首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   60篇
  免费   3篇
  63篇
  2023年   5篇
  2022年   10篇
  2021年   6篇
  2020年   3篇
  2019年   5篇
  2018年   4篇
  2017年   4篇
  2016年   1篇
  2015年   4篇
  2013年   4篇
  2012年   5篇
  2010年   1篇
  2008年   1篇
  2005年   1篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1987年   2篇
  1980年   1篇
  1978年   1篇
排序方式: 共有63条查询结果,搜索用时 0 毫秒
41.
The potential inhibitory effect of the antidiabetic and anti-inflammatory drug, metformin on thioacetamide (TAA)-induced hepatotoxicity associated with the inhibition of mammalian target of rapamycin (mTOR)–hypoxia-inducible factor-1α (HIF-1α) axis has not been investigated before. Therefore, we tested whether metformin can protect against liver injuries including fibrosis induced by TAA possibly via the downregulation of mTOR–HIF-1α axis and profibrogenic and inflammatory biomarkers. Rats either injected with TAA (200 mg/kg; twice a week for 8 weeks) before being killed after 10 weeks (model group) or were pretreated with metformin (200 mg/kg) daily for 2 weeks before TAA injections and continued receiving both agents until the end of the experiment, at Week 10 (protective group). Using light and electron microscopy examinations, we observed in the model group substantial damage to the hepatocytes and liver tissue such as collagen deposition, infiltration of inflammatory cells, and degenerative cellular changes with ballooned mitochondria that were substantially ameliorated by metformin. Metformin also significantly ( p < 0.05) inhibited TAA-induced HIF-1α, mTOR, the profibrogenic biomarker α-smooth muscle actin, tissue inhibitor of metalloproteinases-1, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), alanine aminotransferase (ALT) and aspartate aminotransferase in harvested liver homogenates and blood samples. In addition, a significant ( p < 0.01) positive correlation between hypoxia scoring (HIF-1α) and the serum levels of TNF-α ( r = 0.797), IL-6 ( r = 0.859), and ALT ( r = 0.760) was observed. We conclude that metformin protects against TAA-induced hepatic injuries in rats, which is associated with the inhibition of mTOR–HIF-1α axis and profibrogenic and inflammatory biomarkers; thus, may offer therapeutic potential in humans.  相似文献   
42.
Cell destruction results in plasma accumulation of cell-free DNA (cfDNA). Dynamic changes in circulating lymphocytes are features of COVID-19. We aimed to investigate if cfDNA level can serve in stratification of COVID-19 patients, and if cfDNA level is associated with alterations in lymphocyte subsets and neutrophil-to-lymphocyte ratio (NLR). This cross-sectional comparative study enrolled 64 SARS-CoV-2-positive patients. Patients were subdivided to severe and non-severe groups. Plasma cfDNA concentration was determined by real-time quantitative PCR. Lymphocyte subsets were assessed by flow cytometry. There was significant increase in cfDNA among severe cases when compared with non-severe cases. cfDNA showed positive correlation with NLR and inverse correlation with T cell percentage. cfDNA positively correlated with ferritin and C-reactive protein. The output data of performed ROC curves to differentiate severe from non-severe cases revealed that cfDNA at cut-off ≥17.31 ng/µl and AUC of 0.96 yielded (93%) sensitivity and (73%) specificity. In summary, excessive release of cfDNA can serve as sensitive COVID-19 severity predictor. There is an association between cfDNA up-regulation and NLR up-regulation and T cell percentage down-regulation. cfDNA level can be used in stratification and personalized monitoring strategies in COVID-19 patients.  相似文献   
43.
Brassinosteroids (BRs) have emerged as pleiotropic phytohormone owing to their wide function in crop growth and metabolism. Homobrassinolide (HBR) being an analogue of BRs is known to improve the growth, yield and quality parameters in many crop plants. Thus, an evaluation study was conducted for two years (2018 and 2019) to elucidate the performance of tomato plants (Solanum lycopersicum L.) to a novel group of phytohormone,HBR. The field experiment comprised of seven treatments with homobrassinolide 0.04% (Emulsifiable Concentrate) EC at four different concentrations (0.06, 0.08, 0.10 and 0.12 g active ingredient (a.i.) ha?1) and two well-known growth promoters viz., Gibberellic acid (GA), Naphthalene Acetic Acid (NAA) along with the untreated control. Plant height and chlorophyll concentration were found significantly different in both years of experiment as well as among the different treatments. HBR at 0.12 g a.i. ha?1 was found better with maximum number of fruits (77.36 plant?1), fruit length (6.72 cm), fruit breadth (6.45 cm) and fruit weight (80.52 g) over other concentrations and treatments. Fruit yield was more pronounced in the plots treated with plant growth regulators compared to untreated control. However, significantly higher fruit yield of 91.07 t ha?1 (62.58 t ha?1 with untreated control) along with improved quality traits viz., fruit firmness (4.11 kg cm?2), ascorbic acid content (24.09 mg 100 g?1), total soluble solids (4.43°Brix) and keeping quality (12.50 days) was recorded in 0.12 g a.i. ha?1 HBR treated plots. Thus, it can be inferred that HBRapplication would be a better option to enhance growth, yield as well as quality traits in tomato.  相似文献   
44.
45.

Background

Plasma and urine levels of the potent vasodilator Ang-(1–7) are elevated in mid and late pregnancy and are correlated with elevated placental angiogenesis, fetal blood flow, and rapid fetal growth. We hypothesized that Ang-(1–7), its receptor (Mas1) and the enzymes involved in Ang-(1–7) production (ACE2 and Membrane metallo-endopeptidase; MME) are down regulated in response to glucocorticoid administration contributing to IUGR.

Methods

Pregnant female Sprague–Dawley rats were injected with dexamethasone (DEX; 0.4 mg/kg/day) starting from 14 day gestation (dg) till sacrifice at 19 or 21 dg while control groups were injected with saline (n?=?6/group). The gene and protein expression of ACE2, MME, Ang-(1–7) and Mas1 receptor in the placental labyrinth (LZ) and basal zones (BZ) were studied.

Results

DEX administration caused a reduction in LZ weight at 19 and 21 dg (p?<?0.001). IUGR, as shown by decreased fetal weights, was evident in DEX treated rats at 21 dg (p?<?0.01). ACE2 gene expression was elevated in the LZ of control placentas at 21 dg (p?<?0.01) compared to 19 dg and DEX prevented this rise at both gene (p?<?0.01) and protein levels (p?<?0.05). In addition, Ang-(1–7) protein expression in LZ was significantly reduced in DEX treated rats at 21 dg (p?<?0.05). On the other hand, Mas1 and MME were upregulated in LZ at 21 dg in both groups (p?<?0.05 and p?<?0.001, respectively).

Conclusion

The results of this study indicate that a reduced expression of ACE2 and Ang-(1–7) in the placenta by DEX treatment may be responsible for IUGR and consequent disease programming later in life.
  相似文献   
46.
47.
Developing a suitable applicative process and scaling up the microbial synthesis of nanomaterials is an attractive and emerging prospect for a future sustainable industrial production. In this paper, optimization of fermentation conditions for enhanced production of Co3O4, CuO, Fe3O4, NiO, and ZnO nanoparticles by the endophytic A. terreus ORG-1 was studied. Different cultivation conditions were evaluated. Then, a response surface methodology program was used to optimize physical conditions controlling the biosynthesis of these NPs. Finally, the use of gamma irradiation for improvement of NPs’ production was adopted. Under the optimum conditions and after gamma irradiation, the final yields of the respective NPs reached 545.71, 651.67, 463.19, 954.88, 1356.42 mg L−1. To the best of our knowledge, this is the first report on the production and enhancement of different types of nanomaterials from one microbial culture that can open up the way towards the industrialization of the microbial production of nanomaterials.  相似文献   
48.
Recent years have reported a rise in the occurrence of gastric ulceration especially among young children and adults. This study investigated the mechanism by which two types of Saudi honey: Alnahal Aljawal honey (Wadi) or Bin Ghaithan honey (Talh) exerted their antiulcer potential in indomethacin-induced gastric ulceration. Four cohorts of rats were used: Group 1; Healthy controls, Group 2; Ulcerative animals, Group 3; Ulcerative + Wadi honey treatment, Group 4; Ulcerative + Talh honey treatment. We profiled the levels of different indicators of oxidative stress including the activities of gastric mucosal glutathione superoxide dismutase (SOD), catalase (CAT), peroxidase (GPx), reduced glutathione (GSH), and lipid peroxidation (measured as malondialdehyde; MDA). CRP content, IL-10, and plasma tumor necrosis factor-α were also evaluated. The stomach was visually examined for macroscopic lesions and using light microscope for histopathological changes in the glandular mucosa.Wadi or Talh honey significantly reduced the ulcer indices, and essentially protected the glandular mucosa from lesions. Wadi or Talh honey also significantly reduced the gastric mucosal concentrations of GPx, SOD and GSH. In addition, the administration of Wadi or Talh honey decreased gastric mucosal plasma TNF-α and MDA, CRP content, and IL-10 levels. In conclusion, Wadi or Talh honey possibly exerted their antiulcer potential via restoring the homeostasis and stabilizing the enzymatic (SOD and GPx) and non-enzymatic (GSH) antioxidants as well as reducing the levels of inflammatory cytokines (TNF-α, CRP content, IL-10 and, NF-κB activity), and inhibiting the lipid peroxidation in the gastric mucosa. Consequently, Wadi or Talh honey may be of beneficial therapy for patients diagnosed with gastric ulceration. Clinical studies need to be conducted to further support these findings.  相似文献   
49.
To study the phylogenetics of sugarcane (Saccharum officinarum L.) and its relatives we sequenced four loci on cytoplasmic genomes (two chloroplast and two mitochondrial) and analyzed mitochondrial RFLPs generated using probes for COXI, COXII, COXIII, Cob, 18S+5S, 26S, ATPase 6, ATPase 9, and ATPase (D'Hont et al. 1993). Approximately 650 bp of DNA in the intergenic spacer region between rbcL and atpB and approximately 150 bp from the chloroplast 16S rDNA through the intergenic spacer region tRNAval gene were sequenced. In the mitochondrial genome, part of the 18S rRNA gene and approximately 150 bp from the 18S gene 3 end, through an intergenic spacer region, to the 5S rRNA gene were sequenced. No polymorphisms were observed between maize, sorghum, and Saccharum complex members for the mitochondrial 18S internal region or for the intergenic tRNAval chloroplast locus. Two polymorphisms (insertion-deletion events, indels) were observed within the 18S-5S mitochondrial locus, which separated the accessions into three groups: one containing all of the Erianthus, Eccoilopus, Imperata, Sorghum, and 1 Miscanthus species; a second containing Saccharum species, Narenga porphyrocoma, Sclerostachya fusca, and 1 presumably hybrid Miscanthus sp. from New Guinea; and a third containing maize. Eighteen accessions were sequenced for the intergenic region between rbcL and atpB, which was the most polymorphic of the regions studied and contained 52 site mutations and 52 indels, across all taxa. Within the Saccharum complex, at most 7 site mutations and 16 indels were informative. The maternal lineage of Erianthus/Eccoilopus was nearly as divergent from the remaining Saccharum complex members as it was from sorghum, in agreement with a previous study. Sequences from the rbcL-atpB spacer were aligned with GENBANK sequences for wheat, rice, barley, and maize, which were used as outgroups in phylogenetic analyses. To determine whether limited intra-complex variability was caused by under sampling of taxa, we used seven restriction enzymes to digest the PCR-amplified rbcL-atpB spacer of an additional 36 accessions within the Saccharum complex. This analysis revealed ten restriction sites (none informative) and eight length variants (four informative). The small amount of variation present in the organellar DNAs of this polyploid complex suggests that either the complex is very young or that rates of evolution between the Saccharum complex and outgroup taxa are different. Other phylogenetic information will be required to resolve systematic relationships within the complex. Finally, no variation was observed in commercial sugarcane varieties, implying a world-wide cytoplasmic monoculture for this crop.  相似文献   
50.
Obesity and insulin resistance have been shown to be risk factors for laminitis in horses. The objective of the study was to determine the effect of changes in body condition during the grazing season on insulin resistance and the expression of genes associated with obesity and insulin resistance in subcutaneous adipose tissue (SAT). Sixteen Finnhorse mares were grazing either on cultivated high-yielding pasture (CG) or semi-natural grassland (NG) from the end of May to the beginning of September. Body measurements, intravenous glucose tolerance test (IVGTT), and neck and tailhead SAT gene expressions were measured in May and September. At the end of grazing, CG had higher median body condition score (7 vs. 5.4, interquartile range 0.25 vs. 0.43; P=0.05) and body weight (618 kg vs. 572 kg ± 10.21 (mean ± SEM); P=0.02), and larger waist circumference (P=0.03) than NG. Neck fat thickness was not different between treatments. However, tailhead fat thickness was smaller in CG compared to NG in May (P=0.04), but this difference disappeared in September. Greater basal and peak insulin concentrations, and faster glucose clearance rate (P=0.03) during IVGTT were observed in CG compared to NG in September. A greater decrease in plasma non-esterified fatty acids during IVGTT (P<0.05) was noticed in CG compared to NG after grazing. There was down-regulation of insulin receptor, retinol binding protein 4, leptin, and monocyte chemoattractant protein-1, and up-regulation of adiponectin (ADIPOQ), adiponectin receptor 1 and stearoyl-CoA desaturase (SCD) gene expressions in SAT of both groups during the grazing season (P<0.05). Positive correlations were observed between ADIPOQ and its receptors and between SCD and ADIPOQ in SAT (P<0.01). In conclusion, grazing on CG had a moderate effect on responses during IVGTT, but did not trigger insulin resistance. Significant temporal differences in gene expression profiles were observed during the grazing season.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号