Cytokine single nucleotide polymorphisms in Iranian patients with pulmonary tuberculosis

BACKGROUND: Several genes coding for different cytokines may affect host susceptibility to tuberculosis. METHODS: In the present study, the allele and genotype frequencies of a number polymorphic genes coding for cytokines or cytokine receptors were investigated in Iranian patients with pulmonary tuberculosis (PTB). RESULTS: From the IL-1 cluster, a positive, significant difference was found at position -889, where the T/T genotype was over represented in PTB patients (p = 0.01); a positive, significant increase was found in the IL1R PstI 1970 C/C genotype, where the C allele was over represented in the PTB patients (p = 0.01). A significant negative association at codon 10 TGF-beta, T allele, was shown in our patients and the C allele and C/C genotype were over represented in the PTB patients (P<0.005). For TNF-alpha at position -238, we found a negative association for the G/A genotype and a positive association for the G/G genotype (p = 0.0009). Significant negative associations at position -590 IL-4, T allele and the T/T genotype were shown in our patients (p = 0.0007); also, the C allele and T/C genotype were significantly increased in our patients (P<0.05). With IL-6 at -174, G/G increased and G/C decreased significantly in the patients (P<0.005). CONCLUSION: Pro-inflammatory cytokines such as TNF-alpha and TGF-beta seem to be decreased, and IL-6 increased in PTB patients.     

Vulture Genomes Reveal Molecular Adaptations Underlying Obligate Scavenging and Low Levels of Genetic Diversity

Obligate scavenging on the dead and decaying animal matter is a rare dietary specialization that in extant vertebrates is restricted to vultures. These birds perform essential ecological services, yet many vulture species have undergone recent steep population declines and are now endangered. To test for molecular adaptations underlying obligate scavenging in vultures, and to assess whether genomic features might have contributed to their population declines, we generated high-quality genomes of the Himalayan and bearded vultures, representing both independent origins of scavenging within the Accipitridae, alongside a sister taxon, the upland buzzard. By comparing our data to published sequences from other birds, we show that the evolution of obligate scavenging in vultures has been accompanied by widespread positive selection acting on genes underlying gastric acid production, and immunity. Moreover, we find evidence of parallel molecular evolution, with amino acid replacements shared among divergent lineages of these scavengers. Our genome-wide screens also reveal that both the Himalayan and bearded vultures exhibit low levels of genetic diversity, equating to around a half of the mean genetic diversity of other bird genomes examined. However, demographic reconstructions indicate that population declines began at around the Last Glacial Maximum, predating the well-documented dramatic declines of the past three decades. Taken together, our genomic analyses imply that vultures harbor unique adaptations for processing carrion, but that modern populations are genetically depauperate and thus especially vulnerable to further genetic erosion through anthropogenic activities.     

Cytokine response following transthoracic and transhiatal esophagectomy in patients with esophageal cancer

Curative esophageal resection is usually performed using either a transthoracic (TT) or transhiatal (TH) approach. Forty patients with esophageal squamous cell carcinoma who underwent esophagectomies (24 TT and 16 TH), 12 patients who underwent surgery for gastric cancer, and 16 healthy individuals were enrolled in this study. Blood samples were taken from the patients, pre- and post-surgery. The levels of synthesis of T-helper 1 and 2 cytokines were assessed in vitro in the presence of mitogen. Our initial data indicated that at admission, 24 h before surgery, blood cells from both groups of esophageal cancer patients produced significantly lower levels of the Th1 cytokines, IFN-gamma and IL-2 than those from cells of healthy donors. Cells collected from gastric cancer patients prior to surgery produced intermediate levels of IFN-gamma and IL-2: significantly lower than healthy donors, and slightly more (non-significant) than esophageal cancer patients. These results contrast with those for the production of Th2 cytokines prior to surgery, which did not differ significantly between any groups: either the esophageal or gastric cancer patients, or healthy donors. Th1 and Th2 cytokine production was then studied using blood cells collected seven days after surgery. Cells from both groups of esophageal cancer patients, undergoing either TT or TH surgery, produced significantly lower levels of the Th1 cytokines, IFN-gamma and IL-2 than those from cells of gastric cancer patients who had undergone surgery. Postoperative and preoperative production was compared. For patients who had undergone TT esophageal resection, we observed that the post-operative production of IL-2, IL-5 and IL-13 was significantly lower than the pre-operative production of those cytokines. Such reduced post-operative compared to pre-operative production was only significant in patients who had undergone TT esophagectomy. A similar, but non-significant trend was observed in patients who had undergone either TH esophagectomy, or gastrectomy. The results indicate that digestive tract cancer patients, both esophageal and gastric, have (prior to surgery), a significantly reduced, basal, mitogen-induced production of Th1 but not of Th2 cytokine. Post-operatively, a significantly reduced production of Th1 and Th2 cytokines, except for IFN-gamma, was observed only in patients who had undergone surgical esophageal resection using the TT method.     

The effect of temperature on antibacterial activity of biosynthesized silver nanoparticles

The purpose of this study was the evaluation of two different temperatures on antibacterial activity of the biosynthesized silver nanoparticles. 38 silver nanoparticles-producing bacteria were isolated from soil and identified. Biosynthesis of silver nanoparticles by these bacteria was verified through visible light spectrophotometry. Two strains were relatively active for production of silver nanoparticles. These strains were subjected for molecular identification and recognized as Bacillus sp. and Acinetobacter schindleri. In the present study, the effect of temperatures was evaluated on structure and antimicrobial properties of the silver nanoparrticles by transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis and antimicrobial Agar well diffusion methods. The silver nanoparticles showed antibacterial activity against all the pathogenic bacteria; however, this property was lost after treatment of the silver nanoparticles by high temperatures (100 and 300 °C). TEM images showed that the average sizes of heated silver nanoparticles were >100 nm. However, these were <100 nm for non-heated silver nanoparticles. Although, XRD patterns showed the crystalline structure of heated silver nanoparticles, their antibacterial activities were less. This was possible because of the sizes and accordingly less penetration of the particles into the bacterial cells. In addition, elimination of the capping agents by heat might be considered another reason.     

Strategies for optimizing DNA hybridization on surfaces

Specific and predictable hybridization of the polynucleotide sequences to their complementary counterparts plays a fundamental role in the rational design of new nucleic acid nanodevices. Generally, nucleic acid hybridization can be performed using two major strategies, namely hybridization of DNA or RNA targets to surface-tethered oligonucleotide probes (solid-phase hybridization) and hybridization of the target nucleic acids to randomly distributed probes in solution (solution-phase hybridization). Investigations into thermodynamic and kinetic parameters of these two strategies showed that hybridization on surfaces is less favorable than that of the same sequence in solution. Indeed, the efficiency of DNA hybridization on surfaces suffers from three constraints: (1) electrostatic repulsion between DNA strands on the surface, (2) steric hindrance between tethered DNA probes, and (3) nonspecific adsorption of the attached oligonucleotides to the solid surface. During recent years, several strategies have been developed to overcome the problems associated with DNA hybridization on surfaces. Optimizing the probe surface density, application of a linker between the solid surface and the DNA-recognizing sequence, optimizing the pH of DNA hybridization solutions, application of thiol reagents, and incorporation of a polyadenine block into the terminal end of the recognizing sequence are among the most important strategies for enhancing DNA hybridization on surfaces.     

Clustered epitopes within a new poly-epitopic HIV-1 DNA vaccine shows immunogenicity in BALB/c mice

Despite a huge number of studies towards vaccine development against human immunodeficiency virus-1, no effective vaccine has been approved yet. Thus, new vaccines should be provided with new formulations. Herein, a new DNA vaccine candidate encoding conserved and immunogenic epitopes from HIV-1 antigens of tat, pol, gag and env is designed and constructed. After bioinformatics analyses to find the best epitopes and their tandem, nucleotide sequence corresponding to the designed multiepitope was synthesized and cloned into pcDNA3.1+ vector. Expression of pcDNA3.1-tat/pol/gag/env plasmid was evaluated in HEK293T cells by RT-PCR and western-blotting. Seven groups of BALB/c mice were intramuscularly immunized three times either with 50, 100, 200 µg of plasmid in 2-week intervals or with similar doses of insert-free plasmid. Two weeks after the last injection, proliferation of T cells and secretion of IL4 and IFN-γ cytokines were evaluated using Brdu and ELISA methods, respectively. Results showed the proper expression of the plasmid in protein and mRNA levels. Moreover, the designed multiepitope plasmid was capable of induction of both proliferation responses as well as IFN-γ and IL-4 cytokine production in a considerable level compared to the control groups. Overall, our primary data warranted further detailed studies on the potency of this vaccine.     

Plasma PCSK9 Levels Are Elevated with Acute Myocardial Infarction in Two Independent Retrospective Angiographic Studies

Objective

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a circulating protein that promotes degradation of the low density lipoprotein (LDL) receptor. Mutations that block PCSK9 secretion reduce LDL-cholesterol and the incidence of myocardial infarction (MI). However, it remains unclear whether elevated plasma PCSK9 associates with coronary atherosclerosis (CAD) or more directly with rupture of the plaque causing MI.

Methods and Results

Plasma PCSK9 was measured by ELISA in 645 angiographically defined controls (<30% coronary stenosis) and 3,273 cases of CAD (>50% stenosis in a major coronary artery) from the Ottawa Heart Genomics Study. Because lipid lowering medications elevated plasma PCSK9, confounding association with disease, only individuals not taking a lipid lowering medication were considered (279 controls and 492 with CAD). Replication was sought in 357 controls and 465 with CAD from the Emory Cardiology Biobank study. PCSK9 levels were not associated with CAD in Ottawa, but were elevated with CAD in Emory. Plasma PCSK9 levels were elevated in 45 cases with acute MI (363.5±140.0 ng/ml) compared to 398 CAD cases without MI (302.0±91.3 ng/ml, p = 0.004) in Ottawa. This finding was replicated in the Emory study in 74 cases of acute MI (445.0±171.7 ng/ml) compared to 273 CAD cases without MI (369.9±139.1 ng/ml, p = 3.7×10⁻⁴). Since PCSK9 levels were similar in CAD patients with or without a prior (non-acute) MI, our finding suggests that plasma PCSK9 is elevated either immediately prior to or at the time of MI.

Conclusion

Plasma PCSK9 levels are increased with acute MI.