Profile of Hepatitis B Virus Mutations Associated with HBsAg-Negative Disease in Patients of Hemodialysis Centers

The aim of this study was to characterize mutations in the hepatitis B virus (HBV) genome associated with HBsAg-negative form of the disease in patients receiving hemodialysis replacement therapy. Materials and methods. We used blood plasma samples obtained from hemodialysis centers in St. Petersburg, Russia – 173 patients and 108 patients from Belgrade, Republic of Serbia. The samples were examined for the presence of serological (HBsAg, antibodies anti-HBs IgG, anti-HBcore IgG) and molecular-genetic (HBV DNA) markers of HBV followed by whole-genome sequencing and determination of clinically significant virus mutations. Results and discussion. Antibodies to hepatitis B were detected in 7.5 % and 11.1 % of patients from St. Petersburg and Belgrade, respectively. HBsAg was identified only in 1.1 % of cases in the group from Russia and in 0.9 % of cases in the group from Serbia. HBV DNA was determined in 2.8 % of the studied samples from both, patients from Saint-Petersburg and Belgrade. Phylogenetic analysis of 9 viral isolates showed that genotype D virus (88.9 %) prevailed as compared to genotype A (11.1 %) in the examined group. Among the samples obtained from patients from St. Petersburg, four belonged to the D2 sub-genotype, one to the D3 genotype. Four samples obtained from Belgrade patients belonged to different sub-genotypes – D1, D2, D3, A2, respectively. When analyzing the nucleotide sequences of the HBV genomes, mutations in the MHR region were detected in all cases, but only in HBsAg-negative isolates, mutations were revealed in the region of 124–147 amino acids, including mutations P120T, R122K, A128V, Q129R, M133I, G145R affecting the recognition of HBsAg by anti-HBs antibodies and associated with the resistance of the virus to the vaccine. The results of this study indicate that transmission of blood-borne viral hepatitis agent in the hemodialysis departments of the Russian Federation and the Republic of Serbia still exists. The prevalence of the latent chronic hepatitis B, coupled with the presence of vaccine escape mutations in all identified cases, indicates the need to pay close attention to the occurrence of the virus mutant variants in hemodialysis centers

Very slow surface plasmons: theory and practice

The paper is of a methodological character and has as a goal to give a brief description of the concept of theory and practical application of very slow optical plasmons. They exist on the metal-dielectric boundaries, namely, on very thin metal films and fibers and as standing waves on metal spheres and ellipsoids. The material presented in the paper features by widening the common concepts of electromagnetic modes of various spaces, of the probability of spontaneous emission, of creation of optical images, of the limits of optical focusing, and of the photon linear momentum. All mentioned studies are completed in recent years. The problem of the photon momentum in a dielectric medium was the topic of irreconcilable disputes for 100 years starting in the time of appearing of Minkowski and Abraham famous papers. Various practical applications are surveyed: the experiments with a great intensification of an atom spontaneous emission into a plasmonic field mode of a metal nanoparticle, the experiments on focusing optical radiation into a spot that substantially smaller than a diffraction limited spot, a so called near perfect Pendry lens that produces the image with details that substantially smaller than defined by diffraction, and lastly, the concept of hundredfold and more magnification of a photon mechanical linear momentum in a plasmon. The work completed is supported by RFBR, grants Nos 05-02-19647, 07-02-01328.Comment: 19 pages, 13 figure