Search Results (112)

The aim of the study was to assess the seroprevalence of hantaviruses, the causative agents of hemorrhagic fever with renal syndrome (HFRS), and their distribution to socio-demographic characteristics among the populations of Saint Petersburg and the Leningrad Region. A total of 4464 samples were analyzed, including 2265 samples from residents of Saint Petersburg and 2199 samples from residents of the Leningrad Region. Blood plasma samples were tested for specific immunoglobulin G (IgG) antibodies using enzyme-linked immunosorbent assay (ELISA). Blood samples were collected in 2023 from randomly selected volunteers. Hantavirus seroprevalence in Saint Petersburg was 5.39%, while in the Leningrad Region, it was 8.55%. In both regions, the highest proportion of seropositive individuals was found among volunteers aged ≥70 years, whereas the lowest seroprevalence was observed in the 1–17-year age group (inclusive). Seroprevalence was significantly higher in men than in women in both regions. The seroprevalence values identified in this study are comparable to those reported in similar studies in areas with a high incidence of HFRS. These findings may indicate that the true incidence of HFRS may be significantly higher than officially registered in Saint Petersburg and the Leningrad Region. Full article

The extraordinary genetic diversity of human immunodeficiency virus type 1 (HIV-1), driven by high mutation and recombination rates, poses significant challenges for diagnostics, therapy, and vaccine development. While variable regions enable immune escape, hyperconserved regions are critical for viral function and represent promising targets for novel therapeutic interventions. This study aimed to develop and validate a bioinformatic algorithm for quantitative assessment of sequence conservation and automated identification of functionally significant conserved regions across all major HIV-1 proteins. A total of 1119 full-length HIV-1 genome sequences representing major subtypes (A1, A2, A6, B, C, D, F1, F2, G, H, J, K) were analyzed. Normalized Shannon entropy (S-index) was calculated for each alignment column. Statistical thresholds for conserved regions were established using 95% confidence intervals derived from bootstrap resampling. Two complementary algorithms, clustering and local maxima detection, were applied to identify conserved regions, which were subsequently mapped to known functional domains based on literature data. Protein conservation varied markedly, with S_m values ranging from 0.784 (Vpu) to 0.920 (Pol). Gag, Pol, and Vpr demonstrated the highest overall conservation, while Env, Rev, Tat, and Vpu exhibited pronounced variability interspersed with conserved domains. In total, 25 conserved regions in Gag, 49 in Pol, 28 in Env, and 6–4 regions in accessory proteins (Vif, Vpr, Rev, Tat, Nef, Vpu) were identified. These regions corresponded to critical functional elements including enzyme catalytic centers, zinc fingers, receptor-binding sites, protein interaction interfaces, and membrane-anchoring domains. The developed computational framework enables statistically grounded identification of evolutionarily constrained regions across analyzed HIV-1 subtypes. The identified conserved regions represent candidate sites for further investigation and may inform downstream studies focused on antiviral target prioritization, immunogen design, and diagnostic assay development. However, their translational applicability requires additional analytical, structural, and experimental validation. Full article

The hepatitis B (HBV), C (HCV), and D (HDV) viruses remain a major public health burden. Occult HBV infection (OBI) represents a hidden reservoir with clinical and epidemiological significance, yet its prevalence in Northwest Russia is unknown. We aimed to comprehensively assess the serological and molecular epidemiology of HBV, HCV, and HDV in St. Petersburg and the Leningrad region. Methods. In this cross-sectional study, 6773 apparently healthy volunteers were enrolled. Plasma samples were tested for hepatitis B surface antigen (HBsAg), antibodies to HBV core antigen (anti-HBc), antibodies to HBsAg (anti-HBs), antibodies to HCV (anti-HCV), and antibodies to HDV (anti-HDV) by ELISA. All anti-HCV- and anti-HDV-positive samples were tested for HCV RNA and HDV RNA by real-time PCR. All samples were tested for HBV DNA using a highly sensitive in-house nested real-time PCR assay (detection limit: 5 IU/mL). All “HBV DNA-positive, HBsAg-negative” cases confirmed by two independent extractions were classified as OBI. Vaccination status, self-reported history, and iatrogenic interventions were recorded. Results. Overall seroprevalence values were: HBsAg 1.7%; anti-HBc 11.3%; anti-HBs 43.0%; anti-HCV 1.9%; and anti-HDV 0.6%. Anti-HBc increased sharply with age (3.1% in children to 26.4% in the elderly, p < 0.0001), while anti-HBs declined (69.9% to 29.8%, p < 0.0001). HBV DNA was detected in 118 participants (1.7%). Of these, only 73 individuals (1.1%) were HBsAg-positive, while the remaining 45 participants (0.7%) had undetectable HBsAg, meeting the criteria for OBI. OBI was detected across all age groups, including children. Serological profiling of OBI cases revealed that 57.8% lacked both anti-HBc and anti-HBs, 35.6% had isolated anti-HBs, 2.2% had isolated anti-HBc, and 4.4% had both antibodies. HCV RNA was detected in 15.0% of anti-HCV-positive individuals (all adults). No HDV RNA was detected. Self-reported history underestimated true infection rates: 1.4% of those denying HBV infection were HBsAg-positive and 10.6% were anti-HBc-positive. Among those denying HCV infection, 1.4% were anti-HCV-positive. Vaccination coverage was 70.8%, declining from 90.9% in children to 39.0% in the elderly (p < 0.0001). Among vaccinated individuals, 48.0% lacked protective anti-HBs (<10.0 mIU/mL). Conclusions. This comprehensive serological and molecular study in Northwest Russia is the first to combine population-level serology with molecular detection of HBV, HCV, and HDV, including OBI in this region, and reveals that OBI accounts for a substantial proportion (38%) of all active HBV infections and is strongly associated with a history of iatrogenic interventions. The presence of OBI across all age groups, including children, shows that HBsAg screening alone substantially underestimates the true HBV burden. High rates of unrecognized infection and waning vaccine-induced immunity, highlight critical gaps in current surveillance. These findings provide an evidence-based rationale for integrating molecular testing into screening algorithms and for considering booster vaccination strategies to achieve viral hepatitis elimination goals. Full article

Background: Hepatitis A (HA) and E (HE) represent a significant global health burden. Despite the development of effective vaccines against hepatitis A virus (HAV) and hepatitis E virus (HEV), outbreaks of acute HA and HE continue to occur worldwide. This study aimed to assess the seroprevalence of anti-HAV and anti-HEV IgG antibodies (Abs) in the population of Belgrade and to analyze their association with socio-demographic and clinical factors. Materials and Methods: A cross-sectional study was conducted on a sample of 2533 healthy volunteers in Serbia in May 2024. Participation was voluntary and web-based, leading to an overrepresentation of women and middle-aged adults, while children were underrepresented. Due to this non-probabilistic recruitment, the absolute seroprevalence estimates have limited generalizability to the entire population of Belgrade. Serum samples were tested for anti-HAV and anti-HEV IgG using commercial ELISA kits. The anti-HEV estimate is based on a single ELISA without confirmatory testing and should be interpreted with this limitation in mind. Statistical analysis included confidence interval estimation, chi-square tests, and Spearman’s correlation. Results: Overall seroprevalence was 20.5% (95% CI: 18.9–22.1) for anti-HAV and 22.6% (95% CI: 21.0–24.3) for anti-HEV. A strong, non-linear increase in anti-HAV seroprevalence with age was observed, rising sharply from 2.8% in the 18–29 group to 78.3% in those aged 70+. Anti-HEV seroprevalence also featured a significant positive correlation with age (rs = 0.99, p < 0.0001), increasing from 4.2% in children (1–17 years) to 49.2% in the 70+ group. Men had significantly higher anti-HAV seroprevalence than women (23.1% vs. 19.3%, p = 0.029). Individuals with a history of surgical interventions or blood transfusions had significantly higher odds of being anti-HEV positive (OR = 1.41, p = 0.0005). Vaccination coverage against HAV was low (1.8%), and Abs were detected in only 28.6% of vaccinated individuals. Conclusions: This study suggests high HEV seroprevalence and an age-polarized HAV seroprevalence in Serbia, indicating a significant shift in the epidemiological landscape while acknowledging the sampling and assay limitations stated above. The findings underscore a growing population susceptible to HAV and highlight the need for reinforced vaccination strategies, improved diagnostics, and targeted public health interventions. Full article

ESKAPE pathogens represent a critical threat to global health. This challenge necessitates the development of novel antibacterial strategies. We investigated the antimicrobial potential of NK-92 cells and their derived large extracellular vesicles using flow cytometry, ELISA, confocal microscopy and microbiology assays. Here, we show that both NK-92 cells and NK-92-derived LEVs can interact with bacteria, as confirmed by confocal microscopy and flow cytometry. This interaction is associated with inhibition of colony formation. A possible mechanism can involve defensin-α1 secreted by NK-92 and packed in their LEVs. NK-92-derived LEVs can modulate S. aureus viability, colony growth and clindamycin susceptibility. These findings suggest NK cell-derived LEVs as promising strategies to combat multidrug-resistant bacterial infections. Full article

The secretome of ESKAPE pathogens, including Klebsiella pneumoniae, comprises a diverse array of bioactive molecules that govern virulence, antibiotic resistance, and the establishment of an immunosuppressive microenvironment. However, the high chemical complexity of the secretome impedes the identification of key metabolites mediating pathogenesis. In this study, we profiled the metabolite composition of cell-free K. pneumoniae supernatant using a combined approach of chromatographic fractionation and Raman spectroscopy. Chromatographic separation enabled the resolution of the complex secretome and revealed fractions with distinct biochemical signatures. A key finding was the identification of Fraction 3, characterized by a unique metabolic profile: it was enriched in nucleic acid fragments, peptides containing tyrosine and methionine, polysaccharides, and stress-response metabolites (e.g., citrate), while notably lacking markers of tryptophan and sterol-like lipids. These spectral signatures suggest a potential role for Fraction 3 metabolites in intercellular communication, biofilm formation, and protection against oxidative stress. The remaining fractions also exhibited distinct biochemical profiles, defined by unique profiles of lipids, nucleotides, and amino acids. Collectively, these data underscore the critical role of specific K. pneumoniae secreted metabolites to pathogen survival and host immune modulation. The combined approach effectively resolves functionally relevant secretome fractions, offering new avenues for identifying diagnostic and therapeutic targets for multidrug-resistant infections. Full article

Colorectal cancer (CRC) remains a leading cause of cancer morbidity and mortality worldwide, with nearly one quarter of patients presenting with metastatic disease at diagnosis. The epidermal growth factor receptor (EGFR) plays a central role in CRC pathogenesis through activation of downstream RAS/RAF/MAPK and PI3K/AKT/mTOR signaling pathways, and has become a major therapeutic target. Anti-EGFR monoclonal antibodies, cetuximab and panitumumab, have demonstrated survival benefit in selected patients, particularly those with left-sided, RAS wild-type tumors. However, primary and acquired resistance limit their efficacy, underscoring the need for predictive biomarkers and novel strategies. This review synthesizes current knowledge of EGFR biology, therapeutic integration, and biomarker development, including RAS and BRAF mutations, MSI status, HER2 amplification, EGFR ligands (AREG/EREG), consensus molecular subtypes, and liquid biopsy applications. We also discuss mechanisms of resistance such as pathway reactivation, receptor mutations, and epithelial-to-mesenchymal transition, alongside emerging approaches, including combination regimens, ctDNA-guided rechallenge, and genotype-specific inhibitors. Collectively, these insights highlight the evolving landscape of precision oncology in CRC and the importance of molecular stratification to optimize EGFR-targeted therapy and overcome resistance. Full article

The radial growth of the tree stem reflects tree responses to climate change. This study examines the response of Fagus orientalis to more than half a century of climate dynamics in Armenia using a dendrochronological approach. Two forest stands were analyzed: one geographically isolated stand in the arid southern part of the country and one stand in the mesic northern mountainous region, where the main beech forests are distributed. The study period was divided into two phases (1965–1993 and 1994–2023). Climate dynamics were assessed by the months of the biological year, from October of the previous year to the end of September of the current growing season. Substantial warming trends were detected at both stands, except in November, December, and April, and in July in the northern part of Armenia. Between periods, the mean ring width increased from 1.67 mm to 2.14 mm at the northern stand, while decreasing from 1.95 mm to 0.89 mm at the southern stand. Despite climate warming and declining precipitation, some study trees exhibited increased (northern) or stable (both stands) radial growth. Comparison of the two periods revealed pronounced ecological and tree-specific variability in climate–growth relationships, including shifts in correlation strength and sign reversals. These patterns were primarily driven by climate sensitivity rather than age-related effects. The results provide valuable insights for conserving the southern stand and may support assisted migration strategies for F. orientalis toward the southern margin of the F. sylvatica distribution range. Full article

Scots pine (Pinus sylvestris L.) spans most of Eurasia, yet southern and mountainous populations may retain distinctive genetic components shaped by long-term isolation and complex postglacial dynamics. We genotyped 186 trees from four Scots pine stands in Armenia (AM1-AM4) and reference stands from Germany, Russia and Montenegro with the PiSy50k SNP array and integrated these data with published European array datasets from Finland, Poland and the Baltic region. After quality checks and conservative SNP filtering, 627 individuals from 47 populations and 3659 SNP loci were retained. Within-population diversity was generally high; Armenian stands AM2–AM4 were among the most diverse, whereas AM1 showed reduced diversity and the highest differentiation relative to the remainder of the dataset (FST vs. rest = 0.0047). Direct pairwise F_ST and hierarchical AMOVA confirmed pronounced heterogeneity among Armenian stands, with AM1 the most differentiated stand, AM2 and AM4 closest to the broader Eurasian background, and AM3 intermediate. Principal component analysis (PC1 = 1.42%, PC2 = 0.76%) again separated AM1 strongly from all non-Armenian samples, while AM2 overlapped with the central/eastern European cluster and AM3 and AM4 combined continental-like and AM1-like individuals. Structure-like inference with LEA/sNMF showed a broad cross-entropy plateau from approximately K = 4 to K = 6; we therefore use K = 5 as a practical summary, which highlighted a dominant AM1-associated ancestry component and variable continental admixture in AM2–AM4. KING kinship estimates provided little evidence for within-stand family clustering in Armenian stands; no second-degree-or-closer pairs were observed in AM1–AM4. Together, the results reveal pronounced heterogeneity among Armenian Scots pine stands and identify AM1 as a highly differentiated but unresolved genomic component, providing a genomic baseline to support conservation planning, provenance evaluation and the management of forest reproductive material in the Lesser Caucasus. Full article

Tendon healing is often hindered by unresolved inflammation and dysregulated immune responses, highlighting the need for innovative regenerative strategies. This study developed an immune-informed platform by functionalizing validated 3D tendon-mimetic poly(lactide-co-glycolide) (PLGA) scaffolds with immunomodulatory conditioned media (CM), referred to as CM_INF to emphasize its anti-inflammatory and immunomodulatory properties, derived from ovine amniotic epithelial stem cells (AECs), offering a potential cell-free therapeutic solution. Three functionalization methods were compared: physical adsorption, and hydrochloric acid (HCl) or sodium hydroxide (NaOH) pre-treatments. FT-IR spectroscopy and protein adsorption analyses identified NaOH as the most effective method, enhancing retention and release of Amphiregulin (AREG), an AEC key immunomodulatory protein. Kinetic studies revealed a sustained, controlled release of AREG over 7 days (d) from CM_INF-functionalized scaffolds (3D-CM_INF), preserving bioactivity. Functionally, 3D-CM_INF scaffolds significantly suppressed T-cell activation and peripheral blood mononuclear cell (PBMC) proliferation. The released CM from 3D-CM_INF (CM_R) exhibited time-dependent immunomodulatory effects: early T-cell inhibition (6–72 h) and delayed suppression of PBMC proliferation (48 h–7 d). Macrophage polarization analysis revealed a shift towards the pro-regenerative M2 phenotype, with increased expression of M2 over M1 markers in 3D-CM_INF-adherent cells. Flow cytometry confirmed a preferential induction of regulatory M2b macrophages alongside reductions in pro-inflammatory M1 and pro-fibrotic M2a subsets. These results demonstrate that 3D-CM_INF scaffolds can finely modulate immune responses, balancing inflammatory and reparative cues relevant to early tendon healing processes. This platform, integrating structural and immunomodulatory elements, presents a promising, cell-free, and translational immunoengineering strategy to control inflammation and support tendon repair. Full article

The secretome of ESKAPE pathogens contains numerous bioactive molecules that play a key role in pathogenesis and the formation of an immunosuppressive microenvironment. However, analyzing this complex chemical composition presents significant methodological challenges. In this study, we propose a combined approach integrating chromatographic fractionation of cell-free supernatants with Raman spectroscopy to deconstruct the secretome of the clinically relevant Gram-negative pathogen—Enterobacter spp. Chromatographic separation of the Enterobacter spp. supernatant into seven fractions reduced spectral congestion and enabled identification of fraction 3 as having a unique metabolite profile, enriched in peptides (including tryptophan- and tyrosine-containing structures), nucleic acids, polysaccharides, and putative glutathione-like compounds. Notably, fraction 3 lacked markers of phenylalanine and sterol-like lipids, highlighting its distinct composition. Compared to conventional mass spectrometry and nuclear magnetic resonance, our hybrid strategy offers minimal sample preparation, preserves sample integrity for repeated analysis, avoids ionization bias, and is fully compatible with aqueous biological matrices—critical advantages for profiling labile or low-abundance metabolites in native secretomes. These findings demonstrate that the combination of preparative chromatography and Raman spectroscopy effectively resolves complex bacterial secretomes and identifies fractions potentially carrying key virulence or signaling functions. Full article

Essential tremor (ET) negatively affects neuromuscular control and hand function in older adults. Resistance exercise may enhance musculoskeletal and functional capacity, yet its modality-specific effects in ET remain unclear. This study compared the effects of home-based and aquatic resistance training on tremor severity, manual dexterity, and handgrip strength in older adults with ET. Twenty-seven participants were randomly assigned using block randomization to a home-based resistance exercise group (HBREG; n = 9), an aquatic resistance exercise group (AREG; n = 9), or a control group (CG; n = 9). Both intervention groups completed an 18-session resistance exercise program, with initial sessions supervised and subsequent sessions performed independently under regular monitoring. Tremor severity (FTMTRS), manual dexterity (Nine-Hole Peg Test), and handgrip strength were assessed pre- and post-intervention. Within-group changes were analyzed using the Wilcoxon signed-rank test and between-group differences using the Kruskal–Wallis test with Bonferroni-adjusted Mann–Whitney U tests (p < 0.05). Both HBREG and AREG demonstrated significant improvements in drawing and pouring tremor tasks, manual dexterity, and handgrip strength compared with the control group, with large effect sizes across outcomes. No significant differences were observed between the two exercise modalities, and no improvement occurred in the highest-difficulty spiral-B task. These findings indicate that both home-based and aquatic resistance training are safe and effective non-pharmacological strategies for reducing tremor severity and enhancing upper-extremity function in older adults with ET. Full article

Elevated sodium concentrations are commonly observed in tumors and sites of inflammation. Previous studies have shown that high salt levels modulate the phenotype and function of CD4⁺ and CD8⁺ T cells, regulatory T cells, and macrophages. In this study, we performed transcriptomic studies that revealed profound alterations in the neutrophil transcriptome upon high salt exposure, with changes that significantly exceeded those triggered by conventional agonists. By integrating transcriptomic data with functional assays, our findings suggest that high salt-induced neutrophil activation involves mitochondrial ROS production, which subsequently activates p38 MAPK and engages FOS-, Bruton’s tyrosine kinase (BTK)-, and cyclooxygenase 2 (COX2)-dependent pathways. Remarkably, the plasticity of the neutrophil transcriptome in response to high salt was further evidenced by the upregulation of genes typically associated with other cell types, including semenogelin 1 (SEMG1), intercellular adhesion molecule-4 (ICAM4), tripartite motif69 (TRIM69), amphiregulin (AREG), oncostatin (OSM), and transducer of ERBB2-1 (TOB1), suggesting a broader role for neutrophils in different biological processes beyond their participation in innate immunity. Full article

Vietnam faces a hyperendemic burden of hepatitis B virus (HBV) infection, but the prevalence of occult HBV infection (OBI) and its underlying molecular mechanisms in healthy populations remain poorly understood. This study aimed to characterize the serological and molecular HBV profile of a healthy Vietnamese adult cohort in Southern Vietnam. We assessed the prevalence of occult HBV infection (OBI) and HBsAg-positivity (serving as a proxy for probable chronic infection). In this cross-sectional study, 397 healthy adults from Southern Vietnam underwent serological screening for HBsAg, anti-HBs, and anti-HBc. All participants were screened for HBV DNA using a high-sensitivity PCR assay (LOD ≥ 5 IU/mL). For all viremic cases, the full Pre-S/S region was sequenced to determine genotype and characterize escape mutations. We uncovered a high prevalence of both HBsAg-positivity (17.6%) and OBI (9.3% HBsAg-negative, HBV DNA-positive). Serological analysis revealed a massive, age-dependent reservoir of past exposure (63.7% anti-HBc) characterized by a high and increasing prevalence of the anti-HBc only profile (31.5%), a key serological marker for OBI. This trend contrasted sharply with a steep age-related decline in protective anti-HBs. The viral landscape was dominated by genotypes B (73.8%) and C (26.2%), with sub-genotypes B4 and C1 being the most prevalent. Critically, individuals with OBI carried a significantly higher burden of S gene escape mutations compared to those with HBsAg-positivity (p < 0.001). Canonical escape variants, including sG145R (21.6%), sK141R/T/E/Q (24.3%), and sT116N/A/I/S (18.9%), were exclusively or highly enriched in the OBI group. A LASSO-logistic model based on this mutational profile successfully predicted occult infection with high accuracy (AUC = 0.83). A substantial hidden reservoir of occult HBV infection exists within the healthy adult population of Vietnam, driven by a high burden of S gene escape mutations. These findings highlight the significant limitations of conventional HBsAg-only screening. They also underscore the need for comprehensive molecular surveillance to address the true scope of HBV viremia, hopefully enabling a reduction in hidden transmission of clinically significant viral variants. Full article

Single-cell RNA-sequencing has transformed our understanding of alveolar epithelial type 2 (AT2) cells and alveolar lipofibroblasts (LIFs) during lung injury and repair. Both cell types undergo dynamic transitions through intermediate states that determine whether the lung proceeds toward regeneration or fibrosis. Emerging evidence highlights reciprocal paracrine signaling between AT2/AT1 transitional cells and LIF-derived myofibroblasts (aMYFs) as a key regulatory axis. Among these, amphiregulin (AREG)–EGFR signaling functions as a central profibrotic pathway whose inhibition can restore alveolar differentiation and repair. The human WI-38 fibroblast model provides a practical platform to study the reversible LIF–MYF switch and screen antifibrotic and pro-regenerative compounds. Candidate therapeutics including metformin, haloperidol and FGF10 show promise in reprogramming fibroblast and epithelial states through metabolic and signaling modulation. Integrating WI-38-based assays, alveolosphere co-cultures, and multi-omics profiling offers a translational framework for identifying interventions that halt fibrosis and actively induce lung regeneration. This review highlights a unifying framework in which epithelial and mesenchymal plasticity converge to define repair outcomes and identifies actionable targets for promoting alveolar regeneration in chronic lung disease. Full article