SARS-CoV-2 wastewater surveillance in the Czech Republic: Spatial and temporal differences in SARS-CoV-2 RNA concentrations and relationship to clinical data and wastewater parameters.

This study presents the results of systematic wastewater monitoring of SARS-CoV-2 RNA and basic wastewater parameters from four different wastewater treatment plants (WWTPs) in the Czech Republic over the 2020-2022 epidemic. Two-step reverse-transcription quantitative PCR targeting genes encoding the N and Nsp12 proteins was employed to detect SARS-CoV-2 RNA loading in 420 wastewater samples. The results obtained were used to evaluate the potential of wastewater analysis for describing the epidemiological situation in cities of different sizes and determining temporal differences based on the prevailing SARS-CoV-2 variant. Strong correlations between the number of active and hospitalised COVID-19 cases in each WWTP catchment area and the concentration of SARS-CoV-2 RNA detected in the wastewater clearly demonstrated the suitability of this wastewater-based epidemiological approach for WWTPs of different sizes and characteristics, despite differences in SARS-CoV-2 variant waves, with some WWTPs showing high predictive potential. This study demonstrated on the data from the Czech Republic that targeted systematic monitoring of wastewater provides sufficiently robust data for surveillance of viral loads in sample populations, and thus contributes to preventing the spread of infection and subsequent introduction of appropriate measures.

Titanium Dioxide Nanoparticles Modulate Systemic Immune Response and Increase Levels of Reduced Glutathione in Mice after Seven-Week Inhalation.

Titanium dioxide nanoparticles (TiO2 NPs) are used in a wide range of applications. Although inhalation of NPs is one of the most important toxicologically relevant routes, experimental studies on potential harmful effects of TiO2 NPs using a whole-body inhalation chamber model are rare. In this study, the profile of lymphocyte markers, functional immunoassays, and antioxidant defense markers were analyzed to evaluate the potential adverse effects of seven-week inhalation exposure to two different concentrations of TiO2 NPs (0.00167 and 0.1308 mg TiO2/m3) in mice. A dose-dependent effect of TiO2 NPs on innate immunity was evident in the form of stimulated phagocytic activity of monocytes in low-dose mice and suppressed secretory function of monocytes (IL-18) in high-dose animals. The effect of TiO2 NPs on adaptive immunity, manifested in the spleen by a decrease in the percentage of T-cells, a reduction in T-helper cells, and a dose-dependent decrease in lymphocyte cytokine production, may indicate immunosuppression in exposed mice. The dose-dependent increase in GSH concentration and GSH/GSSG ratio in whole blood demonstrated stimulated antioxidant defense against oxidative stress induced by TiO2 NP exposure.

E-cigarette use, opinion about harmfulness and addiction among university students in Bratislava, Slovakia.

OBJECTIVES: The study aimed to investigate the use of electronic cigarettes (EC) among medical students, their knowledge and beliefs (opinion about harmfulness and addiction potential) on ECs, perceptions of the risk, as well as to assess the type of education and cessation training they received during their study at Faculty of Medicine, Comenius University in Bratislava, Slovakia. METHODS: This cross-sectional, anonymous online e-mailed survey was conducted among medical students via the Study Department by sending e-mails containing the survey link. Participants completed the online questionnaire adapted from the American Survey on Tobacco and Alternative Tobacco Products. It included questions about the personal use of EC, perceptions about the harms and their role in disease causation, education and cessation training, and practices related to conventional cigarettes (CC), EC, and alternative tobacco products (ATP). The e-mailed questionnaire filled in 577 medical students (71.9% women) from Comenius University in Bratislava, the average age was 23 ± 2 years. The sample comprised 486 (84.2%) Slovak and 91 (15.8%) foreign students. The data were analysed using the Statistical Package for Social Science (SPSS) version 25. RESULTS: There were 385 (66.7%) non-smokers, 111 (19.3%) ex-smokers and 81 (14%) current smokers in the study sample. EC currently use 13.5% of medical students, with a statistically significant intersexual difference (22.2% males vs. 10.12% females; OR = 2.53, 95% CI: 1.55-4.13), more foreign students than Slovak students (24.2% vs. 11.52%; OR = 2.44, 95% CI: 1.41-4.26), more smokers of conventional cigarettes than non-smokers (46.9% vs. 8.06%; OR = 10.07, 95% CI: 5.85-17.34). EC seems to be less harmful to 59.97% of students, mostly in the age group ≤ 24 (61.76% vs. 51.49%; OR = 1.46, 95% CI: 1.03-2.07), 41.25% of students consider EC to be less addictive, 55.6% think they do not get enough education on EC during their medical study. CONCLUSION: The results overall show the high consumption of tobacco products and the lack of knowledge and awareness among medical students, future health care providers. In health promotion and disease prevention, they should serve as a model for their patients and for the general public as well. Our study emphasizes the need for intervention in this field at medical faculties and for support of further monitoring in Slovakia and other countries and draws attention to the ongoing lack of EC regulation.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation.

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×106 particles/cm3, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m3 continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3-CD19+ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

Effect of Humic Substances as Feed Additive on the Growth Performance, Antioxidant Status, and Health Condition of African Catfish (Clarias gariepinus, Burchell 1822).

In the present study, a possible nature immunostimulant and growth promoter-humic substances (HS) originating from Siberian leonardite mineraloid-were tested on juvenile Clarias gariepinus performance. Feed additive was applied onto commercial pelleted feed at four HS levels-0, 1, 3, and 6% w/w (HS0, HS1, HS3, HS6, respectively). Diets were tested in five repetitions (in total, n = 1800 individuals, mean body weight 28.1 ± 6.2 g) for 56 days. Growth and production parameters, fish condition and somatic indices, and overall mortality were evaluated after 14, 28, 42, and 56 days of exposure. Whereas, plasma samples were collected only after 0, 28, and 56 days, when fish health status was assessed with biochemical parameters (total proteins, TP; alanine aminotransferase, ALT; aspartate aminotransferase, AST; lactate dehydrogenase, LDH; cholesterol, CHOL; triglycerides, TAG) and fish antioxidant status with glutathione (reduced glutathione, GSH; oxidized glutathione, GSSG; glutathione ratio GSH/GSSG). Although a significantly positive effect of HS feed additive on growth performance was not found in the present study, moderately positive effects were found regarding biochemical parameters (ALT, AST, LDH, CHOL, and TAG) and antioxidants (GSH/GSSG ratio) that were improved especially in the HS3 group.

Fatty acids profile, atherogenic and thrombogenic indices in freshwater fish common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss) from market chain.

OBJECTIVE: The study examined the fatty acids composition and main nutrients composition in two freshwater fish species in the Czech Republic during one year. METHODS: Samples of common carp and rainbow trout were taken from a market chain during a year. All samples were homogenized and analyzed for lipid, protein, water, and ash contents. Energy value (E), sum of polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA), atherogenic index (AI) and thrombogenic index (TI) were then calculated. RESULTS: The freshwater fish on the Czech market chain have beneficial average value content of unsaturated fatty acids, Σ MUFA+PUFA in carp is 69.46% of all fatty acids, similar average value of Σ MUFA+PUFA - 70.83% is in rainbow trout. The calculated average value of AI in carp is 0.52 (SD = 0.06), AI in rainbow trout is 0.63 (SD = 0.07), the average TI in carp is 0.63 (SD = 0.09), TI in rainbow trout is 0.49 (SD = 0.05). CONCLUSION: Freshwater fish in the Czech market chain have beneficial value of PUFA, so AI and TI indices are low in both species of analysed fish. Regular consumption of fish meat is important in the prevention of cardiovascular diseases.

Occurrence of acrylamide in selected food products.

OBJECTIVE: Acrylamide is a toxic compound found in occupational and non-occupational environment. It originates from industrial use, technological processes in construction as well as food production, water purification, and laboratory use. Adverse effects including neurotoxicity, probably carcinogenicity, genotoxicity, teratogenicity, and reproductive toxicity were reported in many studies. Our study is focused on acrylamide content in selected food products in the Czech Republic. METHOD: In this study, we determined acrylamide content in selected samples of commonly consumed food products (potato chips, biscuits, popcorn, corn flakes, breakfast cereals, and baked muesli). RESULTS: The concentration of acrylamide in most samples of potato chips, biscuits and popcorn exceeded the benchmark limits. The acrylamide content in samples of potato chips from one manufacturer in 4 cases out of 5 analysed samples exceeded benchmark limit. On the other hand, no corn flakes sample acrylamide content from the same manufacture exceeded the benchmark limit. With 20 of all analysed samples exceeding the benchmark levels for acrylamide, it can be concluded that 47.6% of samples did not comply with the benchmark level. CONCLUSION: Dietary intake of frequently consumed food products with the acrylamide content exceeding the recommended comparative value could have adverse effects on the human health. Our study confirmed high amount of acrylamide in some selected food samples. The reduction of dietary burden with acrylamide is possible by complying with the correct technological principles in food preparation.

Assessment of local muscular load of dental practitioners.

OBJECTIVE: Hands and forearms are one of the most common localisations of musculoskeletal disorders (MSDs) among dental practitioners. The aim of this study was to objectively assess the local muscular load of hands and forearms of dental practitioners during various treatment procedures using the method of the integrated electromyography (iEMG). This method is used for health risk assessment and categorization of working operation within the official national methodology. METHODS: A total of 24 measurements were performed on 10 dental practitioners during 8 different dental treatments; mostly on those which are most frequent in clinical practice, i.e. endodontic treatment, tooth extraction, tooth restoration with filling and prosthetic treatment. The EMG Holter was used to detect the electromyographic potentials determining the local muscular load. RESULTS: All the muscle groups of the forearm were relatively evenly loaded at work. During the dynamic work activity, the average time-weighted value of maximum voluntary contraction (%MVC) was in the range from 1 to 30 %MVC for all evaluated muscle groups. The mean average time-weighted value of %MVC did not exceed 6% (a critical limit of the mean average time-weighted value of %MVC) in any of the evaluated muscle groups. The results of the frequency analysis showed that large (55-70 %MVC) and rarely the limits exceeding values (above 70 %MVC) were observed for individual muscle groups. These forces are related to performing tasks at inaccessible locations associated with non-physiological working positions. The differences in the mean forearm muscle load between the upper limbs were statistically significant in total (p < 0.001), for flexors (p = 0.017) and for extensors (p = 0.006). CONCLUSION: In view of the results of this study, the work of dentists can be ranked in category 2 in terms of the local muscle load factor according to the currently valid legislation in the Czech Republic.

Risk of exposure to acrylamide.

OBJECTIVES: Acrylamide is a toxic compound that can be found it both occupational and non-occupational environments. This study focuses on its sources and health effects of its exposure. METHODS: Adverse effects of acrylamide, especially carcinogenic, genotoxic, and teratogenic were reported in many studies conducted on animals. Neurotoxicity was reported in workers exposed to acrylamide in the occupational environment. Another important source of populations' exposure to acrylamide is their nutrition. RESULTS: This study focuses on humans' exposure to acrylamide from various sources and its harmful effects on their health. CONCLUSIONS: Dietary intake of acrylamide, as well as occupational exposure, cigarette smoking, cosmetics usage and other environmental sources could have a significant effect on human health.

Exposure to mercury from dental amalgam: actual contribution for risk assessment.

OBJECTIVE: Mercury dental amalgam restorations are an important source of chronic exposure to mercury in the whole population and special attention should be paid not only to occupational exposure to mercury during the preparation and administration of amalgam. The authors' report is an up-to-date contribution to the health risk assessment of mercury use in dentistry, namely occupational exposure to mercury in dentists working with dental amalgam and exposure to mercury in persons treated with amalgam dental restorations. METHODS: Determination of total mercury in samples of biological material (urine, hair) was performed during 2017 and 2018 in 50 persons by the AAS method using the mercury vapour generation technique at 254.6 nm. RESULTS: Current dental exposures based on the most recent findings do not exceed acceptable risk levels and are below the biological limit of mercury in urine valid for occupationally exposed persons (100 µg.g-1 of creatinine), namely median value was 1.48 (min. < limit of detection (LOD), max. 17.14) µg.g-1 of creatinine (40 persons), total mercury content in hair of dental personnel expressed as median value was 0.340 (min. 0.060, max.1.628) µg.g-1. In controls (10 persons) was total mercury content in urine expressed as median value 0.36 (min. < LOD, max. 2.74) µg.g-1 of creatinine, in hair was median value 0.224 (min. 0.059, max. 0.453) µg.g-1. CONCLUSIONS: Authors support opinion that amalgam fillings in the oral cavity are a permanent source of mercury for the body itself.

Six-week inhalation of CdO nanoparticles in mice: The effects on immune response, oxidative stress, antioxidative defense, fibrotic response, and bones.

Due to the growing number of applications of cadmium oxide nanoparticles (CdO NPs), there is a concern about their potential deleterious effects. The objective of our study was to investigate the effect of CdO NPs on the immune response, renal and intestine oxidative stress, blood antioxidant defence, renal fibrotic response, bone density and mineral content. Six-week-old female ICR mice were exposed to CdO NPs for 6 weeks by inhalation (particle size: 9.82 nm, mass concentration: 31.7 µg CdO/m3, total deposited dose: 0.195 µg CdO/g body weight). CdO NPs increased percentage of thymus CD3e+CD8a+ cells and moderately enhanced splenocyte proliferation and production of cytokines and chemokines. CdO NPs elevated pro-fibrotic factors (TGF-ß2, α-SMA and collagen I) in the kidney, and concentrations of AGEs in the intestine. The ratio of GSH and GSSG in blood was slightly reduced. Exposure to CdO NPs resulted in 10-fold higher Cd concentration in tibia bones. No differences were found in bone mass density, mineral content, bone area values, bone concentrations of Ca, P, Mg and Ca/P ratio. Our findings indicate stimulation of immune/inflammatory response, oxidative stress in the intestine, starting fibrotic response in kidneys and accumulation of CdO NPs in bones of mice.