Search Results (18,446)

Background: Late-onset neonatal sepsis (LONS) remains a major cause of morbidity in preterm neonates admitted to the neonatal intensive care unit (NICU), yet the contribution of vitamin D status to neonatal infectious susceptibility remains uncertain. Objective: To evaluate clinical and demographic variables and serum vitamin D levels assessed at birth in preterm neonates with and without LONS. Methods: A retrospective observational cohort study was conducted in a tertiary NICU in northeastern Mexico between May 2023 and October 2024. Preterm neonates (<37 weeks of gestation) with serum 25(OH)D measured within the first hour of life were included. Vitamin D status was classified as sufficient (≥30 ng/mL), insufficient (20–29 ng/mL), or deficient (<20 ng/mL). LONS was defined as sepsis occurring after 72 h of life. Comparisons between neonates with and without LONS were performed using Fisher’s exact test for categorical variables and Student’s t-test or Mann–Whitney U test for continuous variables, as appropriate. Results: Twenty-nine preterm neonates were included (mean gestational age: 32.0 ± 2.6 weeks; mean birth weight: 1748 ± 545 g). The mean serum 25(OH)D level at birth was 35.5 ± 13.0 ng/mL. LONS occurred in 31% (9/29) of neonates, of which 55% were microbiologically confirmed. No significant differences were observed in vitamin D levels between neonates with and without LONS (35.0 ± 12.0 vs. 35.7 ± 13.7 ng/mL; p = 0.899). Vitamin D deficiency was not associated with LONS (OR 1.13, 95% CI 0.09–14.28). The prevalence of vitamin D deficiency was low (10%) in this cohort. Conclusions: A clear association between serum 25(OH)D levels at birth and the development of LONS could not be demonstrated in this small exploratory cohort. Given the limited sample size and low prevalence of vitamin D deficiency, further multicenter prospective studies are required to better understand the potential relationship between vitamin D status and neonatal infectious outcomes. Full article

Atypical porcine pestivirus (APPV) is a pestivirus that infects swine and has been associated with congenital tremor (CT) in piglets in the field, as well as those born to experimentally infected sows. However, APPV has also been detected in swine of various ages without clinical signs. Experimental and field studies have demonstrated prolonged detection of viral RNA in serum, secretions, and tissues. For this work, nine gilts from a longitudinal APPV field study were selected based on birth in CT-positive litters and evidence of prolonged detection of virus in the sera. These six-month old animals were transported to a research facility for further sampling, breeding, and necropsy. The gilts were placed in contact with naïve animals for approximately one month at two different timepoints, prior to and during gestation, to assess transmission. After farrowing, litters were monitored for CT and tested for APPV. Following arrival, serum samples were PCR-negative for APPV; however, the gilts consistently tested positive in oral fluids and had detectable APPV in the cerebellum months later at necropsy. The gilts had a delayed humoral immune response, with the majority not seroconverting until approximately ten months of age. There were PCR-positive tissues and evidence of seroconversion in animals from both contact groups; however, none of the litters tested PCR-positive for APPV. These findings improve our understanding of the temporal dynamics and transmission potential of APPV infection and can help guide control measures to reduce viral spread. Full article

Background: Vision is a key sensory system for postural regulation; however, the effects of degraded visual input and complete visual occlusion on static balance are not fully understood. The aim of the present study was to compare postural control during single-leg stance under two reduced-vision conditions (eyes open in darkness vs. complete visual occlusion) in healthy young adults and examine the potential influence of sex and mild visual deficits. Materials and Methods: This within-subject laboratory study included 42 healthy young adults (21 males, 21 females; mean age 20.67 ± 0.48 years). Participants performed three valid 20 s single-leg stance trials on a force platform under two visual conditions: eyes open in darkness and complete visual occlusion using an opaque mask. The order of conditions was randomized and counterbalanced, and the mean value of the three valid trials under each condition was used for analysis. Postural sway outcome variables included CoP Area, Oscillation Width, Oscillation Height, Total Displacement, and Mean Velocity. A two-way mixed-design ANOVA examined the effects of visual condition and sex. Additional mixed ANCOVA analyses were performed using body weight as a covariate to verify whether the sex-related findings remained after adjustment for body weight. Exploratory subgroup analyses based on mild visual deficits were performed using independent-samples t-tests. Results: No significant overall main effect of visual condition was observed for any postural sway variable (all p > 0.05). However, a significant condition × sex interaction was found for CoP Area (F(1,40) = 9.910, p = 0.003, η²p = 0.199), indicating different response patterns between males and females across conditions. Significant main effects of sex were also found for Total Displacement (F(1,40) = 9.212, p = 0.004, η²p = 0.187) and Mean Velocity (F(1,40) = 9.090, p = 0.004, η²p = 0.185), with males showing higher values overall. The sex-related findings for CoP Area, Total Displacement, and Mean Velocity remained significant after adjustment for body weight. No significant sex effects were found for Oscillation Width or Oscillation Height, and no significant differences were observed between participants with and without mild visual deficits in either condition (all p > 0.05). Conclusions: Altered visual input did not produce a uniform overall effect on postural sway during single-leg stance in healthy young adults. Instead, the findings indicate a more differentiated pattern, with a sex-specific response for CoP Area and overall sex-related differences in Total Displacement and Mean Velocity that were not explained by body weight. Mild visual deficits were not associated with significant balance alterations under the present experimental conditions. These findings support a more nuanced interpretation of postural regulation under reduced visual input and highlight the importance of considering individual characteristics, particularly sex, in balance assessment. Full article

Background: This study aimed to evaluate referral reasons, distribution of allergic diseases, atopic status, and comorbidity associations among patients aged 65 years and older presenting to a tertiary allergy clinic. Methods: This retrospective study included all geriatric patients (≥65 years) who attended the Immunology and Allergy outpatient clinic at Ankara Bilkent City Hospital between January 2024 and December 2025. Demographic characteristics, comorbidities, referral complaints, and allergic diagnoses were recorded. Allergen sensitization was assessed using skin tests and/or allergen-specific IgE measurements. Results: A total of 1302 geriatric patients were included (mean age 70.9 years; 59.8% female). At least one comorbidity was present in 62.6% of patients, with hypertension being the most common(39.4%). The leading referral complaints were rhinorrhoea/sneezing (22.8%), pruritus (19.1%), drug allergy/adverse drug reactions (14.8%), and chronic urticaria (10.9%). The most common diagnoses were rhinitis (63.2% non-allergic), non-allergic pruritus, drug allergy, and chronic urticaria. Among inhalant allergens, pollen sensitivity (42.2%) was most frequent, followed by house dust mite (32.5%). The most frequently implicated drug groups were antibiotics (42.4%) and analgesics (21.7%). Chronic urticaria and ACE inhibitor-associated angioedema showed significant gender differences: 68.6% female (p = 0.001) and 66.7% male (p = 0.008), respectively. Patients with asthma, rhinitis, or angioedema frequently had comorbid conditions (91.1%, 55.8%, and 83.7%, p = 0.001, p = 0.013, and p = 0.001, respectively). Conclusions: Allergy clinic presentations in elderly patients reflect a broad clinical spectrum, including non-allergic conditions, frequent drug-related reactions in elderly patients with multiple comorbidities, and age-related immunological changes alongside atopic diseases. A comprehensive, individualized diagnostic approach is essential when evaluating allergic complaints in the geriatric population. Full article

Background/Objectives: KRAS mutations are among the most common oncogenic driver alterations in non-small cell lung cancer (NSCLC) and define a biologically heterogeneous disease. In the current era of molecular oncology, with targeted therapies increasingly incorporated into clinical practice, the prognostic relevance of individual KRAS mutation subtypes and their relationship with immune biomarkers such as programmed cell death ligand 1 (PD-L1) require further clarification. This study aimed to evaluate the prognostic impact of KRAS mutation subtypes and their association with PD-L1 expression in patients with NSCLC. Methods: In this retrospective analysis, 150 patients with KRAS-mutant NSCLC who underwent next-generation sequencing at Trakya University Faculty of Medicine between January 2015 and December 2023 were included. Clinicopathological features, KRAS mutation subtypes, PD-L1 expression, and survival outcomes were assessed. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method, and prognostic factors were evaluated using Cox regression analyses. Results: KRAS G12C was the most frequent subtype (40.7%), followed by G12V (20.7%) and G12D (14.7%). OS differed significantly among KRAS mutation subtypes (log-rank p = 0.007), with median OS values of 18 months for G12D, 11 months for G12C, 11 months for other rare variants, 9 months for G12A and G12V, and 5 months for G13. PD-L1 positivity was significantly higher in KRAS G12C tumors compared with non-G12C subtypes and remained independently associated with improved OS in multivariate Cox regression analysis (HR = 0.622; 95% CI, 0.426–0.907; p = 0.014). In multivariate analysis, age, ECOG performance status, disease stage, and PD-L1 positivity were independent prognostic factors, whereas KRAS mutation subtype did not retain independent prognostic significance. Conclusions: These findings suggest that KRAS-mutant NSCLC represents a clinically and molecularly heterogeneous subgroup and that integrating KRAS mutation subtypes with immune biomarkers may support more refined prognostic stratification. Full article

Background/Objectives: The sella turcica is a key anatomical landmark due to its close relationship with the pituitary gland and surrounding structures. This study aimed to compare morphometric characteristics of the sella turcica in autopsy cases according to sex and to develop machine learning (ML)-based sex estimation models using these measurements. Methods: This study included 230 individuals (115 males, 115 females). Sella turcica morphometric measurements (length, depth, anteroposterior, and transverse diameters) were analyzed. In addition, associations with age, height, and weight were evaluated. Sex differences and correlations were assessed using non-parametric tests. Generalized additive models were applied to evaluate non-linear effects of height and weight, and ML algorithms (LR, RF, SVM, XGBoost) were used for sex classification with 10-fold cross-validation. Results: Data from 230 individuals (115 males, 115 females) were analyzed. All sella turcica dimensions were significantly greater in males (p < 0.001). Height showed strong positive correlations with all measurements, whereas weight showed weaker associations and age was not significant. Generalized additive models demonstrated high performance for length and anteroposterior diameter (adjusted R² ≈ 0.956), high performance for transverse diameter (R² = 0.936), and moderate performance for depth (R² = 0.700), with significant non-linear effects of height and weight. ML models achieved high accuracy (>95%), with SVM performing best (accuracy: 0.991; AUC: 0.997), and transverse diameter identified as the most important predictor. Conclusions: Sella turcica morphometry demonstrates strong sexual dimorphism and is primarily influenced by body size parameters, particularly height. Non-linear modelling approaches such as GAM effectively capture complex anatomical relationships, while ML models, especially SVM, provide promising sex estimation. Among all variables, transverse diameter emerges as the most robust and consistent predictor, highlighting its potential utility in forensic and anthropological applications. Full article

Semaglutide represents a unique therapeutic option for patients with type 2 diabetes mellitus (T2DM), being the first and currently only glucagon-like peptide-1 receptor agonist (GLP-1RA) available in both subcutaneous and oral formulations. This study aimed to compare the effectiveness of oral versus subcutaneous (sc) semaglutide on metabolic parameters and cardiovascular risk factors in T2DM patients. This is a retrospective real-world study including adult patients with T2DM taking oral or sc semaglutide followed at the ASUGI Diabetes Center. We analyzed data from 434 patients (median age 70 years, diabetes duration 13 years), treated with oral (n = 232) or sc (n = 202) semaglutide. The oral formulation had a higher discontinuation rate. Among these patients, 130 patients in the oral group and 145 in the sc group had an 18-month follow-up. When comparing these groups, patients taking sc semaglutide had a significantly higher baseline BMI. However, multivariate linear regression models suggested that both formulations were comparably effective in reducing HbA1c and BMI, with baseline values being the primary predictors of response. To address BMI imbalances, propensity score matching was performed, identifying 55 matched pairs. Both oral and sc semaglutide reduced HbA1c and BMI and there were no significant differences in the median change in HbA1c and BMI between groups. Interestingly, oral semaglutide was associated with a significantly greater reduction in diastolic blood pressure compared to the sc formulation. Furthermore, concomitant therapy with SGLT2 inhibitors significantly enhanced the reduction in total and LDL cholesterol. Oral and subcutaneous semaglutide show comparable effectiveness in lowering HbA1c and BMI in a real-world setting. Full article

IDH-wildtype glioblastoma remains the most aggressive primary brain tumor, with a median overall survival (OS) of 14–16 months despite maximal treatment. A small subset of patients, however, survive beyond 30 months, suggesting distinct underlying biological features. The aim of this pilot study was to explore whether selected molecular alterations detectable by FISH show differing distribution patterns between patients with prolonged and poor survival in IDH-wildtype glioblastoma. We retrospectively analyzed 20 patients with newly diagnosed primary IDH-wildtype glioblastoma who underwent gross-total resection followed by standard radiotherapy and temozolomide treatment between 2016 and 2022. Patients were categorized into two predefined groups according to survival outcomes: long-term survivors (OS > 30 months) and short-term survivors (OS < 10 months). Fluorescence in situ hybridization (FISH) was used to evaluate alterations in ATRX, BRAF, and PIK3CA. MGMT promoter methylation, EGFR amplification, and TERT promoter mutation status were obtained from routine diagnostic reports. Because survival groups were intentionally pre-selected as extreme phenotypes, time-to-event analysis was not appropriate. Therefore, statistical comparisons were performed using Fisher’s exact test and multivariable logistic regression with long-term versus short-term survival as a binary outcome. Short-term survivors had a significantly higher median age (57.5 vs. 46.5 years, p = 0.043) and a higher rate of EGFR amplification (100% vs. 50%, p = 0.033). Strikingly, combined BRAF and PIK3CA alterations (predominantly polysomy) were detected in 8 out of 10 (80%) long-term survivors, compared to 0 out of 10 (0%) short-term survivors (p = 0.0007). In multivariable logistic regression adjusted for age and MGMT promoter methylation, BRAF/PIK3CA alteration remained strongly associated with long-term survival, though the effect size was mathematically inflated due to perfect separation (0 events in Group B). BRAF and PIK3CA copy number alterations were observed exclusively in long-term survivors in this small exploratory cohort, suggesting a possible association with prolonged survival. However, given the limited sample size, the selection of extreme survival groups, and the predominance of chromosomal polysomy detected by FISH, these findings should be interpreted as hypothesis-generating only. Further validation in larger cohorts using high-resolution genomic methods is warranted. Full article

Background and Objectives: This research aimed to compare Type D personality characteristics and self-esteem between individuals with chronic NSLBP and healthy controls, while also exploring their relationships with functional status, psychological symptoms, and quality of life within the patient group. Materials and Methods: In this cross-sectional investigation, 34 patients with chronic NSLBP were compared with 34 healthy controls with similar age and sex distribution. Pain intensity was quantified via the Visual Analog Scale (VAS), while functional impairment was evaluated using the Oswestry Disability Index (ODI). Psychological profiling included the Type D Scale-14 (DS14) for personality traits, the Rosenberg Self-Esteem Scale (RSES) for self-worth, and the Hospital Anxiety and Depression Scale (HADS) for emotional distress. Health-related quality of life was captured through the 12-Item Short Form Health Survey (SF-12). Results: Type D personality was significantly more prevalent in the NSLBP group than in controls (50% vs. 20.6%, p = 0.011). Patients with NSLBP had significantly higher negative affectivity (NA) scores (p < 0.001) and anxiety scores (p = 0.007) and lower SF-12 Physical Component Summary scores (p < 0.001) than controls. Pain intensity and disability were positively correlated with Type D personality traits, particularly NA and the Type D composite score. In exploratory subgroup analyses, patients with Type D personality also had higher pain intensity, disability, anxiety, and depression scores and lower SF-12 Mental Component Summary (MCS) scores than those without Type D personality. In adjusted regression analyses within the NSLBP group, Type D personality was associated with higher VAS (p = 0.004) and ODI scores (p = 0.007) and lower SF-12 MCS scores (p = 0.003). Conclusions: Type D personality characteristics were more frequent in patients with chronic NSLBP than in healthy controls and were associated with higher pain intensity, greater disability, higher anxiety and depressive symptom scores, and poorer mental quality-of-life scores within the patient group. In contrast, self-esteem did not differ significantly between patients and controls. Due to the inherent constraints of a cross-sectional framework and the potential construct redundancy between NA and emotional distress, the current results signify correlational links rather than definitive causality. Consequently, subsequent prospective research is vital to delineate the temporal dynamics and the long-term predictive value of Type D personality traits in the progression of chronic NSLBP. Full article

Background: University students often face significant psychological challenges and lifestyle disruptions that may compromise their mental resources and health-related quality of life (HRQoL). Although associations between physical activity (PA) and mental health have been widely reported, few studies have integrated different PA intensities, sedentary behavior, and psychological resources jointly related in one analytical model. Objective: This study investigated the relationships among vigorous (VPA), moderate (MPA), and light (LPA) physical activity, sedentary behavior (SB), resilience (RES), self-esteem (SE), and HRQoL in a sample of Chinese university students. Methods: A cross-sectional survey included 1560 university students from six universities in China, with a mean age of 19.43 ± 1.15 years; the sample comprised 434 males (27.8%) and 1126 females (72.2%). Relationships among the variables were tested using path analysis within a structural equation modeling framework. Results: Greater PA engagement was related to higher RES, SE, and HRQoL, whereas SB was not significantly associated with RES. All three PA intensities were positively associated with RES, although the magnitude of these associations varied. In addition, RES was also related to higher SE and HRQoL, and SE was related to higher HRQoL. Conclusions: These findings suggest that PA is associated with psychological resources and HRQoL among university students. Longitudinal and intervention studies are needed to determine the directionality and mechanisms underlying these relationships. Full article

Background: Vascular adverse events (VAEs) related to facial filler injections are rare but potentially severe complications. Doppler ultrasound has emerged as an adjunct imaging tool for evaluating vascular compromise; however, Doppler findings in facial VAEs remain insufficiently characterized. Objectives: To characterize Doppler ultrasound findings associated with filler-related facial VAEs and to assess whether Doppler patterns differ according to prior hyaluronidase administration. Methods: This international multicenter retrospective observational study included 100 patients with clinically diagnosed facial VAEs following filler injections between May 2022 and April 2025. Doppler ultrasound findings were analyzed, including absent flow in perforators and major arteries, compensatory flow, abnormal waveforms, increased peak systolic velocity (PSV), and absence of Doppler abnormalities. Patients were categorized according to hyaluronidase administration prior to ultrasound evaluation. Descriptive statistics and comparative analyses were performed. Results: One hundred patients (median age, 38 years; IQR: 30–50; 88 women) were evaluated. The most frequent Doppler ultrasound findings were absent flow in perforators (42%) and major arteries (35%), followed by compensatory flow (26%), string sign (18%), flow diversion (16%), and increased peak systolic velocity (16%). No Doppler abnormalities were observed in 12% of cases, while tardus–parvus (9%) and staccato waveform (8%) were less frequent. Doppler ultrasound findings did not differ significantly between patients who received hyaluronidase before imaging and those who did not (all p > 0.05). The dose of hyaluronidase varied substantially. Livedo reticularis, blanching, and pain were the most common clinical findings. Central facial arterial territories, particularly the perioral, nasolabial fold, nasal, and glabellar regions, were most commonly involved. Conclusions: Filler-related facial VAEs show recognizable Doppler ultrasound patterns, and the identification of these patterns may improve localization of vascular occlusion and support ultrasound-guided hyaluronidase administration, potentially enabling more targeted delivery with lower doses. Full article

Multiple Sclerosis (MS) is a neuroinflammatory disorder in which genetic and environmental factors contribute to disease onset. Evidence implicates the inflammasome pathway in MS pathophysiology. However, the interaction between inflammasome-related genetic variants and 25-OH-vitamin D₃ (25(OH)D₃) levels remains unclear. 105 MS patients and 109 healthy controls were enrolled. Genotyping of NLRP3 (rs10754558, rs3806265) and NLRC4 (rs479333) polymorphisms was performed using real-time PCR. Serum 25(OH)D₃ levels were measured by high-performance liquid chromatography. Clinical severity was assessed using the Expanded Disability Status Scale (EDSS), Multiple Sclerosis Severity Score (MSSS), annualized relapse rate (ARR), and age at onset. MS patients showed significantly lower serum 25(OH)D₃ levels than controls. Genotype distributions did not differ significantly under an additive model; however, the NLRP3 rs10754558 GG genotype was more frequent in MS patients under a recessive model and was significantly associated with disease status after adjustment for sex. Subjects carrying the GG genotype also had significantly lower serum 25(OH)D₃ levels than CC/CG carriers, independently of sex. No significant associations were observed for NLRP3 rs3806265 or NLRC4 rs479333, and none of the investigated variants was associated with EDSS, MSSS, ARR, or age at onset. The NLRP3 rs10754558 polymorphism may be associated with MS susceptibility and reduced circulating vitamin D levels, suggesting a potential link between inflammasome-related genetic variability and immunometabolic regulation in MS. Full article

Obesity is a major global health challenge characterized by chronic low-grade inflammation, oxidative stress, and an increased risk of cardiometabolic disorders. Although sex-related differences in inflammatory and redox biomarkers have been reported in obese populations, the molecular mechanisms underlying this heterogeneity remain incompletely understood. In this study, we applied a proteomics-based approach to investigate urinary extracellular vesicles from 45 obese individuals (BMI 30–40 kg/m²; age 50–70 years) in order to identify molecular signatures associated with metabolic dysregulation. Shotgun proteomics analysis performed by nanoLC–MS/MS enabled the identification of 3822 proteins. Hierarchical clustering of proteomic profiles revealed two distinct molecular groups, predominantly enriched in males (Group I) and females (Group II). Label-free quantitative analysis identified 466 differentially abundant proteins between the two clusters. Functional enrichment analysis highlighted pathways associated with immune response, metabolic regulation, and redox homeostasis, including glycolysis/gluconeogenesis, lysosome activity, leukocyte transendothelial migration, and glutathione, cysteine and methionine metabolism. Notably, proteins related to ferroptosis were enriched, suggesting the involvement of iron-dependent oxidative cell death mechanisms in the metabolic imbalance observed in a subset of subjects. Furthermore, the non-enzymatic glycosylation of urinary proteins was significantly higher in Group I compared with Group II (p = 0.0002), indicating increased formation of advanced glycation products in individuals with a more pronounced pro-oxidant state. Preliminary follow-up data suggested a higher incidence of pathological events, including cardiovascular complications, among individuals belonging to Group I. Overall, these findings demonstrate that urinary proteomic profiling can identify distinct molecular phenotypes among obese individuals and highlight oxidative stress, ferroptosis, and protein glycation as potential determinants of metabolic vulnerability, supporting the use of non-invasive proteomic approaches for improved risk stratification in obesity. Full article

Evidence remains limited on the interconnections between developmental coordination disorder (DCD), health-related physical fitness—including body composition, flexibility, strength of lower body, and cardiorespiratory fitness—and objectively measured physical activity (PA) in school-aged children. This study aimed to (1) examine differences in physical fitness and PA between children with and without DCD and (2) investigate whether physical fitness functions as a mediator in the association between DCD and PA in school-aged children. Sixty-three children aged 6.5–8 years (12 DCD, 19.05%) who provided valid data were enrolled. Mediation analysis was conducted using the PROCESS macro for SPSS. Flexibility significantly mediates the relationship of DCD to vigorous PA (VPA) (effect = 3.202, bootstrap SE = 1.682, 95% bootstrap CI = 0.463, 7.078), as well as DCD to moderate-to-vigorous (MVPA) (effect = 5.194, bootstrap SE = 2.903, 95% bootstrap CI = 0.434, 11.778). Additionally, there was a significant mediating effect of lower muscle strength on the relationship between DCD and VPA (effect = −1.943, bootstrap SE = 1.297, 95% bootstrap CI = −5.112, −0.021), and DCD and counts per minute (CPM) in axis 2 (effect = −34.388, bootstrap SE = 20.212, 95% bootstrap CI = −80.819, −1.353). The findings highlight flexibility and lower-body strength as potential mechanisms underlying the association between DCD and PA participation. These factors may represent candidate intervention targets; however, their roles require confirmation in larger samples and longitudinal designs. Full article

We used thermodynamic modeling methods to calculate the stability of auroselenide AuSe_(s) in hydrothermal solutions at different temperatures (25–350 °С), pressures (1–165 bar), salinities (0–5 m NaCl), and acidity–alkalinity (0.00001–0.1 m НCl or NaОН). Gold selenide dissolves congruently in near-neutral solutions. In acidic chloride solutions, AuSe_(s) dissolves incongruently to form selenium Se_(s,l), and in alkaline solutions, to form gold Au_(s). Gold selenide has a low solubility at temperatures of 25–200 °С. With increasing temperature, the solubility of AuSe_(s) increases and at 350 °С the concentration of dissolved gold in highly acidic solutions (without NaCl) reaches 10⁻⁶ m, while in near-neutral and alkaline solutions, it varies from 2·10⁻⁷ to 6·10⁻⁷ m. At concentrations of NaCl and HCl higher than 0.01 m, the solubility of AuSe_(s) increases by half an order of magnitude owing to the formation of gold chloride complexes. In low acidic, near-neutral, and alkaline solutions, gold hydroxocomplex is predominant. We constructed diagrams for the Au–Se–Н₂О system at various temperatures (25, 100, 200 and 300 °С), which show the stability fields of AuSe_(s), Au_(s) + AuSe_(s), Se_(s,l) + AuSe_(s) and Au_(s) on lg ƒO₂–pH. Gold chalcogenides are characteristic minerals of epithermal deposits. The relationships of auroselenide with native selenium and native gold and other minerals in the Au-Ag ores of the Gaching ore occurrence (Kamchatka Peninsula, Russia) and the Bleïda Far West Au-Pd deposit (Morocco) were studied. It was revealed that auroselenide occurs in the peripheral parts of native gold grains, and, less often, in the form of inclusions and intergrowths with other gold chalcogenides in the core of native gold grains. The presence of solidified microdroplets of composition ranging from Te_0.97Se_0.03 to Te_0.71Se_0.28S_0.01 and Se_0.58Te_0.41S_0.01 in the ore minerals at these and other golddeposits suggests participation of chalcogens existing at temperatures of 217–449 °C. The formation of auroselenide and other gold chalcogenides is likely with a decrease in temperature and neutralization of highly acidic or highly alkaline solutions, or with the participation of melts or chalcogen gas particles. The results of thermodynamic calculations are confirmed by the data on the composition of mineral associations with auroselenide from gold deposits. The presence of auroselenide in the ores from Au-Ag epithermal and other gold deposits with Au–Se–Te–S mineralization is predicted. Full article