Metric-Based Assessment Method for MS-T Formalism with Small Subsets of Torsional Conformers.

The multi-structural approximation with torsional anharmonicity (MS-T) method and its variants have been widely used for calculating conformational-rovibrational partition functions of large molecules. The present work aimed to propose a systematic method to assess and explain the performance of various variants of the MS-T method. First, we proposed the simplest variant MS-T(2NN) (two nearest neighborhood torsions are coupled) and systematically validated it for large alkanes n-CnH2n+2 (n = 6-10) and their transition states of hydrogen abstraction reactions. Second, we proposed a metric-based method to explain the underlying reason for the good performance of MS-T(2NN)─it includes the torsional conformers that have dominant contributions to the partition function calculations. These conformers are closer to the lowest-energy conformer in the space of dihedral and energy metrics. Third, the same observation and explanation apply to the other two variants, MS-2DT (any two torsions are coupled) and MS-3DT (any three torsional are coupled), which contain increasingly more torsional conformers than MS-T(2NN) but are subsets of the complete set of torsional conformers considered by the MS-T method. Overall, the present method provides a mathematically rigorous and computationally effective diagnosis tool to assess various MS-T methods dealing with the torsional anharmonicity of large molecules in the partition function calculation.

Plasma Cell Myeloma Mimicking Metastatic Carcinoma with CD138 positivity: a Potential Diagnostic Pitfall.

BACKGROUND: Plasma cell myeloma is a kind of multifocal proliferation of neoplastic plasma cells in bone marrow. Morphology of myeloma plasma cells varies from mature to immature form, plasmablastic, and pleomorphic cells, with the proportion of plasma cells changing from a slight increase to > 90%. Several morphologic variants of PCM have been reported. METHODS: Herein, we present a rare case of PCM with typical morphological features of bone marrow metastatic carcinoma, association with CD138 positivity, and a complex karyotype. RESULTS: The diagnosis of PCM was made based on a combination of the clinical features, morphology, immunofixation electrophoresis, flow cytometry immunophenotyping, and bone marrow biopsy. Overall, the result was in accord with PCM based on the WHO classification. CONCLUSIONS: The case focuses on the wide morphological variants of PCM and highlights the reason why PCM should be taken as a differential diagnosis when one presents with typical morphological feature and common antigens expression of bone marrow metastatic carcinoma.

Universality in the viscous-to-inertial coalescence of liquid droplets.

We present a theory on the coalescence of 2 spherical liquid droplets that are initially stationary. The evolution of the radius of a liquid neck formed upon coalescence was formulated as an initial value problem and then solved to yield an exact solution without free parameters, with its 2 asymptotic approximations reproducing the well-known scaling relations in the inertially limited viscous and inertial regimes. The viscous-to-inertial crossover observed in previous research is also recovered by the theory, rendering the collapse of data of different viscosities onto a single curve.

Scaled recoupling of chemical shift anisotropies at high magnetic fields under MAS with interspersed C-elements.

The power of chemical shift anisotropy (CSA) measurements for probing structure and dynamics of molecules has been long recognized. NMR pulse sequences that allow measurement of CSA values in an indirect dimension of a protein correlation spectrum have been employed for aliphatic groups, but for practical reasons, carbonyl functional groups have been little studied, despite the fact that carbonyls are expected to give particularly varied and informative CSA values. Specifically, the wide spectral widths of carbonyl tensors make their measurements difficult with typically attainable spectrometer settings. We present here an extended family of experiments that enable the recovery of static CSA lineshapes in an indirect dimension of magic angle spinning (MAS) solid-state NMR experiments, except for various real valued scaling factors. The experiment is suitable for uniformly labeled material, at moderate MAS rates (10 kHz-30 kHz) and at higher magnetic fields (ν0H > 600 MHz). Specifically, the experiments are based on pulse sequence elements from a previous commonly used pulse sequence for CSA measurement, recoupling of chemical shift anisotropy (ROCSA), while modification of scaling factors is achieved by interspersing different blocks of C-elements of the same Cnn 1 cycle. Using experimental conditions similar to the parent ROCSA sequence, a CSA scaling factor between 0 and 0.272 can be obtained, thus allowing a useful practical range of possibilities in experimental conditions for measurement of larger CSA values. Using these blocks, it is also possible to make a constant-time CSA recoupling sequence. The effectiveness of this approach, fROCSA, is shown on model compounds 1-13C-Gly, U-13C,15N-l-His, and microcrystalline U-13C,15N-Ubiquitin.

Ganoderma lucidum polysaccharide inhibits the proliferation of leukemic cells through apoptosis.

OBJECTIVE: To investigate the cytotoxic effect of polysaccharides derived from Ganoderma lucidum on T lymphocyte leukemia cells. METHODS: Water-soluble polysaccharides were extracted from the fruit bodies of G. lucidum, purified, and characterized using HPGPC-MALLS and NMR. The cytotoxicity of G. lucidum polysaccharide fraction 5 (GLP5) to T lymphocyte leukemia cell line Jurkat and human immortalized epidermal cell line HaCat was assessed using MTT assay. Apoptosis was assessed using flow cytometry. Expressions of apoptosis-related genes in the cells after being exposed to GLP5 were detected using Western blot assay. RESULTS: GLP5 was a ß-(1→3) and ß-(1→6) linked glucan. It inhibited the proliferation of Jurkat cells in a concentration-dependent manner and the half-maximal inhibitory concentration (IC50) was 34.5 mg/L but did not suppress the growth of HaCat cells. Apoptotic cells in Jurkat cells were detected to increase with increasing GLP5 concentrations. The expression levels of cleaved caspase-3 were significantly higher after the cells were exposed to 25 and 50 mg/L GLP5 when compared to non-exposed cells (Control). In addition, the expression levels of BAX and Bcl2 were significantly up- and down-regulated after treatment with GLP5 at 25 and 50 mg/L when compared with control (P<0.05), respectively. CONCLUSIONS: GLP5 has antiproliferative activity against Jurkat cells and the activity is likely mediated through the activation of apoptosis pathways.

Genome-wide identification of soybean Shaker K+ channel gene family and functional characterization of GmAKT1 in transgenic Arabidopsis thaliana under salt and drought stress.

Potassium is a major cationic nutrient involved in numerous physiological processes in plants. The uptake of K+ is mediated by K+ channels and transporters, and the Shaker K+ channel gene family plays an essential role in K+ uptake and stress resistance in plants. However, little is known regarding this family in soybean. In this study, 14 members of the Shaker K+ channel gene family were identified in soybean and were classified into five groups. Protein domain analysis revealed that Shaker K+ channel gene members have an ion transport domain (ion trans), a cyclic nucleotide-binding domain, ankyrin repeat domains, and a dimerization domain in the potassium ion channel. Quantitative real-time polymerase chain reaction analysis indicated that the expression of eight genes (notably GmAKT1) in soybean leaves and roots was significantly increased in response to salt and drought stress. Furthermore, the overexpression of GmAKT1 in Arabidopsis enhanced root length, K+ concentration, and fresh/dry weight ratio compared with wild-type plants subjected to salt and drought stress; this suggests that GmAKT1 improves the tolerance of soybean to abiotic stress. Our results provide important insight into the characterization of Shaker K+ channel gene family members in soybean and highlight the function of GmAKT1 in soybean plants under salt and drought stress.

Nucleic Acid Vaccine Targeting Nogo-66 Receptor and Paired Immunoglobulin-Like Receptor B as an Immunotherapy Strategy for Spinal Cord Injury in Rats.

Nogo-66 receptor (NgR) and paired immunoglobulin-like receptor B (PirB) are two common receptors of various myelin-associated inhibitors (MAIs) and, thus, play an important role in MAIs-induced inhibitory signalling of regeneration following spinal cord injury (SCI). Based on the concept of protective autoimmunity, vaccine approaches could induce the production of antibodies against inhibitors in myelin, such as using purified myelin, spinal cord homogenates, or MAIs receptor NgR, in order to block the inhibitory effects and promote functional recovery in SCI models. However, due to the complication of the molecules and the mechanisms involved in MAIs-mediated inhibitory signalling, these immunotherapy strategies have yielded inconsistent outcomes. Therefore, we hypothesized that the choice and modification of self-antigens, and co-regulating multiple targets, may be more effective in repairing the injured spinal cord and improving functional recovery. In this study, NgR and PirB were selected to construct a double-targeted granulocyte-macrophage colony stimulating factor-NgR-PirB (GMCSF-NgR-PirB) nucleic acid vaccine, and investigate the efficacy of this immunotherapy in a spinal cord injury model in rats. The results showed that this vaccination could stimulate the production of antibodies against NgR and PirB, block the inhibitory effects mediated by various MAIs, and promote nerve regeneration and functional recovery after spinal cord injury. These findings suggest that nucleic acid vaccination against NgR and PirB can be a promising therapeutic strategy for SCI and other central nervous system diseases and injuries.

Inhibition of extracellular signal-regulated kinase activity by sorafenib increases sensitivity to DNR in K562 cells.

The mitogen-activated protein kinase (MAPK) pathway has a protective function on the management of hematologic malignancies. The aim of this study was to assess whether the induction of MAPK-mediated effects contributes to the therapeutic value of combination sorafenib and daunorubicin (DNR) treatment. Herein, we found that DNR increased phosphorylation of extracellular signal-regulated kinases (ERK1/2) in K562 cells. ERK1/2 activity was blocked by either the mitogen-induced extracellular kinase (MEK) inhibitor U0126 or a multi-kinase inhibitor sorafenib. Of note, sorafenib sensitized K562 to DNR by inhibiting proliferation and inducing apoptosis in a dose-dependent manner which was through blocking the RAF/MEK/ERK pathway. Moreover, K562 cells transfected with a constitutively active MEK2DD plasmid showed increasing IC50 values following DNR treatment compared with control cells. Combination of DNR with MEK inhibitor U0126 synergistically inhibited K562 cell growth. In conclusion, our results indicated that sorafenib sensitized K562 cells to DNR-induced cytotoxicity by downregulating p-ERK1/2 expression. DNR in combination with sorafenib may represent a new and potential therapeutic strategy in treating acute leukemia with high p-ERK1/2 levels.

[Sorafenib induces apoptosis of U937 cells via inhibiting WNT signal pathway].

This study was aimed to investigate the effect of multikinase inhibitor sorafenib on the proliferation and apoptosis of U937 cells and its possible mechanism. U937 cells were treated with different concentrations of sorafenib for 48 hours. Cell viability was determined by Cell Counting Kit-8; cell apoptosis and cell ratio in cell cycle were detected by flow cytometry with Annexin V/PI staining and PI staining respectively; expressions of GSK-3ß, ß-catenin and cyclin-D1 were assayed by Western blot. The results showed that the proliferation of U937 cells was inhibited by sorafenib in a dose-dependent manner (p < 0.05). Sorafenib induced cell apoptosis and cell cycle G(1)/G(0) arrest. Compared with results of Western blot before treatment, expression of inactivated GSK-3ß, ß-catenin and Cyclin-D1 down-regulated in a dose-dependent manner after treatment with sorafenib, this same changes were observed after up-regulation of inactivated GSK-3ß by LiCl (p < 0.05). It is concluded that sorafenib inhibits the proliferation of U937 cells and induces cell apoptosis through reducing negative regulation of WNT signal pathway on inactivated GSK-3ß and down-regulating ß-catenin and cyclin-D1 level, which result in U937 cell cycle G(1)/G(0) arrest.

[Effect of sorafenib combined with daunorubicin on K562 cell line].

The aim of this study was to investigate the effect of sorafenib combined with daunorubicin on leukemic k562 cell line. The inhibitory effect of sorafenib alone and its combination with daunorubicin on K562 cell proliferation was detected by MTT method; the synergistic effect was measured by CDI (coefficient of drug interaction); the apoptosis of K562 cells was observed by flow cytometry with Hoechst 33258 staining. The results showed that the sorafenib alone or its combination with daunorubicin could significantly inhibit K562 cell proliferation and the combination of both drugs displayed synergistic effect on K562 cells, meanwhile the apoptotic cells increased. It is concluded that the combination of sorafenib and daunorubicin has a obviously synergistic inhibitory effect on leukemic cell line K562.