Enhancement of the Structure, Thermal, Linear/Nonlinear Optical Properties, and Antibacterial Activity of Poly (vinyl alcohol)/Chitosan/ZnO Nanocomposites for Eco-Friendly Applications.

The preparation of poly (vinyl alcohol)/chitosan/ZnO (PVA/Cs/ZnO) nanocomposite films as bioactive nanocomposites was implemented through an environmentally friendly approach that included mixing, solution pouring, and solvent evaporation. The nanocomposite films were characterized using various techniques such as X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and UV-Vis spectroscopy. The XRD study revealed the encapsulation of nanoparticles by the PVA/Cs blend matrix. The DSC results showed that the addition of ZnO NPs increased glass transition and melting temperature values of the PVA/Cs blend. ATR-FTIR spectra detected an irregular shift (either red or blue) in some of the characteristic bands of the PVA/Cs nanocomposite, indicating the existence of intra/intermolecular hydrogen bonding creating an interaction between the OH groups of PVA/Cs and ZnO nanoparticles. A thermogravimetric (TGA) analysis demonstrated that the nanocomposites achieved better thermal resistance than a pure PVA/Cs blend and its thermal stability was enhanced with increasing concentration of ZnO nanoparticles. UV analysis showed that with an increase in the content of ZnO NPs, the optical bandgap of PVA/Cs was decreased from 4.43 eV to 3.55 eV and linear and nonlinear parameters were enhanced. Our optical results suggest the use of PVA/Cs/ZnO nanocomposite films for various optoelectronics applications. PVA/Cs/ZnO nanocomposites exhibited significant antibacterial activity against Gram-positive and Gram-negative bacteria. It was found that nanocomposite samples were more effective against Gram-positive compared to Gram-negative bacteria.

Association of TRPV5, CASR, and CALCR genetic variants with kidney stone disease susceptibility in Egyptians through main effects and gene-gene interactions.

Kidney stone disease (KSD) represents an urgent medical problem because of increasing its prevalence. Several functional polymorphisms in genes involved in the renal handling of calcium were associated with KSD pathogenesis. Among those, the rs4236480 of transient receptor potential vanilloid member 5 (TRPV5) gene, the rs1801725 of calcium-sensing receptor (CASR) gene, and the rs1801197 of calcitonin receptor (CALCR) gene appear to be of great importance. Due to the scarce data on the Egyptians, this study aimed to evaluate the association of these candidate genetic variants with the risk of developing KSD in an Egyptian population. To do so, the biochemical parameters were measured along with the genotyping of the three polymorphisms using allelic discrimination assay in 134 KSD patients and 86 age and sex-matched healthy subjects. The results showed that the genotypic distributions and allelic frequencies of the studied variants were significantly different between cases and controls. The three polymorphisms increased the risk of KSD significantly under all the tested genetic models (OR ranges from 2.152 to 5.994), except for the recessive model of the CALCR rs1801197 polymorphism after Bonferroni correction. The gene-gene interaction analyzed by multifactor dimensionality reduction selected the three-locus combination as the best model associated with the susceptibility to KSD with OR 9.706. Further, synergistic interactions were identified between TRPV5 rs4236480 and CALCR rs1801197 variants and CASR rs1801725 and CALCR rs1801197 variants. In conclusion, the TRPV5 rs4236480, CASR rs1801725, and CALCR rs1801197 polymorphisms showed a significant association with the risk of KSD in the Egyptian population. Furthermore, their complex interactions might have an impact on the genetic susceptibility to develop KSD.

Sensitivity and specificity of microRNA-204, CA125, and CA19.9 as biomarkers for diagnosis of ovarian cancer.

BACKGROUND: Ovarian cancer is usually detected at later stages and no effective screening approach, has been identified. Therefore, sensitive and specific biomarkers for detecting ovarian cancer are urgently needed. OBJECTIVE: This study aimed to investigate the efficacy of six biomarkers for the early clinical diagnosis of ovarian cancer. SUBJECTS & METHODS: The study included 120 patients (benign ovarian tumors and early and late ovarian carcinoma) and 30 control healthy volunteers. MiRNA-204, CA125, CA19.9, hepcidin, microfibril-associated glycoprotein 2, and ferroportin levels were determined in all patients and control volunteers. RESULTS: The combined area under the receiver operating characteristic curves for miRNA-204, CA125, and CA19.9 were 0.938, 1.000, and 0.998 for benign tumors and early and late ovarian carcinomas, respectively. The sensitivities of miRNA-204, CA125, and CA19.9 were 98.04%, 100.00%, and 96.19% and the specificities were 58.33%, 62.50%, and 57.78%, respectively. CONCLUSION: The positive predictivity of miRNA-204, CA125, and CA19.9 for ovarian cancer is high (59.57%, 58.24%, and 61.67%, respectively). Thus, the combination of these three biomarkers is a good diagnostic tool for ovarian cancer.

Magnetically Coated Bioabsorbable Stents for Renormalization of Arterial Vessel Walls after Stent Implantation.

The insertion of a stent in diseased arteries is a common endovascular procedure that can be compromised by the development of short- and long-term inflammatory responses leading to restenosis and thrombosis, respectively. While treatment with drugs, either systemic or localized, has decreased the incidence of restenosis and thrombosis these complications persist and are associated with a high mortality in those that present with stent thrombosis. We reasoned that if stents could be made to undergo accelerated endothelialization in the deployed region, then such an approach would further decrease the occurrence of stent thrombosis and restenosis thereby improving clinical outcomes. Toward that objective, the first step necessitated efficient capture of progenitor stem cells, which eventually would become the new endothelium. To achieve this objective, we engineered intrinsic ferromagnetism within nonmagnetizable, biodegradable magnesium (Mg) bare metal stents. Mg stents were coated with biodegradable polylactide (PLA) polymer embedding magnetizable iron-platinum (FePt) alloy nanoparticles, nanomagnetic particles, nMags, which increased the surface area and hence magnetization of the stent. nMags uniformly distributed on stents enabled capture, under flow, up to 50 mL/min, of systemically injected iron-oxide-labeled (IO-labeled) progenitor stem cells. Critical parameters enhancing capture efficiency were optimized, and we demonstrated the generality of the approach by showing that nMag-coated stents can capture different cell types. Our work is a potential paradigm shift in engineering stents because implants are rendered as tissue in the body, and this "natural stealthiness" reduces or eliminates issues associated with pro-inflammatory immune responses postimplantation.

Redox dysregulation, immuno-inflammatory alterations and genetic variants of BDNF and MMP-9 in schizophrenia: Pathophysiological and phenotypic implications.

BACKGROUND: Although a clear mechanism underlying the pathophysiology of schizophrenia (SZ) remains elusive, oxidative stress, inflammatory syndrome and immune activation have become an attractive hypothesis for explaining the pathophysiology of SZ. Data from prior studies on the role of matrix metalloproteinase 9 (MMP-9) and brain-derived neurotrophic factor (BDNF) single nucleotide polymorphisms (SNPs) in SZ are contradictory. We aimed to investigate whether oxidative stress, inflammatory and immune activation markers as well as MMP-9 levels may be implicated in SZ pathogenesis. The association of MMP-9 and BDNF SNPs with the clinical expression of SZ was examined. SUBJECTS AND METHODS: Ninety-four subjects were recruited, including 44 SZ patients and 50 healthy controls. Serum levels of thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), nitrite, C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), Beta-2 microglobulin (Β2M), complement component 3 (C3), C4 and MMP-9 were measured. The MMP-9 -1562C>T and BDNF196G>A SNPs were genotyped using polymerase chain reaction-restriction fragment length polymorphism assay. Psychopathology was assessed using the positive and negative syndrome scale (PANSS). RESULTS: SZ patients showed significantly higher TBARS, PCC, nitrite, CRP, IL-6, TNF-α, Β2M, C3 and MMP-9 levels than controls. In distinguishing SZ patients from healthy controls, CRP and MMP-9 yielded similar discriminatory performance, and both perform better than IL-6, Β2M, C3, nitrite, TBARS, PCC, TNF-α and C4. The MMP-9 -1562C>T SNP genotypes distribution didn't differ significantly between controls and SZ patients. As compared to controls, SZ patients harbor a significantly higher frequency of the BDNF196GG genotype and a lower frequency of the BDNF196GA/AA genotype. Patients carrying the MMP-9 -1562CC or BDNF196GG genotype revealed a significantly higher PANSS than those carrying MMP-9 -1562CT/TT or BDNF196GA/AA genotype. Male gender and the MMP-9 -1562CC genotype were identified as independent predictive factors for higher PANSS. CONCLUSIONS: Redox dysregulation and alterations in the immuno-inflammatory pathways are major culprits in the pathogenesis of SZ. MMP-9 and BDNF SNPs are associated with the clinical phenotype of SZ and, thus, may be a useful marker predicting the phenotypic expression and prognosis of SZ patients.

Presepsin is an early monitoring biomarker for predicting clinical outcome in patients with sepsis.

Despite their undoubted helpfulness in diagnosing sepsis, increased blood C-reactive protein (CRP) and procalcitonin (PCT) levels have been described in many noninfectious conditions. Presepsin is a soluble fragment of the cluster of differentiation 14 involved in pathogen recognition by innate immunity. We aimed to investigate the diagnostic and prognostic performance of presepsin in comparison to PCT and CRP in patients presenting with systemic inflammatory response syndrome (SIRS) and suspected sepsis. Seventy-six subjects were enrolled in this study, including 51 patients with SIRS as well as 25 healthy subjects. Plasma presepsin, PCT and CRP levels were serially measured on admission and at days 1, 3, 7 and 15. Presepsin and PCT yielded similar diagnostic accuracy, whereas presepsin performed significantly better than CRP. Presepsin and PCT showed comparable performance for predicting 28-day mortality, and both biomarkers performed significantly better than CRP. In septic patients, presepsin revealed earlier concentration changes over time when compared to PCT and CRP. Presepsin and PCT could differentiate between septic and non-septic patients with comparable accuracy and both biomarkers showed similar performance for predicting 28-day mortality. Early changes in presepsin concentrations might reflect the appropriateness of the therapeutic modality and could be useful for making effective treatment decisions.

Secreted Phosphoprotein 1 Promoter Genetic Variants Are Associated with the Response to Pegylated Interferon α Plus Ribavirin Combination Therapy in Egyptian Patients with Chronic Hepatitis C Virus Infection.

BACKGROUND/AIMS: The T-helper 1 (TH1) immune reaction is essential for the eradication of hepatitis C virus (HCV) during pegylated interferon α (PEG-IFN-α)- and ribavirin (RBV)-based therapy in chronic HCV patients. Secreted phosphoprotein 1 (SPP1) was shown to be a crucial cytokine for the initiation of a TH1 immune response. We aimed to investigate whether SPP1 single nucleotide polymorphisms (SNPs) may influence sustained virological response (SVR) rates. METHODS: Two SNPs in the promoter region of SPP1 at the -443 C>T and -1748 G>A loci were genotyped in 100 patients with chronic HCV genotype 4 infection using a TaqMan SNP genotyping assay. RESULTS: Sixty-seven patients achieved a SVR, and 33 patients showed no SVR. Patients carrying the T/T genotype at the -443 locus showed a significantly higher SVR rate than those carrying the C/T or C/C genotype (83.67% vs. 50.98%, p<0.001). At the -1748 locus, the SVR rate was significantly higher in patients with the G/G genotype than in those with the A/A genotype (88.89% vs. 52.63%, p=0.028) and in patients with the G/A genotype than in those with the A/A genotype (85.29% vs. 52.63%, p=0.001). CONCLUSIONS: SPP1 SNPs at -443 C>T and -1748 G>A loci may be useful markers for predicting the response to PEG-IFN-α-2b plus RBV therapy in Egyptian patients with chronic HCV genotype 4 infection.

Secreted Phosphoprotein 1 Promoter Genetic Variants Are Associated with the Response to Pegylated Interferon alpha Plus Ribavirin Combination Therapy in Egyptian Patients with Chronic Hepatitis C Virus Infection

BACKGROUND/AIMS: The T-helper 1 (TH1) immune reaction is essential for the eradication of hepatitis C virus (HCV) during pegylated interferon alpha (PEG-IFN-alpha)- and ribavirin (RBV)-based therapy in chronic HCV patients. Secreted phosphoprotein 1 (SPP1) was shown to be a crucial cytokine for the initiation of a TH1 immune response. We aimed to investigate whether SPP1 single nucleotide polymorphisms (SNPs) may influence sustained virological response (SVR) rates. METHODS: Two SNPs in the promoter region of SPP1 at the -443 C>T and -1748 G>A loci were genotyped in 100 patients with chronic HCV genotype 4 infection using a TaqMan SNP genotyping assay. RESULTS: Sixty-seven patients achieved a SVR, and 33 patients showed no SVR. Patients carrying the T/T genotype at the -443 locus showed a significantly higher SVR rate than those carrying the C/T or C/C genotype (83.67% vs 50.98%, pT and -1748 G>A loci may be useful markers for predicting the response to PEG-IFN-alpha-2b plus RBV therapy in Egyptian patients with chronic HCV genotype 4 infection.

Diffusive transfer between two intensely interacting cells with limited surface kinetics.

The diffusive transfer, or paracrine delivery, of chemical factors during the interaction of an emitting cell and a receiving cell is a ubiquitous cellular process that facilitates information exchange between the cells an/or to bystander cells. In the cellular immune response this exchange governs the magnitude and breadth of killing of cellular targets, inflammation or tolerance. Paracrine delivery is examined here by solving the the steady-state diffusion equation for the concentration field surrounding two intensely interacting, equi-sized cells on which surface kinetics limits the rates of factor emission and absorption. These chemical factors may be cytokines, such as Interlukins and Interferons, but the results are presented in a generic form so as to be applicable to any chemical factor and/or cell-type interaction. In addition to providing overall transfer rates and transfer efficiencies, the results also indicate that when the receiving cell is naïve, with few factor receptors on its surface, there may be a significant accumulation of factor in the synaptic region between the cells with a consequent release of factor to the medium where it can signal bystander cells. This factor accumulation may play a critical role in activating a naïve receiving cell. As the receiving cell activates and becomes more absorbent, the factor accumulation diminishes, as does potential bystander signaling.

Nanoparticle delivery of mycophenolic acid upregulates PD-L1 on dendritic cells to prolong murine allograft survival.

Conventional immunosuppressive drug delivery requires high systemic drug levels to provide therapeutic benefit, but frequently results in toxic side effects. Novel drug delivery methods, such as FDA-approved poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), are promising drug delivery platforms to reduce drug doses and minimize toxicity. Using murine models of skin transplantation, we investigated whether PLGA NPs would effectively deliver mycophenolic acid (MPA), a common clinical immunosuppressant, and avoid the toxicity of conventional drug delivery. We found that intermittent treatment with NPs encapsulated with MPA (NP-MPA) resulted in a significant extension of allograft survival than intermittent conventional MPA treatment even though the concentration of MPA within NP-MPA was a 1000-fold lower than conventional drug. Importantly, recipients who were administered NP-MPA intermittently avoided drug toxicity, whereas those treated with daily conventional drug manifested cytopenias. Dendritic cells (DCs) endocytosed NP-MPA to upregulate programmed death ligand-1 (PD-L1) and displayed a decreased ability to prime alloreactive T cells. Importantly, the ability of NP-MPA to promote allograft survival was partly PD-L1 dependent. Collectively, this study indicates that NPs are potent drug delivery tools that extend allograft survival without drug toxicity.

Initial evaluation of the use of USPIO cell labeling and noninvasive MR monitoring of human tissue-engineered vascular grafts in vivo.

This pilot study examines noninvasive MR monitoring of tissue-engineered vascular grafts (TEVGs) in vivo using cells labeled with iron oxide nanoparticles. Human aortic smooth muscle cells (hASMCs) were labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. The labeled hASMCs, along with human aortic endothelial cells, were incorporated into eight TEVGs and were then surgically implanted as aortic interposition grafts in a C.B-17 SCID/bg mouse host. USPIO-labeled hASMCs persisted in the grafts throughout a 3 wk observation period and allowed noninvasive MR imaging of the human TEVGs for real-time, serial monitoring of hASMC retention. This study demonstrates the feasibility of applying noninvasive imaging techniques for evaluation of in vivo TEVG performance.

Increased TCR avidity after T cell activation: a mechanism for sensing low-density antigen.

While activated T cells are known to have enhanced biological responses to antigen stimulation, the biophysical basis of this increased sensitivity remains unknown. Here, we show that, on activated T cells, the TCR avidity for peptide-MHC complexes is 20- to 50-fold higher than the TCR avidity of naive T cells. This increased avidity for peptide-MHC depends on TCR reorganization and is sensitive to the cholesterol content of the T cell membrane. Analysis of the binding data indicates the enhanced avidity is due to increases in cross-linking of TCR on activated T cells. Activation-induced membrane (AIM) changes in TCR avidity represent a previously unrecognized means of increasing the sensitivity of activated T cells to small amounts of antigen in the periphery.

Enhanced antigen-specific antitumor immunity with altered peptide ligands that stabilize the MHC-peptide-TCR complex.

T cell responsiveness to an epitope is affected both by its affinity for the presenting MHC molecule and the affinity of the MHC-peptide complex for TCR. One limitation of cancer immunotherapy is that natural tumor antigens elicit relatively weak T cell responses, in part because high-affinity T cells are rendered tolerant to these antigens. We report here that amino acid substitutions in a natural MHC class I-restricted tumor antigen that increase the stability of the MHC-peptide-TCR complex are significantly more potent as tumor vaccines. The improved immunity results from enhanced in vivo expansion of T cells specific for the natural tumor epitope. These results indicate peptides that stabilize the MHC-peptide-TCR complex may provide superior antitumor immunity through enhanced stimulation of specific T cells.

Soluble, high-affinity dimers of T-cell receptors and class II major histocompatibility complexes: biochemical probes for analysis and modulation of immune responses.

T cell receptors (TCR) and major histocompatibility complex (MHC) molecules are integral membrane proteins that have central roles in cell-mediated immune recognition. Therefore, soluble analogs of these molecules would be useful for analyzing and possibly modulating antigen-specific immune responses. However, due to the intrinsic low-affinity and inherent solubility problems, it has been difficult to produce soluble high-affinity analogs of TCR and class II MHC molecules. This report describes a general approach which solves this intrinsic low-affinity by constructing soluble divalent analogs using IgG as a molecular scaffold. The divalent nature of the complexes increases the avidity of the chimeric molecules for cognate ligands. The generality of this approach was studied by making soluble divalent analogs of two different classes of proteins, a TCR (2C TCR2Ig) and a class II MHC (MCCI-Ek2Ig) molecule. Direct flow cytometry assays demonstrate that the divalent 2C TCR2Ig chimera retained the specificity of the native 2C TCR, while displaying increased avidity for cognate peptide/MHC ligands, resulting in a high-affinity probe capable of detecting interactions that heretofore have only been detected using surface plasmon resonance. TCR2IgG was also used in immunofluorescence studies to show ER localization of intracellular peptide-MHC complexes after peptide feeding. MCCI-Ek2Ig chimeras were able to both stain and activate an MCC-specific T cell hybridoma. Construction and expression of these two diverse heterodimers demonstrate the generality of this approach. Furthermore, the increased avidity of these soluble divalent proteins makes these chimeric molecules potentially useful in clinical settings for probing and modulating in vivo cellular responses.

Effects of extraction of ubiquinone on succinate-ferricyanide reductase activity.

The effects of extraction and reincorporation of ubiquinone on succinate dehydrogenase of mitochondrial membranes have been studied. The succinate dehydrogenase activity, measured with ferricyanide as electron acceptor, was diminished by approximatively 75% upon the extraction of ubiquinone and was restored when ubiquinone was reincorporated into the membranes. A study in a model system represented by ubiquinols incorporated in liposomes shows that the initial rates of ubiquinol oxidation by external ferricyanide are almost two order of magnitude lower than the rates of succinate-ferricyanide reductase in mitochondria. It is therefore concluded that the compound feeding electrons to ferricyanide in damaged mitochondria is either ubiquinone in a bound form or a compound between UQ and the antimycin block.