinhold G Erben Harald Jüppner Beate Lanske 《Matrix biology》2004,23(7):421-432
Fibroblast growth factor-23 (FGF-23), a recently identified molecule that is mutated in patients with autosomal dominant hypophosphatemic rickets (ADHR), appears to be involved in the regulation of phosphate homeostasis. Although increased levels of circulating FGF-23 were detected in patients with different phosphate-wasting disorders such as oncogenic osteomalacia (OOM) and X-linked hypophosphatemia (XLH), it is not yet clear whether FGF-23 is directly responsible for the abnormal regulation of mineral ion homeostasis and consequently bone development. To address some of these unresolved questions, we generated a mouse model, in which the entire Fgf-23 gene was replaced with the lacZ gene. Fgf-23 null (Fgf-23-/-) mice showed signs of growth retardation by day 17, developed severe hyperphosphatemia with elevated serum 1,25(OH)2D3 levels, and died by 13 weeks of age. Hyperphosphatemia in Fgf-23-/- mice was accompanied by skeletal abnormalities, as demonstrated by histological, molecular, and various other morphometric analyses. Fgf-23-/-) mice had increased total-body bone mineral content (BMC) but decreased bone mineral density (BMD) of the limbs. Overall, Fgf-23-/- mice exhibited increased mineralization, but also accumulation of unmineralized osteoid leading to marked limb deformities. Moreover, Fgf-23-/- mice showed excessive mineralization in soft tissues, including heart and kidney. To further expand our understanding regarding the role of Fgf-23 in phosphate homeostasis and skeletal mineralization, we crossed Fgf-23-/- animals with Hyp mice, the murine equivalent of XLH. Interestingly, Hyp males lacking both Fgf-23 alleles were indistinguishable from Fgf-23/-/ mice, both in terms of serum phosphate levels and skeletal changes, suggesting that Fgf-23 is upstream of the phosphate regulating gene with homologies to endopeptidases on the X chromosome (Phex) and that the increased plasma Fgf-23 levels in Hyp mice (and in XLH patients) may be at least partially responsible for the phosphate imbalance in this disorder. 相似文献
32.
Krassimir D. Naydenov Michel K. Naydenov Alexander Alexandrov Kole Vasilevski Veselka Gyuleva Vlado Matevski Biljana Nikolic Venceslas Goudiaby Faruk Bogunic Despina Paitaridou Andreas Christou Irina Goia Christopher Carcaillet Adrian Escudero Alcantara Cengiz Ture Suleyman Gulcu Lorenzo Peruzzi Salim Kamary Srdjan Bojovic Georgi Hinkov Anatoly Tsarev 《Tree Genetics & Genomes》2016,12(4):68
The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260,000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (N st > G st ) typically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The laboratory analysis was performed by fragment analysis—i.e. electrophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individuals as a control. Intense sampling of chloroplast DNA polymorphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (G st(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration histories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest community associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia. 相似文献
33.
Despina Bazou 《Cell biology and toxicology》2010,26(2):127-141
This paper describes the alginate encapsulation of preformed high-density 3-D HepG2 cell aggregates that guarantees good maintenance
of liver-specific biomarker expression. The process involves forming a high-density (≥7 × 104 cells/aggregate) discoid 3-D cell aggregate in an ultrasound trap, which is subsequently recovered and encapsulated in alginate/CaCl2 hydrogel. Glucose secretion/consumption, lactate release, detoxifying enzyme capacity, cytokeratin-18 expression as well
as hypoxia were characterized in encapsulated 3-D HepG2 aggregates over 10 days in culture. Encapsulated 3-D HepG2 aggregates
released glucose into the media, although this ability was exhibited only after 1 day in culture and was subsequently lost
over the ensuing 9 days. In contrast, lactate was constantly released into the media. Significantly more lactate was secreted
after 3 days in culture indicating a more hypoxic environment and hence a higher rate of anaerobic glycolysis. Aggregates
consistently expressed cytokeratin-18. Cytochrome P450-1A1 activity reached a maximum on day 1 of culture followed by a progressive
reduction to basal levels, while P450-3A4 activity was up-regulated in a time-dependent manner reaching a peak on day 7 in
culture. Glutathione-S-transferase activity, on the other hand, was at more physiological levels and remained constant over the 10-day culture period.
The ultrasound trap allowed the rapid (within 5 min) generation of uniformly shaped and sized aggregates. The results reported
here suggest that ultrasound-formed 3-D HepG2 aggregates can serve as alternative in vitro models providing a quick outlook
on toxicity, in a tissue-mimetic manner, thus offering the future option of a cost-effective screening platform for pharmaceutical
development. 相似文献
34.
Hanns-Ulrich Marschall Despina Katsika Curt Einarsson 《Biochemical and biophysical research communications》2010,396(1):58-1412
Gallstone disease is one of the most prevalent gastrointestinal diseases with a substantial burden to health care systems that is expected to increase in ageing populations at risk. This review summarizes recent data on the genetic background of cholesterol gallstones and the role of biliary lipid composition. Three previously unknown non-synonymous mutations in the ABCB4 gene encoding the hepatobiliary phospholipid-flippase MDR3 are presented. 相似文献
35.
36.
Politi EN Lazaris AC Alexopoulou D Lambropoulou S Kavantzas N Koutselini H 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2004,26(4):187-193
OBJECTIVE: To detect argyrophilic nucleolar organizer regions (AgNORs) in ThinPrep (Cytyc Corp., Boxborough, Massachusetts, U.S.A.) liver fine needle aspiration (FNA) specimens and to define the diagnostic value of their quantitative analysis in the evaluation of hepatic lesions. STUDY DESIGN: ThinPrep liquid-based FNA biopsy specimens from 49 malignant and benign liver lesions were resampled, fixed in 95% ethanol and stained with the AgNOR technique in accordance with the 1-step colloid method. The specimens included 11 benign and 38 malignant lesions (23 poorly differentiated hepatocellular carcinomas [HCCs] and 15 poorly differentiated metastatic adenocarcinomas [MCs]). Morphometric analysis was performed using a Zeiss Axiolab microscope (Carl Zeiss GmbH, Jena, Germany) with a mechanical stage fitted with a Sony-iris CCD videocamera (Tokyo, Japan). The videocamera was connected to a Pentium III P/C (Intel Corp., Santa Clara, California, U.S.A.) loaded with the appropriate image analysis software. The measurements were performed with ImageScan software (Jandel Scientific, Erkrath, Germany). The number of AgNORs per nucleus (NN) and the total area per nucleus occupied by AgNORs (AR) were calculated semiautomatically. Statistical analysis was performed using the SPSS software package (Chicago, Illinois, U.S.A.). RESULTS: The least significant deviance test for multiple comparisons revealed that NN differed significantly between the 3 groups of samples examined (P < .0001). The mean NN values in HCCs and MCs were significantly different (P < .0001). Logistic regression model demonstrated that as NN increased, the probability of a MC diagnosis decreased (<4%). AR values were different at a statistically significant level only between benign and malignant specimens (P = .00006), not between HCCs and MCs (P = .933). CONCLUSION: Quantitative analysis of AgNORs in ThinPrep specimens could be a diagnostically useful method in liver disease. 相似文献
37.
Muangmoonchai R Wong SC Smirlis D Phillips IR Shephardl EA 《Molecular biotechnology》2002,20(2):145-151
We describe the delivery of reporter gene constructs to rat liver through the use of the Helios Gene Gun system. The effectiveness
of this transfection method is illustrated by describing its use for determining in vivo the role of a DNA element that regulates
cytochrome P450 2B1 (CYP2B1) gene expression in response to xenobiotics. DNA was delivered to the liver of an anesthetized animal via DNA-coated gold
microcarriers. The highest level of reporter gene expression was obtained about six hours posttransfection; however, at this
time endogenous CYP2B1 mRNA is transiently induced by the anesthetic treatment. The optimal time for investigating expression
of a reporter gene under the control of CYP2B1 regulatory elements was 24 h after transfection, by which time the inductive effect of the anesthetic had ceased. Reporter
gene expression subsequently declined rapidly to a low level by 48 h. In the transfected liver the heterologous SV40 promoter
was about eight-fold stronger than the minimal CYP2B1 promoter. However, when attached to the phenobarbital response element both promoters give the same fold-induction of reporter
activity in response to phenobarbital. 相似文献
38.
Molecular evidence-based use of bone resorption-targeted therapy in prostate cancer patients at high risk for bone involvement 总被引:3,自引:0,他引:3
39.
40.
The epiphytic lichen vegetation of 20 sites around Thessaloniki (Macedonia, northern Greece) surveyed in 1987 was sampled again in 1997 to monitor any changes in lichen communities and consequently in air quality. A general impoverishment in lichen communities was recorded in the 10-year period, presumably chiefly due to changes in the air pollution status. A small increase in lichen species diversity was recorded in some stations, probably as a result of the buffering capacity of airborne dust. 相似文献