A reversed phase HPLC method for the analysis of nucleotides to determine 5’-PDE enzyme activity

5’-Phosphodiesterase (5'-PDE) can be extracted from barley roots and used as a catalyst in the hydrolysis of RNA to produce 5'-nucleotides. The assay of enzyme activity is essential for the production of 5'-PDE. To improve the conventional assays, we developed and validated a new method for the analysis of 5’-PDE enzyme activity using reversed phased high performance liquid chromatography (RP-HPLC). The method is based on the quantification of the four 5’-nucleotides namely cytidine 5’-monophosphate (5’-CMP), uridine 5’-monophosphate (5’-UMP), guanosine 5’-mono-phosphate (5’-GMP) and adenosine 5’-mono-phosphate (5’-AMP), produced in the enzymatic hydrolysis of yeast RNA. The optimal condition for the enzymatic hydrolysis of RNA to detect the enzyme activity was investigated. The results show that when the hydrolysis takes place at 70 oC for 30 min at pH 5.0, the hydrolysis reaction has highest yield for the four of the 5’-nucleotides. 5’-PDE demonstrated highest catalytic capability. These four 5’-nucleotides were utilized for the analysis of enzyme activity of 5’-PDE with our newly developed HPLC method. Excellent reproducibility, precision, and linearity were obtained for this HPLC method. KEY WORDS: Enzyme activity, 5’-PDE, Barley roots, Nucleotides, RNABull. Chem. Soc. Ethiop. 2010, 24(2), 167-174

PET-CT Principles and Applications in Lung Cancer Management

Lung cancer is the most common malignant cancer throughout the world; the positron emission tomography/computed tomography (PET-CT) combines both the metabolism information from PET and anatomy details from CT, which is the state of the art. This manuscript introduced the PET-CT and applications in lung cancer diagnosing, staging, and treatment. Several aspects including clinical features, classification, grading and pathology of the lung cancer, principles of PET-CT, and evaluation of diagnosing and treatment had been covered. Detailed demonstration of each cancer subtype, staging criteria, and classification was described. The content will benefit the clinical doctors as well as radiologists

Identification of key bioactive anti-migraine constituents of Asari radix et rhizoma using network pharmacology and nitroglycerin-induced migraine rat model

Purpose: To elucidate the bioactive constituents of Asari radix et rhizoma (ARR) in treating migraine based on network pharmacology and nitroglycerin-induced migraine rat model. Methods: The potential bioactive constituents of ARR were identified with the aid of literature retrieval and virtual screening, and the migraine-related hub genes were identified using protein-protein interaction and topology analyses. Then, the interaction between the potential bioactive constituents and hub genes was determined with molecular docking and topology, leading to the prediction of the anti-migraine constituents of ARR. Moreover, a rat model of nitroglycerin-induced migraine was used to confirm the prediction by measuring the frequency of head-scratching and head-shaking behavior (FHHB) in the rats. In addition, levels of nitric oxide (NO) and calcitonin gene-related peptide (CGRP) in blood, norepinephrine (NE) and 5-hydroxytryptamine (5-HT) in brain were measured using appropriate commercial kits. Results: Network pharmacology revealed that naringenin-7-O-β-D-glucopyranoside and higenamine might be the key anti-migraine bioactive constituents of ARR. On addition of naringenin-7-O-β-D- glucopyranoside or higenamine to ARR, there was marked enhancement of the mitigating effect of ARR on nitroglycerin-induced abnormalities in levels of NO, CGRP, 5-HT and NE, as well as FHHB in rats (p < 0.05 or 0.01). Conclusion: These findings indicate that naringenin-7-O-β-D-glucopyranoside and higenamine might be the key bioactive and anti-migraine constituents of ARR. However, in addition to naringenin-7-O-β-D- glucopyranoside and higenamine, there were many other anti-migraine constituents in ARR. Therefore, there is need for further investigations on the actual contributions of these two constituents of ARR in treating migraine

Portable Intelligent Oscilloscope Based on Innovative Education

Based on the innovative education idea that students in various universities can do experiments anytime and anywhere without being limited by the course time, a portable oscilloscope suitable for students' experiment and teaching practice is designed by using Arduino, Android and Bluetooth Technology. This oscilloscope not only realizes the basic functions of an oscilloscope, but also makes the measurement images of low-frequency signals more clear and impressive. In addition, the design based on the mobile App is more user-friendly, which enhances the user's sense of use and facilitates the sorting and query of experimental data. The application test shows that the oscilloscope has stable performance, clear waveform, satisfies students' learning and teaching practice to a large extent, and has a good development prospect

Quality test of clamping connection of transmission lines across tensile line

This paper develops a new technology for the quality inspection of the transmission line that is important across the tensile clamp. The new technology mainly based on the ultrasonic pulse echo thickness measurement mechanism tests the thickness of the aluminum sleeve after crimping the tensile clamp to reflect the relative position of the aluminum sleeve and the steel anchor after the crimping, thereby judging whether there is a crimping positioning defect. At the same time, it is supplemented by steel anchor model comparison, crimping position length comparison, and crimping to margin detection to determine whether the transmission line crimping quality is qualified

The Prognostic Significance of Apoptosis-Related Biological Markers in Chinese Gastric Cancer Patients

BACKGROUND AND OBJECTIVE: The prognosis varied among the patients with the same stage, therefore there was a need for new prognostic and predictive factors. The aim of this study was to evaluate the relationship of apoptosis-related biological markers such as p53, bcl-2, bax, and c-myc, and clinicopathological features and their prognostic value. METHODS: From 1996 to 2007, 4426 patients had undergone curative D2 gastrectomy for gastric cancer at Fudan University Shanghai Cancer Center. Among 501 patients, the expression levels of p53, bcl-2, bax, and c-myc were examined by immunohistochemistry. The prognostic value of biological markers and the correlation between biological markers and other clinicopathological factors were investigated. RESULTS: There were 339 males and 162 females with a mean age of 57. The percentages of positive expression of p53, bcl-2, bax, and c-myc were 65%, 22%, 43%, and 58%, respectively. There was a strong correlation between p53, bax, and c-myc expression (P=0.00). There was significant association between bcl-2, and bax expression (P<0.05). p53 expression correlated with histological grade (P=0.01); bcl-2 expression with pathological stage (P=0.00); bax expression with male (P=0.02), histological grade (P=0.01), Borrmann type (P=0.01), tumor location (P=0.00), lymph node metastasis (P=0.03), and pathological stage (P=0.03); c-myc expression with Borrmann type (P=0.00). bcl-2 expression was related with good survival in univariate analysis (P=0.01). Multivariate analysis showed that bcl-2 expression and pathological stage were defined as independent prognostic factors. There were significant differences of overall 5-year survival rates according to bcl-2 expression or not in stage IIB (P=0.03). CONCLUSION: The expression of bcl-2 was an independent prognostic factor for patients with gastric cancer; it might be a candidate for the gastric cancer staging system

Lipid raft/caveolae signaling is required for Cryptococcus neoformans invasion into human brain microvascular endothelial cells

<p>Abstract</p> <p>Background</p> <p><it>Cryptococcus neoformans </it>has a predilection for central nervous system infection. <it>C. neoformans </it>traversal of the blood brain barrier, composed of human brain microvascular endothelial cells (HBMEC), is the crucial step in brain infection. However, the molecular mechanism of the interaction between <it>Cryptococcus neoformans </it>and HBMEC, relevant to its brain invasion, is still largely unknown.</p> <p>Methods</p> <p>In this report, we explored several cellular and molecular events involving the membrane lipid rafts and caveolin-1 (Cav1) of HBMEC during <it>C. neoformans </it>infection. Immunofluorescence microscopy was used to examine the roles of Cav1. The knockdown of Cav1 by the siRNA treatment was performed. Phosphorylation of Cav1 relevant to its invasion functions was investigated.</p> <p>Results</p> <p>We found that the host receptor CD44 colocalized with Cav1 on the plasma membrane, and knockdown of Cav1 significantly reduced the fungal ability to invade HBMEC. Although the CD44 molecules were still present, HBMEC membrane organization was distorted by Cav1 knockdown. Concomitantly, knockdown of Cav1 significantly reduced the fungal crossing of the HBMEC monolayer <it>in vitro</it>. Upon <it>C. neoformans </it>engagement, host Cav1 was phosphorylated in a CD44-dependent manner. This phosphorylation was diminished by filipin, a disrupter of lipid raft structure. Furthermore, the phosphorylated Cav1 at the lipid raft migrated inward to the perinuclear localization. Interestingly, the phospho-Cav1 formed a thread-like structure and colocalized with actin filaments but not with the microtubule network.</p> <p>Conclusion</p> <p>These data support that <it>C. neoformans </it>internalization into HBMEC is a lipid raft/caveolae-dependent endocytic process where the actin cytoskeleton is involved, and the Cav1 plays an essential role in <it>C. neoformans </it>traversal of the blood-brain barrier.</p

Heisenberg-limited spin squeezing in coupled spin systems

Spin squeezing plays a crucial role in quantum metrology and quantum information science. Its generation is the prerequisite for further applications but still faces an enormous challenge since the existing physical systems rarely contain the required squeezing interactions. Here we propose a universal scheme to generate spin squeezing in coupled spin models with collective spin-spin interactions, which commonly exist in various systems. Our scheme can transform the coupled spin interactions into squeezing interactions, and reach the extreme squeezing with Heisenberg-limited measurement precision scaling as $1/N$ for $N$ particles. Only constant and continuous driving fields are required, which is accessible to a series of current realistic experiments. This work greatly enriches the variety of systems that can generate the Heisenberg-limited spin squeezing, with broad applications in quantum precision measurement

Control of absorption of monolayer MoS2_{2} thin-film transistor in one-dimensional defective photonic crystal

The light absorption and transmission of monolayer MoS$_{2}$ in a one-dimensional defective photonic crystal (d-1DPC) is theoretically investigated. The study shows that the strong interference effect decreases photon density in particular areas of the microcavity. The d-1DPC can reduce light absorption of monolayer MoS$_{2}$ and enhance light transmission. The impact of monolayer MoS$_{2}$ light absorption on the localization effect of photon is investigated when monolayer MoS$_{2}$ and the organic light-emitting diode are located in the same microcavity. However, monolayer MoS$_{2}$ does not reduce the localization effect of light by regulating the position of monolayer MoS$_{2}$ in the microcavity.Comment: 5pages,5figure