At present, the main technological stages of oil production related to drilling operations require the use of a wide variety of drilling mud, which has a complex, multicomponent chemical composition. The drilling mud used and the resulting drilling waste must be safe for human health and the environment. The toxicity and hazard of drilling mud at this point in time remain poorly understood scientific problems and require detailing and studying in toxicological terms. The real degree of hazard and toxicity of drilling mud can only be determined by an experimental method, since its composition, which changes depending on the nature of the technological process and its degree of depletion, is not constant, which can change the toxicological properties. In an experiment conducted on adult male rats, under conditions of a single intragastric injection of drilling mud, new data were obtained regarding the parameters of its toxicity and hazard. The use of a wide variety of methods for determining lethal doses of drilling mud, including the probit analysis method, made it possible not only to substantiate the mean lethal dose of drilling mud but also other parameters of toxicity and survival of animals in the experimental groups. Features of eating behavior and body weight dynamics and the nature of the behavioral reactions revealed by the number and duration of stands and frequency and duration of grooming also indicate the presence of dose-dependent effects.

We performed a comparative observational study to evaluate HER2 protein expression in gastric cancer patients, and explored its correlations with clinicopathological characteristics. HER2 protein expression were assessed in formalin-fixed, paraffin-embedded stomach tissue by immunohistochemistry. Patient information was collected, and associations between clinicopathological factors and HER2 positivity (IHC score 3+ or 2 +) and HER2 negative expression (IHC score 1+or 0) were examined. A total of 109 patients with stomach cancer were included in the study. The level of positivity of Her2 expression, according to the recommendations of the National Comprehensive Cancer Network, in 57 cases (52.3%) showed “no membrane reactivity, in 19 (17.4%) “+” weak membrane reactivity, in 21 (19.3%) “++” cases the reaction was “moderate or lateral membrane and only in 12 cases (11.0%) expression was “+++”, which means “complete basolateral and correlated with various clinical and pathological parameters in patients with gastric cancer: older age, male gender, low-grade tumor. However, we did not find any significant correlation between overexpression of HER2 and tumor localization, histopathological differentiation of the tumor, as well as with the stage of the disease according to TNM.

Relevance: Numerous pathohistological classification systems are used to diagnose gastric cancer. Several studies have examined the relationship between the pathohistological characteristics of gastric cancer and various patient-related aspects, as well as factors influencing the course and prognosis of the disease. The Lauren classification system remains an accessible and widely used method for classifying gastric cancer, having been correlated with the clinical, histological, and molecular features of these tumors. This article presents a statistical analysis and evaluates the prognostic significance of the Lauren pathohistological classification system for gastric cancer, aiming to determine the most relevant classification for predicting overall survival in patients with this disease. ОРИГИНАЛЬНЫЕ ИССЛЕДОВАНИЯ 78 Онкология и Радиология Казахстана, №2 (76) 2025 The study aimed to investigate the clinicopathological characteristics of gastric cancer based on the Lauren classification and to assess its value in predicting overall survival of patients with gastric cancer. Methods: In this retrospective cohort study, a multidisciplinary team reviewed and discussed the data of 161 gastric cancer patients from Aktobe. All patients met the criteria of the diagnostic and treatment protocol for oncology patients of the Republic of Kazakhstan (Order No. 174 dated 21.11.2022) for surgical treatment and were newly diagnosed with gastric cancer of any stage at the age of 18 years or older. Data analysis was performed using SPSS v.25 (SPSS Inc., Chicago, Illinois, USA). The Pearson chi-square test was used to analyze the association between the Lauren classification and clinicopathological factors. The study was conducted at the Medical Center of West Kazakhstan Marat Ospanov Medical University based on pathomorphological reports collected from January 2020 to August 2024. Results: In the analysis of 161 gastric cancer cases, the Lauren classification showed a statistically significant association with the clinicopathological characteristics of the disease and patients’ overall survival. The diffuse type was associated with a more aggressive course and worse prognosis. The intestinal type was more frequently observed in patients with favorable prognostic features. Statistical processing using the Pearson chi-square test demonstrated significant survival differences between the Lauren subtypes. Conclusion: The Lauren classification remains a clinically significant and reliable tool for the prognostic stratification of gastric cancer patients. According to Lauren, the tumor type allows for assessing disease aggressiveness and prognosis, supporting justified therapeutic choices and a personalized approach to treatment.

Drilling fluids (DF) and the resulting drill cuttings (DC), widely used in oil production, pose a serious threat to the environment and human health. The issue of toxicity and danger of drilling fluids and drill cuttings still remains poorly understood and controversial. In this paper, we evaluate the dose-dependent effects of drilling fluid in an acute experiment with scientific substantiation of lethal doses, general condition and behavioral reactions, indices of enzymatic activity of detoxifying systems and morphological picture of peripheral blood. The obtained factual material convincingly demonstrates that drilling fluid has an adverse effect on adult guinea pigs. Lethal doses of drilling fluid (LD16, LD50, LD84, LD100) for a single intragastric administration, as well as indices of potential danger of acute poisoning are scientifically substantiated; The time of death and survival of experimental animals were calculated, which was dose-dependent. It was proven that the drilling fluid in an acute experiment leads to significant changes in the general condition of the experimental animals, accompanied by a decrease in food intake and water consumption, disruption of behavioral reactions and an emotional component. The dose dependence of the toxic effect of the drilling fluid was also established by the indicators of the dynamics of body weight gain, the activity of cytolytic enzymes, as well as the picture of peripheral blood. The features of the general toxic effect of the drilling fluid that we identified, with its acute single effect, indicate the systemic nature of the toxicity and danger of the drilling fluid.

Hearing loss is a major global health burden, and increasing evidence indicates that environmental and occupational exposure to neurotoxic metals may contribute to auditory dysfunction. This narrative review aimed to synthesize experimental evidence on metal-induced neuro-ototoxicity, with particular emphasis on morphological and functional alterations affecting peripheral and central components of the auditory system. A structured literature search was conducted in PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar, focusing on animal studies investigating lead, mercury, cadmium, arsenic, and chromium exposure and auditory outcomes. Experimental evidence demonstrates that these metals can induce cochlear hair-cell injury, particularly involving outer hair cells and basal cochlear regions, as well as ribbon synapse loss, spiral ganglion dysfunction, and alterations of the stria vascularis. Central auditory effects include disrupted neural conduction, altered auditory brainstem responses, glial activation, synaptic dysfunction, and changes within the cochlear nucleus and inferior colliculus. Across metals, oxidative and nitrative stress, mitochondrial dysfunction, neuroinflammation, calcium dysregulation, and regulated cell death emerge as interconnected mechanisms. Notably, auditory synaptopathy and central auditory dysfunction may occur with limited overt hair-cell loss. These findings support a multisite model of metal-induced neuro-ototoxicity and highlight the importance of evaluating both peripheral and central auditory pathways in experimental toxicology and environmental health research.