[Identification by enzyme immunoassay of escape mutants S143L and G145R of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus)].

INTRODUCTION: The achievement of the goal of the World Health Organization to eliminate viral hepatitis B by 2030 seems to be problematic partly due to the presence of escape mutants of its etiological agent, hepatitis B virus (HBV) (<i>Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus</i>), that are spreading mainly in the risk groups. Specific routine diagnostic assays aimed at identification of HBV escape mutants do not exist.The study aimed the evaluation of the serological fingerprinting method adapted for routine detection of escape mutations in 143 and 145 aa positions of HBV surface antigen (HBsAg). MATERIAL AND METHODS: HBV DNA from 56 samples of HBsAg-positive blood sera obtained from donors, chronic HBsAg carriers and oncohematology patients has been sequenced. After the identification of mutations in HBsAg, the samples were tested in the enzyme-linked immunosorbent assay (ELISA) kit «Hepastrip-mutant-3K¼. RESULTS AND DISCUSSION: Escape mutations were detected mainly in patients with hematologic malignancies. Substitutions in 143 and 145 aa were found in 10.81% and in 8.11% of such patients, respectively. The G145R mutation was recognized using ELISA kit in almost all cases. The kit specifically recognized the S143L substitution in contrast to the S143T variant. The presence of neighbor mutation D144E can be assumed due to it special serological fingerprint. CONCLUSION: ELISA-based detection of escape mutations S143L, D144E and G145R can be used for routine diagnostics, especially in the risk groups. The diagnostic parameters of the kit can be refined in additional studies. This immunoassay and methodology are applicable for the development and quality control of vaccines against escape mutants.

[Search for RNA of the hepatitis E virus autochthonous for Russia in the most likely infection sources].

The research carried out for 30 years from the moment of hepatitis E virus (HEV) discovery has proved the presence of the autochthonous HEV in non-endemic areas: Europe and Russia. Monitoring of the HEV antibodies (anti-HEV) among the Russian population has revealed regions with increased seroprevalence that testifies to high probability of local HEV infection in these areas. Contact with HEV can represent special danger for patients of the risk groups. In this work, the blood sera testing was carried out in order to assess the anti-HEV presence among these contingents (groups). Seropositive sera from the patients from the regions with high anti-HEV seroprevalence, risk groups patients, samples with high probability of HEV occurrence including the animals as possible reservoir, have been used for RNA extraction. The developed system of HEV RNA detection both in real-time RT-PCR and in a nested PCR variant has confirmed its sensitivity to the synthetic reference templates and positive control samples in commercial test system (Genesig, Great Britain). HEV RNA was absent in all tested samples. This indicates a low frequency of the autochthonous HEV carriage occurrence. Sampling enlargement to tens of thousands persons is necessary for significant HEV RNA detection.

Magnetic resonance imaging-guided renal artery stent placement in a Swine model: comparison of two tracking techniques.

BACKGROUND: Magnetic resonance (MR)-guided interventions have evolved from a pure research application to a preclinical method over the last decade. Among the device-tracking techniques, susceptibility artifact-based tracking relies on the contrast between the surrounding blood and the device, and radiofrequency coil-based tracking relies on the local gradient field amplification in a resonating circuit attached to the interventional device. PURPOSE: To evaluate the feasibility and precision of susceptibility artifact-based and microcoil-based MR guidance methods for renal artery stent placement in a swine model. MATERIAL AND METHODS: MR imaging-guided renal artery stent placements were performed in six fully anesthetized pigs using a 1.5T short-bore MR scanner. Susceptibility artifact-based tracking with manual scan-plane adjustments and microcoil tracking with automatic scan-plane adjustments were used for renal artery stent placements in three pigs in each group. With both methods, near real-time steady-state free-precession (SSFP) imaging was used. Differences between the two tracking approaches on stenting time, total procedure time, and stent position were measured. RESULTS: The microcoil-based approach yielded a shorter mean procedure time (17 vs. 23 min). There was no relevant difference for the mean stenting time (12 vs. 13 min). The mean stent deviation from the aortic wall with the susceptibility approach was larger than with the microcoil approach (10 vs. 4.0 mm). CONCLUSION: For MRI-guided renal artery stent placement, the microcoil-based technique had a shorter procedure time and a higher stent placement precision than the susceptibility artifact-based approach.

A method for fast 3D tracking using tuned fiducial markers and a limited projection reconstruction FISP (LPR-FISP) sequence.

This work demonstrates the feasibility of using wireless, tuned fiducial markers with a limited projection reconstruction-fast imaging with steady-state free precession sequence (LPR-FISP) to accurately obtain tracking information necessary for interactive scan plane selection in magnetic resonance imaging (MRI). The position and orientation of a rigid interventional device can be uniquely determined from the 3D coordinates of three fiducial markers mounted in a known configuration on the device. Three fiducial markers were tuned to the proton resonant frequency in a 0.2T open MR scanner and mounted to the surface of a cylindrical water phantom. An LPR-FISP sequence was developed to suppress the water phantom signal while preserving that of the fiducial markers through a nonselective low-tip-angle excitation and a dephaser gradient applied prior to data acquisition. A localization algorithm was developed to accurately calculate the 3D coordinates of the fiducial markers using four LPR-FISP projections in two orthogonal scan planes. The sequence repetition time (TR = 21 msec) and the limited projection set resulted in fast LPR-FISP coordinate acquisition times of approximately 170 msec with an accuracy (max error) of 3 mm on a 0.2T MR system. This fast, accurate tracking method provides the fundamental technology for interactive MRI scan plane definition for rigid interventional devices without the need for stereotactic cameras or reference frames.