131 research outputs found
Synchronous Image-Label Diffusion Probability Model with Application to Stroke Lesion Segmentation on Non-contrast CT
Stroke lesion volume is a key radiologic measurement for assessing the
prognosis of Acute Ischemic Stroke (AIS) patients, which is challenging to be
automatically measured on Non-Contrast CT (NCCT) scans. Recent diffusion
probabilistic models have shown potentials of being used for image
segmentation. In this paper, a novel Synchronous image-label Diffusion
Probability Model (SDPM) is proposed for stroke lesion segmentation on NCCT
using Markov diffusion process. The proposed SDPM is fully based on a Latent
Variable Model (LVM), offering a complete probabilistic elaboration. An
additional net-stream, parallel with a noise prediction stream, is introduced
to obtain initial noisy label estimates for efficiently inferring the final
labels. By optimizing the specified variational boundaries, the trained model
can infer multiple label estimates for reference given the input images with
noises. The proposed model was assessed on three stroke lesion datasets
including one public and two private datasets. Compared to several U-net and
transformer-based segmentation methods, our proposed SDPM model is able to
achieve state-of-the-art performance. The code is publicly available
Relationship between EGFR expression, copy number and mutation in lung adenocarcinomas
<p>Abstract</p> <p>Background</p> <p>This study was designed to investigate EGFR protein expression, EGFR copy number and EGFR mutations in lung adenocarcinomas, to explore the relationship of the three markers.</p> <p>Methods</p> <p>EGFR status was analyzed in surgically resected lung adenocarcinoma samples from 133 Chinese patients by three methods: protein expression (n = 133) by standardized immunohistochemistry (IHC), gene copy number (n = 133) by fluorescence in situ hybridization (FISH), and mutation analysis using the Scorpion amplification refractory mutation system (ARMS) (n = 133).</p> <p>Results</p> <p>The results showed that 68.4% of the samples were positive by IHC, 42.1% were positive by FISH, and 63.9% contained activating kinase domain mutations. EGFR mutations were more frequent in non-smoking patients (p = 0.008), and EGFR mutations were associated with EGFR FISH positivity (p < 0.0001). When using 10% positivity and 2+ as cutoffs, EGFR protein expression was significantly correlated with EGFR FISH positivity (p = 0.012) and EGFR mutations (p = 0.008) after Bonferroni correction.</p> <p>Conclusion</p> <p>EGFR protein expression, EGFR copy number and EGFR mutations were closely related to each other. Standard methods and interpretation criteria need to be established.</p
Intrinsic chemoresistance to gemcitabine is associated with constitutive and laminin-induced phosphorylation of FAK in pancreatic cancer cell lines
<p>Abstract</p> <p>Background</p> <p>One of the major reasons for poor prognosis of pancreatic cancer is its high resistance to currently available chemotherapeutic agents. In recent years, focal adhesion kinase (FAK), a central molecule in extracellular matrix (ECM)/integrin-mediated signaling, has been thought to be a key determinant of chemoresistance in cancer cells. In this study, we aimed to determine the roles of FAK phosphorylation in the intrinsic chemoresistance of pancreatic cancer cell lines.</p> <p>Results</p> <p>Our results showed that, the level of constitutive phosphorylation of FAK at Tyr397 correlated with the extent of intrinsic resistance to Gemcitabine (Gem) in four pancreatic cancer cell lines. Moreover, in Panc-1 cells, which had high expression of pFAK, specific inhibition of constitutive FAK phosphorylation by either RNAi or FRNK overexpression decreased the phosphorylation of Akt, reduced the levels of survivin expression and Bad phosphorylation at Ser136 and increased Gem-induced cytotoxicity and apoptosis. However, in AsPC-1 cells with a low level of pFAK, neither FAK RNAi nor FRNK overexpression affected Gem-induced cell apoptosis. We further found that laminin (LN) induced FAK and Akt phosphorylation in a time-dependent manner, increased the levels of survivin and pBad (pS136) and decreased Gem-induced cytotoxicity and apoptosis in AsPC-1 cells; Specific inhibition of LN-induced FAK phosphorylation by either FAK RNAi or FRNK overexpression suppressed the effects of LN on AsPC-1 cells. Moreover, inhibition of constitutive FAK phosphorylation in Panc-1 cells and LN-induced FAK phosphorylation in AsPC-1 cells by a novel and more specific FAK phosphorylation inhibitor PF-573,228 showed similar results with those of FAK phosphorylation inhibition by FAK RNAi or FRNK overexpression.</p> <p>Conclusions</p> <p>In conclusion, our research demonstrates for the first time that both constitutive and LN-induced FAK phosphorylation contribute to increased intrinsic chemoresistance to Gem in pancreatic cancer cell lines and these effects are partly due to the regulation of Akt and Bad phosphorylation and survivin expression. Development of selective FAK phosphorylation inhibitors may be a promising way to enhance chemosensitivity in pancreatic cancer.</p
Antihyperglycemic and antihyperlipidemic action of cinnamaldehyde in C57blks/j Db/db mice
AbstractObjectiveTo investigate the effects of cinnamaldehyde (CA), an active and major compound in cinnamon, on glucose metabolism and insulin resistance in C57BLKS/J db/db mice.MethodsSixteen male C57BLKS db/db mice were randomly divided into control and CA treatment groups. CA was given (20 mg · kg−1 · day−1, p. o.) for 4 weeks. Pure water was given to control and db/+ mice. Subsequently, the levels of fasting blood glucose (FBG), fasting serum insulin, triglyeride, cholesterol, low-density lipoprotein -cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), and free fatty acids (FFA), as well as the mRNA content of adiponectin and tumor necrosis factor (TNF)-α in adipose tissue, glucose transporter type 4 (GLUT-4) in skeletal muscle, and protein expressions of Akt, phospho-Akt (Thr308), AMPKα, phospho-AMPKα (Thr172) in skeletal muscle were measured.Results1) CA decreased serum levels of FBG and insulin as well as body weight in db/db mice; 2) CA increased serum HDL-C levels; 3) CA significantly decreased the mRNA expression of TNF-α in adipose tissue and upregulated mRNA expression of GLUT-4 in skeletal muscle; 4) protein expression of p-Akt was increased in CA-treated mice, but Akt, AMPKα and p-AMPKα showed no change.ConclusionCA has antihyperglycemic and antihyperlipidemic actions in db/db mice and could be useful in the treatment of type-2 diabetes
Electroacupuncture treatment ameliorates metabolic disorders in obese ZDF rats by regulating liver energy metabolism and gut microbiota
Metabolic disorders represent a major therapeutic challenge to public health worldwide due to their dramatically increasing prevalence. Acupuncture is widely used as adjuvant therapy for multiple metabolic diseases. However, detailed biological interpretation of the acupuncture stimulations is still limited. The gut and the liver are intrinsically connected and related to metabolic function. Microbial metabolites might affect the gut-liver axis through multiple mechanisms. Liver metabolomics and 16S rRNA sequencing were used to explore the specific mechanism of electroacupuncture in treating ZDF rats in this study. Electroacupuncture effectively improved glycolipid metabolism disorders of the ZDF rats. Histopathology confirmed that electroacupuncture improved diffuse hepatic steatosis and hepatocyte vacuolation, and promoted glycogen accumulation in the liver. The treatment significantly improved microbial diversity and richness and upregulated beneficial bacteria that maintain intestinal epithelial homeostasis and decreased bacteria with detrimental metabolic features on host metabolism. Liver metabolomics showed that the main effects of electroacupuncture include reducing the carbon flow and intermediate products in the TCA cycle, regulating the metabolism of various amino acids, and inhibiting hepatic glucose output and de novo lipogenesis. The gut-liver axis correlation analysis showed a strong correlation between the liver metabolites and the gut microbiota, especially allantoin and Adlercreutzia. Electroacupuncture treatment can improve abnormal energy metabolism by reducing oxidative stress, ectopic fat deposition, and altering metabolic fluxes. Our results will help us to further understand the specific mechanism of electroacupuncture in the treatment of metabolic diseases
Spatiotemporal Changes of Reference Evapotranspiration in Mongolia during 1980–2006
Reference evapotranspiration (RET) plays an important role in the terrestrial hydrological cycle. Applying the Penman-Monteith method, the RET over Mongolia was estimated from 1980 to 2006. The changing trends and magnitude of RET were detected by the Mann-Kendall test and Theil-Sen’s slope methods. Meanwhile, aridity indices were estimated using two different indices. The impacts of meteorological variables on RET were assessed through sensitive analysis by comparing the resulting RETs from artificially disturbed meteorological variables. The results indicated that the RET for 16 stations in Mongolia showed an increasing trend, particularly in the center and south. The calculated RET was higher than precipitation, which means severe droughts in Mongolia. The spatial patterns of RET are significantly influenced by climatic conditions as well as characteristics of the underlying surface (e.g., elevation and vegetation). The mean annual RET decreased from the south to the north, owing to sparse vegetation in the south of Mongolia. The sensitivity analysis revealed that the changes of RET were strongly affected by air temperature and relative humidity
Sustainable Crop Protection Using Nematodes (Steinernema Spp) as Biological Control Agents
This research article published by American Scientific Publishers, 2019Crop productions play an important role in food production, raw material production and income generation. Crop production is challenged by pest infestation with new outbreaks every now and then, reducing yield and increasing production cost. The use of biological control agent has been cited as the potential approach in pest management due to the high performing ability with limited effects on the environment and non-targeted organisms. Entomopathogenic nematode is one of the biological control agents used for management of insect pest and it is mostly used in many developed countries with increasing application interest in developing countries. Entomopathogenic formulations from steinernema species (spp) are commercially available, although shipping and stability have been the major challenge. Recently, more than 90 spp. have been isolated from different region and this shows the possibility of having more beneficial strains of steinernema in our surroundings. Research have determined the high performance of entomopathogenic nematode against local insect, this shows the importance of isolating local stain to manage the local pest. On other hands, the different materials have been proven to enhance the pathogenic effect and stability of the nematode when incorporated together and this opens more windows in identifying potential materials for entomopathogenic nematode formulation. Despites some few available challenges of entomopathogenic nematodes applications, it is gaining more attention in agricultural and forest industry due to its broad range of activities and this serves as a potential bio control agent. It is from this view, that this review discussed the potential of Steinernema spp. in crop protection and its performance
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