Human immunodeficiency virus type 1 specific cytotoxic T lymphocyte responses in Chinese infected with HIV-1 B'/C Recombinant (CRF07_BC)

<p>Abstract</p> <p>Background</p> <p>The characterization of HIV-1-specific T cell responses in people infected with locally circulating HIV-1 strain will facilitate the development of HIV-1 vaccine. Sixty intravenous drug users infected with HIV-1 circulating recombinant form 07_BC (CRF07_BC), which has been spreading rapidly in western China from north to south, were recruited from Xinjiang, China to assess the HIV-1-specific T cell responses at single peptide level with overlapping peptides (OLP) covering the whole concensus clades B and C proteome.</p> <p>Results</p> <p>The median of the total magnitude and total number of OLPs recognized by CTL responses were 10925 SFC/million PBMC and 25 OLPs, respectively, when tested by clade C peptides, which was significantly higher than when tested by clade B peptides. The immunodominant regions, which cover 14% (58/413) of the HIV-1 proteome, are widely distributed throughout the HIV-1 proteome except in Tat, Vpu and Pol-PR, with Gag, Pol-RT, Pol-Int and Nef being most frequently targeted. The subdominant epitopes are mostly located in p24, Nef, integrase, Vpr and Vif. Of the responses directed to clade C OLPs, 61.75% (972/1574) can be observed when tested with corresponding clade B OLPs. However, Pol-PR and Vpu tend to be targeted in the clade B sequence rather than the clade C sequence, which is in line with the recombinant pattern of CRF07_BC. Stronger and broader CTL responses in subjects with CD4 cell counts ranging from 200 to 400/mm³were observed when compared to those with less than 200/mm³or more than 400/mm³, though there have been no significant correlations identified between the accumulative CTL responses or overall breadth and CD4 cell count or plasma viral load.</p> <p>Conclusion</p> <p>This is the first study conducted to comprehensively address T cell responses in Chinese subjects infected with HIV-1 CRF07_BC in which subtle differences in cross-reactivity were observed, though similar patterns of overall immune responses were demonstrated with clade B infected populations. The immunodominant regions identified in this population can facilitate future HIV-1 vaccine development in China.</p

Scaling Dynamic Response and Destructive Metabolism in an Immunosurveillant Anti-Tumor System Modulated by Different External Periodic Interventions

On the basis of two universal power-law scaling laws, i.e. the scaling dynamic hysteresis in physics and the allometric scaling metabolism in biosystem, we studied the dynamic response and the evolution of an immunosurveillant anti-tumor system subjected to a periodic external intervention, which is equivalent to the scheme of a radiotherapy or chemotherapy, within the framework of the growth dynamics of tumor. Under the modulation of either an abrupt or a gradual change external intervention, the population density of tumors exhibits a dynamic hysteresis to the intervention. The area of dynamic hysteresis loop characterizes a sort of dissipative-therapeutic relationship of the dynamic responding of treated tumors with the dose consumption of accumulated external intervention per cycle of therapy. Scaling the area of dynamic hysteresis loops against the intensity of an external intervention, we deduced a characteristic quantity which was defined as the theoretical therapeutic effectiveness of treated tumor and related with the destructive metabolism of tumor under treatment. The calculated dose-effectiveness profiles, namely the dose cumulant per cycle of intervention versus the therapeutic effectiveness, could be well scaled into a universal quadratic formula regardless of either an abrupt or a gradual change intervention involved. We present a new concept, i.e., the therapy-effect matrix and the dose cumulant matrix, to expound the new finding observed in the growth and regression dynamics of a modulated anti-tumor system

Changes in some chemical components and in the physiology of rambutan fruit (

Introduction. Rambutan (Nephelium lappaceum L.) is a kind of tropical fruit with high commercial value in international trade. However, harvested rambutan fruits suffer from a short shelf life and show rapid postharvest deterioration problems due to spintern browning and flesh decay. Materials and methods. Rambutan fruit (cv. ‘Baoyan 5’) were harvested in 2009 and 2010. Changes in some chemical components and the physiology of fruits were investigated at different storage temperatures (25 °C and 10 °C) and with different packing materials (regular low-density polyethylene and anti-moisture polyethylene bags). Results and discussion. Changes in the development of the browning index, and contents of total soluble solids, titratable acidity and vitamin C greatly decreased during low temperature storage (10 °C); moreover, low temperature storage (10 °C) could maintain a significantly higher level of superoxide dismutase activity and lower values of malondialdehyde and cell membrane permeability. The effects of packing material were different according to the different storage temperatures. At 10 °C, the beneficial effects of anti-moisture polyethylene bags on fruit quality and physiology were observed. However, at 25 °C, fruit packed with regular low-density polyethylene proved to be of better quality than those packed with anti-moisture polyethylene bags. Conclusion. The overall results suggest that packing with anti-moisture polyethylene bags and storage at 10 °C were the most suitable conditions to maintain quality and to extend the storage life of rambutan fruit

Comparative Analyses of Ripening, Texture Properties and Cell Wall Composition in Three Tropical Fruits Treated with 1-Methylcyclopropene during Cold Storage

Regulation of fruit ripening is one of the most important topics in postharvest storage. Effects of 1-methylcyclopropene (1-MCP) greatly depend on the responsiveness of fruit cultivar to this molecule. Although 1-MCP has been used in postharvest preservation of many fruit species, its effects on ripening process, including ethylene production, and softening of banana, mango, and papaya are still not very clear. In the present study, we comparatively investigated the effects of 1-MCP fumigation treatment (1 μL L−1 for 20 h) on ripening behavior and texture qualities of the three fruits during storage at 15 °C. Results showed that 1-MCP treatment not only suppressed the production but also delayed the peak points of ethylene in banana and mango. However, it only significantly delayed the emergence of peak, but didn’t suppress the production of ethylene in papaya. Meanwhile, 1-MCP treated papayas showed the lowest malondialdehyde (MDA) content, cell membrane permeability (CMP) and activities of polygalacturonase (PG) and cellulose (CX), accompanied by the highest firmness and protopectin content. Furthermore, 1-MCP treatment slowed down the changes of pulp cell structure in three kinds of fruit. Thus, the findings suggest that postharvest application of 1-MCP has potential in banana and mango fruits due to both prolonging storage-life and ensuring the texture quality, whereas it is not suitable for papaya fruit because of the abnormal softening and the poor texture

Comparative Analyses of Ripening, Texture Properties and Cell Wall Composition in Three Tropical Fruits Treated with 1-Methylcyclopropene during Cold Storage

Regulation of fruit ripening is one of the most important topics in postharvest storage. Effects of 1-methylcyclopropene (1-MCP) greatly depend on the responsiveness of fruit cultivar to this molecule. Although 1-MCP has been used in postharvest preservation of many fruit species, its effects on ripening process, including ethylene production, and softening of banana, mango, and papaya are still not very clear. In the present study, we comparatively investigated the effects of 1-MCP fumigation treatment (1 &mu;L L&minus;1 for 20 h) on ripening behavior and texture qualities of the three fruits during storage at 15 &deg;C. Results showed that 1-MCP treatment not only suppressed the production but also delayed the peak points of ethylene in banana and mango. However, it only significantly delayed the emergence of peak, but didn&rsquo;t suppress the production of ethylene in papaya. Meanwhile, 1-MCP treated papayas showed the lowest malondialdehyde (MDA) content, cell membrane permeability (CMP) and activities of polygalacturonase (PG) and cellulose (CX), accompanied by the highest firmness and protopectin content. Furthermore, 1-MCP treatment slowed down the changes of pulp cell structure in three kinds of fruit. Thus, the findings suggest that postharvest application of 1-MCP has potential in banana and mango fruits due to both prolonging storage-life and ensuring the texture quality, whereas it is not suitable for papaya fruit because of the abnormal softening and the poor texture

Density Functional Theory Calculations for the Structural, Electronic, and Magnetic Properties of (Gd₂O₃)_<i>n</i>^0,±1 Clusters with <i>n</i> = 1–10

The structural stability and electronic and magnetic properties of stoichiometric (Gd₂O₃)_<i>n</i> clusters with <i>n</i> = 1–10 were investigated using spin-polarized density functional theory through the broken-symmetry approach. Size-induced changes in the point symmetry of these clusters were observed. A large coordination number led to elongation of Gd–O bonding. Either adding an electron to or removing an electron from the ground state of a neutral cluster brought significant changes in the van der Waals volume for clusters <i>n</i> = 1–3. Binding energy increased with cluster size. However, the highest occupied molecular orbital–lowest unoccupied molecular orbital gap, ionization, and electron affinity fluctuated when <i>n</i> increased from 1 to 10. Natural population analysis and partial density of states revealed that the Gd-4f orbital hardly participated in bonding and that the Gd-5d/6s/6p orbitals were hybrid with the O-2p orbitals. The competition between Ruderman–​Kittel–​Kasuya–​Yosida-type and superexchange-type interactions resulted in the magnetic oscillation of clusters between antiferromagnetic and ferromagnetic states. We also found similar behavior in the various structures of Gd₁₂O₁₈. The ground state was easily activated to the excited state because the antiferromagnetic and ferromagnetic coupling states were nearly identical in energy

A Computer-Aided Diagnosis System for Dynamic Contrast-Enhanced MR Images Based on Level Set Segmentation and ReliefF Feature Selection

This study established a fully automated computer-aided diagnosis (CAD) system for the classification of malignant and benign masses via breast magnetic resonance imaging (BMRI). A breast segmentation method consisting of a preprocessing step to identify the air-breast interfacing boundary and curve fitting for chest wall line (CWL) segmentation was included in the proposed CAD system. The Chan-Vese (CV) model level set (LS) segmentation method was adopted to segment breast mass and demonstrated sufficiently good segmentation performance. The support vector machine (SVM) classifier with ReliefF feature selection was used to merge the extracted morphological and texture features into a classification score. The accuracy, sensitivity, and specificity measurements for the leave-half-case-out resampling method were 92.3%, 98.2%, and 76.2%, respectively. For the leave-one-case-out resampling method, the measurements were 90.0%, 98.7%, and 73.8%, respectively