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Human neutrophil elastase (HNE) plays a pivotal role in innate immunity, inflammation, and tissue remodeling. Aberrant proteolytic activity of HNE contributes to organ destruction in various chronic inflammatory diseases including emphysema, asthma, and cystic fibrosis. Therefore, elastase inhibitors could alleviate the progression of these disorders. Here, we used the systematic evolution of ligands by exponential enrichment to develop ssDNA aptamers that specifically target HNE. We determined the specificity of the designed inhibitors and their inhibitory efficacy against HNE using biochemical and in vitro methods, including an assay of neutrophil activity. Our aptamers inhibit the elastinolytic activity of HNE with nanomolar potency and are highly specific for HNE and do not target other tested human proteases. As such, this study provides lead compounds suitable for the evaluation of their tissue-protective potential in animal models.
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Aptâmeros de Nucleotídeos , Elastase de Leucócito , Inibidores de Serina Proteinase , Humanos , Fibrose Cística/tratamento farmacológico , Enfisema/tratamento farmacológico , Elastase de Leucócito/antagonistas & inibidores , Neutrófilos/efeitos dos fármacos , Inibidores de Serina Proteinase/síntese química , Inibidores de Serina Proteinase/farmacologia , Inibidores de Serina Proteinase/uso terapêutico , Aptâmeros de Nucleotídeos/síntese química , Aptâmeros de Nucleotídeos/farmacologia , Aptâmeros de Nucleotídeos/uso terapêutico , Sensibilidade e Especificidade , Ativação Enzimática/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Células CultivadasRESUMO
BACKGROUND: The real-world consequences of a Philips/Respironics recall for positive airway pressure (PAP) devices distributed between 2009 and 2021 are unknown. METHODS: We conducted a retrospective population-based study using health administrative databases (Ontario, Canada) on all new adult PAP users identified through the provincial funding system, free of cancer at baseline, who initiated (claimed) PAP treatment between 2012 and 2018. Everyone was followed from the PAP claim date to the earliest of incident cancer diagnosis, death, or the end of the follow-up (March 2022). We used inverse probability of treatment weighting to balance baseline characteristics between individuals on recalled devices and those on devices from other manufacturers. Weighted hazard ratios of incident cancer were compared between groups. RESULTS: Of 231 692 individuals identified, 58 204 (25.1%) claimed recalled devices, and 173 488 (74.9%) from other manufacturers. A meaningful baseline difference between groups (standardised difference≥0.10) was noted only by location-relevant covariates; other variables were mostly equally distributed (standardised differences≤0.06). Over a median follow-up of 6.3â years (IQR: 4.9-8.0), 11 166 (4.8%) developed cancer: unadjusted rates per 10 000 Person-Year (95 CI%) of 78.8 (76.0-81.7) in the recall group versus74.0 (72.4-75.6) in others (p=0.0034). Propensity score weighting achieved excellent balance in baseline characteristics between groups (standardised differences≤0.07). On a weighted sample, there was no statistical difference in the hazard of incident cancer between groups: cause-specific hazard ratio (recalled versus others) of 0.97, 95% CI: 0.89-1.06. CONCLUSION: In our real-world population study, compared to other manufacturers and adjusting for confounders, recalled devices do not appear to be independently associated with developing cancer.
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OBJECTIVE: Studies suggest rheumatoid arthritis (RA) patients could benefit from periodontal treatment. However, published data are inconsistent, and there is a need for better-controlled research. Our study aims to address these limitations. METHODS: In this exploratory randomised delayed-start study, 22 RA patients with moderate/severe periodontitis were subjected to full-mouth debridement. Periodontal and rheumatological assessments, including measuring anti-cyclic citrullinated peptide 2 (CCP2) IgG levels, were performed at baseline (V1), 2 months (V2) and 6 months (V3) after step 1 and 2 of periodontal therapy. Primary outcome was changes in disease activity score for 28 joints (DAS28) between V2 and V1. Secondary outcomes were changes in other rheumatological or periodontal clinical parameters (V2 or V3-V1). RESULTS: RA disease activity was significantly higher in RA patients with severe periodontitis compared to moderate periodontitis at baseline, with significant positive correlations between several rheumatological and periodontal parameters. After periodontal treatment, RA patients with severe, but not moderate, periodontitis demonstrated significant improvements in DAS28 (ΔV2-V1, p = 0.042; ΔV3-V1, p = 0.001) and significant reduction in anti-CCP2 IgG levels at V3 (p = 0.032). CONCLUSION: Periodontal treatment is locally effective in patients with RA and impacts RA disease activity and anti-CCP2 antibody levels in patients with severe periodontitis. Hence, our data suggest that periodontal assessment and treatment should be integrated in the management of RA patients within a treat-to-target strategy. CLINICAL TRIAL REGISTRATION: www.isrctn.com, ISRCTN 17950307.
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Recent studies have revealed the role of endogenous hydrogen sulfide (H2S) in the development of breast cancer. The capacity of cells to generate H2S and the activity and expression of the main enzymes (cystathionine beta synthase; CBS, cystathionase γ-lyase; CGL, 3-mercaptopyruvate sulfurtransferase; MPST and thiosulfate sulfurtransferase; TST) involved in H2S metabolism were analyzed using an in vitro model of a non-tumourigenic breast cell line (MCF-12A) and a human breast adenocarcinoma cell line (MCF-7). In both cell lines, MPST, CGL, and TST expression was confirmed at the mRNA (RT-PCR) and the protein (Western Blot) level, while CBS expression was detected only in MCF-7 cells. Elevated levels of GSH, sulfane sulfur and increased CBS and TST activity were presented in the MCF-7 compared to the MCF-12A cells. It appears that cysteine might be mainly a substrate for GSH synthesis in breast adenocarcinoma. Increased capacity of the cells to generate H2S was shown for MCF-12A compared to MCF-7 cell line. Results suggest an important function of CBS in H2S metabolism in breast adenocarcinoma. The presented work may contribute to further research on new therapeutic possibilities for breast cancer - one of the most frequently diagnosed types of cancer among women.
Assuntos
Adenocarcinoma , Neoplasias da Mama , Sulfeto de Hidrogênio , Humanos , Feminino , Células MCF-7 , Sulfeto de Hidrogênio/metabolismo , Cistationina beta-Sintase/metabolismoRESUMO
The aims of this study were to determine whether it is possible to use peptide microarrays obtained using the SPOT technique (immobilized on cellulose) and specific polyclonal antibodies to select fragments that reconstruct the outer sphere of proteins and to ascertain whether the selected peptide fragments can be useful in the study of their protein-protein and/or peptide-protein interactions. Using this approach, epidermal growth factor (EGF) fragments responsible for the interaction with the EGF receptor were searched. A library of EGF fragments immobilized on cellulose was obtained using triazine condensing reagents. Experiments on the interactions with EGFR confirmed the high affinity of the selected peptide fragments. Biological tests on cells showed the lack of cytotoxicity of the EGF fragments. Selected EGF fragments can be used in various areas of medicine.
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Fator de Crescimento Epidérmico , Peptídeos , Anticorpos , Celulose , Fator de Crescimento Epidérmico/farmacologia , Fator de Crescimento Epidérmico/metabolismo , Fragmentos de Peptídeos/metabolismo , Receptores ErbB/metabolismoRESUMO
Obstructive sleep apnea has been associated with cognitive impairment and may be linked to disorders of cognitive function. These associations may be a result of intermittent hypoxaemia, sleep fragmentation and changes in sleep microstructure in obstructive sleep apnea. Current clinical metrics of obstructive sleep apnea, such as the apnea-hypopnea index, are poor predictors of cognitive outcomes in obstructive sleep apnea. Sleep microstructure features, which can be identified on sleep electroencephalography of traditional overnight polysomnography, are increasingly being characterized in obstructive sleep apnea and may better predict cognitive outcomes. Here, we summarize the literature on several major sleep electroencephalography features (slow-wave activity, sleep spindles, K-complexes, cyclic alternating patterns, rapid eye movement sleep quantitative electroencephalography, odds ratio product) identified in obstructive sleep apnea. We will review the associations between these sleep electroencephalography features and cognition in obstructive sleep apnea, and examine how treatment of obstructive sleep apnea affects these associations. Lastly, evolving technologies in sleep electroencephalography analyses will also be discussed (e.g. high-density electroencephalography, machine learning) as potential predictors of cognitive function in obstructive sleep apnea.
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Apneia Obstrutiva do Sono , Sono , Humanos , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/diagnóstico , Cognição , Eletroencefalografia , BiomarcadoresRESUMO
BACKGROUND: Bleeding diatheses, common among patients with ESKD, can lead to serious complications, particularly during invasive procedures. Chronic urea overload significantly increases cyanate concentrations in patients with ESKD, leading to carbamylation, an irreversible modification of proteins and peptides. METHODS: To investigate carbamylation as a potential mechanistic link between uremia and platelet dysfunction in ESKD, we used liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to quantify total homocitrulline, and biotin-conjugated phenylglyoxal labeling and Western blot to detect carbamylated integrin α IIb ß 3 (a receptor required for platelet aggregation). Flow cytometry was used to study activation of isolated platelets and platelet-rich plasma. In a transient transfection system, we tested activity and fibrinogen binding of different mutated forms of the receptor. We assessed platelet adhesion and aggregation in microplate assays. RESULTS: Carbamylation inhibited platelet activation, adhesion, and aggregation. Patients on hemodialysis exhibited significantly reduced activation of α IIb ß 3 compared with healthy controls. We found significant carbamylation of both subunits of α IIb ß 3 on platelets from patients receiving hemodialysis versus only minor modification in controls. In the transient transfection system, modification of lysine 185 in the ß 3 subunit was associated with loss of receptor activity and fibrinogen binding. Supplementation of free amino acids, which was shown to protect plasma proteins from carbamylation-induced damage in patients on hemodialysis, prevented loss of α IIb ß 3 activity in vitro. CONCLUSIONS: Carbamylation of α IIb ß 3-specifically modification of the K185 residue-might represent a mechanistic link between uremia and dysfunctional primary hemostasis in patients on hemodialysis. The observation that free amino acids prevented the carbamylation-induced loss of α IIb ß 3 activity suggests amino acid administration during dialysis may help to normalize platelet function.
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Complexo Glicoproteico GPIIb-IIIa de Plaquetas , Uremia , Humanos , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/química , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/genética , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Carbamilação de Proteínas , Espectrometria de Massas em Tandem , Plaquetas , Uremia/complicações , Uremia/metabolismo , Fibrinogênio/química , Fibrinogênio/metabolismo , AminoácidosRESUMO
Bladder cancer is a common malignancy associated with high recurrence rates and potential progression to invasive forms. Sorafenib, a multi-targeted tyrosine kinase inhibitor, has shown promise in anti-cancer therapy, but its cytotoxicity to normal cells and aggregation in solution limits its clinical application. To address these challenges, we investigated the formation of supramolecular aggregates of sorafenib with Congo red (CR), a bis-azo dye known for its supramolecular interaction. We analyzed different mole ratios of CR-sorafenib aggregates and evaluated their effects on bladder cancer cells of varying levels of malignancy. In addition, we also evaluated the effect of the test compounds on normal uroepithelial cells. Our results demonstrated that sorafenib inhibits the proliferation of bladder cancer cells and induces apoptosis in a dose-dependent manner. However, high concentrations of sorafenib also showed cytotoxicity to normal uroepithelial cells. In contrast, the CR-BAY aggregates exhibited reduced cytotoxicity to normal cells while maintaining anti-cancer activity. The aggregates inhibited cancer cell migration and invasion, suggesting their potential for metastasis prevention. Dynamic light scattering and UV-VIS measurements confirmed the formation of stable co-aggregates with distinctive spectral properties. These CR-sorafenib aggregates may provide a promising approach to targeted therapy with reduced cytotoxicity and improved stability for drug delivery in bladder cancer treatment. This work shows that the drug-excipient aggregates proposed and described so far, as Congo red-sorafenib, can be a real step forward in anti-cancer therapies.
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Vermelho Congo , Neoplasias da Bexiga Urinária , Humanos , Sorafenibe/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Neoplasias da Bexiga Urinária/tratamento farmacológicoRESUMO
Yohimbine is a small indole alkaloid derived from the bark of the yohimbe tree with documented biological activity, including anti-inflammatory, erectile dysfunction relieving, and fat-burning properties. Hydrogen sulfide (H2S) and sulfane sulfur-containing compounds are regarded as important molecules in redox regulation and are involved in many physiological processes. Recently, their role in the pathophysiology of obesity and obesity-induced liver injury was also reported. The aim of the present study was to verify whether the mechanism of biological activity of yohimbine is related to reactive sulfur species formed during cysteine catabolism. We tested the effect of yohimbine at doses of 2 and 5 mg/kg/day administered for 30 days on aerobic and anaerobic catabolism of cysteine and oxidative processes in the liver of high-fat diet (HFD)-induced obese rats. Our study revealed that HFD resulted in a decrease in cysteine and sulfane sulfur levels in the liver, while sulfates were elevated. In the liver of obese rats, rhodanese expression was diminished while lipid peroxidation increased. Yohimbine did not influence sulfane sulfur and thiol levels in the liver of obese rats, however, this alkaloid at a dose of 5 mg decreased sulfates to the control level and induced expression of rhodanese. Moreover, it diminished hepatic lipid peroxidation. It can be concluded that HFD attenuates anaerobic and enhances aerobic cysteine catabolism and induces lipid peroxidation in the rat liver. Yohimbine at a dose of 5 mg/kg can alleviate oxidative stress and reduce elevated concentrations of sulfate probably by the induction of TST expression.
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Cisteína , Tiossulfato Sulfurtransferase , Masculino , Ratos , Animais , Cisteína/metabolismo , Tiossulfato Sulfurtransferase/metabolismo , Tiossulfato Sulfurtransferase/farmacologia , Ioimbina , Dieta Hiperlipídica , Estresse Oxidativo , Enxofre/metabolismo , Fígado , Compostos de Enxofre/farmacologia , Obesidade/metabolismoRESUMO
OBJECTIVE: The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) treatment on the Fatigue Severity Scale (FSS, preplanned primary outcome), another fatigue measure, sleep quality, somnolence, pain, disability, and quality of life in multiple sclerosis (MS) patients with obstructive sleep apnea-hypopnea (OSAH). METHODS: In a randomized, double-blind trial (NCT01746342), MS patients with fatigue, poor subjective sleep quality, and OSAH (apnea-hypopnea index of ⩾ 15 events per hour/sleep), but without severe OSAH (apnea-hypopnea index > 30, and 4% oxygen desaturation index > 15 events/hour or severe somnolence), were randomized to fixed CPAP or sham CPAP for 6 months. Outcome assessments were performed at 3 and 6 months. RESULTS: Of 49 randomized patients, 34 completed the protocol. Among completers, FSS did not improve with CPAP compared to sham at 6 months. FSS tended to improve (p = 0.09), and sleepiness (Epworth Sleepiness Scale) improved significantly (p = 0.03) at 3 months with CPAP compared to sham, but there were no other improvements with CPAP at either study evaluation. CONCLUSION: In non-severe OSAH patients, CPAP did not significantly improve the primary outcome of FSS change at 6 months. In secondary analyses, we found a trend to improved FSS, and a significant reduction in somnolence with CPAP at 3 months.
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Esclerose Múltipla , Apneia Obstrutiva do Sono , Pressão Positiva Contínua nas Vias Aéreas , Humanos , Esclerose Múltipla/complicações , Esclerose Múltipla/terapia , Qualidade de Vida , Apneia Obstrutiva do Sono/terapia , Qualidade do Sono , Resultado do TratamentoRESUMO
Although the theory of density evolution in maps and ordinary differential equations is well developed, the situation is far from satisfactory in continuous time systems with delay. This paper reviews some of the work that has been done numerically, the interesting dynamics that have emerged, and the largely unsuccessful attempts that have been made to analytically treat the evolution of densities in differential delay equations. We also present a new approach to the problem and illustrate it with a simple example.
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Lavandula angustifolia, one of the most popular medicinal plants, is the source of a bioactive essential oil characterized by a wide spectrum of biological activity, e.g., antiseptic, analgesic, and anticancer effects. In dermatology, the oil helps to relieve skin inflammation and exhibit wound healing potential. However, the mechanism of action of the lavender oil depends on its composition, which in turn is dependent on the origin and growing conditions. Our study aimed to compare the composition and proregenerative properties of the commercially-available narrow-leaved lavender oil produced in Provence, France, with the oil obtained from the narrow-leaved lavender cultivated locally in Poland. GC/MS analysis showed that self-manufactured essential oil had lower linalool content than commercial oil (23.2 vs. 40.2%), comparable linalyl acetate content (40.6 vs. 44%), while the proportion of lavandulyl acetate was significantly higher (23.2 vs. 5.5%). To determine the influence of lavender oil on the production of proinflammatory cytokines and proregenerative growth factors, gene expression of the selected signaling molecules by HaCaT cells was investigated using real-time PCR. Results showed a concentration-dependent effect of lavender oils on the production of IL-6, IL-8, and VEGF by the keratinocyte cell line. Finally, the potential of the lavender oil to increase the production of VEGF, the most important angiogenic factor, with the in-house preparation performing significantly better in the in vitro cell models was identified.
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Lavandula/química , Óleos Voláteis/química , Linhagem Celular Tumoral , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Óleos Voláteis/farmacologia , Cicatrização/efeitos dos fármacosRESUMO
Small studies have suggested that patients with chronic obstructive pulmonary disease (COPD) have poor sleep quality. Our aim was to examine the prevalence of subjective sleep-related complaints and predictors of poor sleep quality in a large community-based COPD cohort. We analyzed cross-sectional data on sleep questionnaire responses from the Canadian Cohort of Obstructive Lung Disease (CanCOLD) study, a population-based, prospective longitudinal cohort study across Canada. The cohort comprises a COPD group and two matched non-COPD (never-smokers and ever-smokers) groups. Sleep-related symptoms were assessed using questionnaires including Pittsburgh Sleep Quality Index (PSQI). A total score of PSQI > 5 is indicative of poor sleep quality. Health-related quality of life measures and the presence of mood disturbance were assessed using Short Form-36™ Health Survey (SF-36) multi-item questionnaires and Hospital Anxiety and Depression Scale (HADS), respectively. Predictors of poor sleep quality were analyzed using multivariable logistic regression analysis. Of the 1123 subjects, 263 were healthy controls, 323 at-risk controls, and 537 had COPD (297 had mild, 240 with moderate to severe disease). The mean PSQI score was not significantly different between groups. COPD patients with poor sleep quality had lower diffusion capacity, higher HADS anxiety and depression scores and lower SF-36 mental and physical component summary scores than COPD patients classified as good sleepers. The presence of restless legs and obstructive sleep apnea symptoms, waist circumference, predicted diffusion capacity and HADS anxiety and depression scores were identified as independent predictors of poor sleep quality.
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Ansiedade/epidemiologia , Depressão/epidemiologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Síndrome das Pernas Inquietas/epidemiologia , Apneia Obstrutiva do Sono/epidemiologia , Transtornos do Sono-Vigília/epidemiologia , Idoso , Ansiedade/psicologia , Canadá/epidemiologia , Estudos de Coortes , Depressão/psicologia , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prevalência , Capacidade de Difusão Pulmonar , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Doença Pulmonar Obstrutiva Crônica/psicologia , Fatores de Risco , Índice de Gravidade de Doença , Sono , Transtornos do Sono-Vigília/fisiopatologia , Transtornos do Sono-Vigília/psicologia , Inquéritos e Questionários , Circunferência da CinturaRESUMO
The aim of the study was the assessment of the ability of short peptides to form aggregates under physiological conditions. The dipeptides studied were derived from different aromatic amino acids (heteroaromatic peptides). Tripeptides were obtained from two distinct aromatic amino acids and cysteine or methionine residue in the C-terminal, N-terminal, or central position. The ability of the peptides to form fibrous aggregates under physiological conditions was evaluated using three independent methods: the Congo Red assay, the Thioflavin T assay, and microscopic examinations using normal and polarized light. Materials potentially useful for regenerative medicine were selected based on their cytotoxicity to the endothelial cell line EA.hy 926 and physicochemical properties of films formed by peptides. The required parameters of biocompatibility were fulfilled by H-PheCysTrp-OH, H-PheCysTyr-OH, H-PheTyrMet-OH, and H-TrpTyr-OH.
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Aminoácidos Aromáticos/química , Peptídeos/química , Aminoácidos Aromáticos/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Humanos , Espectroscopia de Ressonância Magnética , Peptídeos/síntese química , Peptídeos/farmacologia , Agregados Proteicos , Técnicas de Síntese em Fase SólidaRESUMO
Citrullination, a posttranslational modification, is catalyzed by peptidylarginine deiminases (PADs), a unique family of enzymes that converts peptidyl-arginine to peptidyl-citrulline. Overexpression and/or increased PAD activity is observed in rheumatoid arthritis (RA), Alzheimer's disease, multiple sclerosis, and cancer. Moreover, bacterial PADs, such as Porphyromonas gingivalis PAD (PPAD), may have a role in the pathogenesis of RA, indicating PADs as promising therapeutic targets. Herein, six novel compounds were examined as potential inhibitors of human PAD4 and PPAD, and compared to an irreversible PAD inhibitor, Cl-amidine. Four of the tested compounds (compounds 2, 3, 4, and 6) exhibited a micromolar-range inhibition potency against PAD4 and no effect against PPAD in the in vitro assays. Compound 4 was able to inhibit the PAD4-induced citrullination of H3 histone with higher efficiency than Cl-amidine. In conclusion, compound 4 was highly effective and presents a promising direction in the search for novel RA treatment strategies.
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Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Porphyromonas gingivalis/enzimologia , Desiminases de Arginina em Proteínas/antagonistas & inibidores , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/microbiologia , Citrulinação/efeitos dos fármacos , Descoberta de Drogas , Histonas/metabolismo , Humanos , Proteína-Arginina Desiminase do Tipo 4 , Desiminases de Arginina em Proteínas/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologiaRESUMO
This study investigates the propensity of short peptides to self-organize and the influence of aggregates on cell cultures. The dipeptides were derived from both enantiomers of identical aromatic amino acids and tripeptides were prepared from two identical aromatic amino acids with one cysteine or methionine residue in the C-terminal, N-terminal, or central position. The formation or absence of fibrous structures under physiological conditions was established using Congo Red and Thioflavine T assays as well as by microscopic examination using normal and polarized light. The in vitro stability of the aggregates in buffered saline solution was assessed over 30 days. Materials with potential for use in regenerative medicine were selected based on the cytotoxicity of the peptides to the endothelial cell line EA.hy 926 and the wettability of the surfaces of the films, as well as using scanning electron microscopy. The criteria were fulfilled by H-dPhedPhe-OH, H-dCysdPhedPhe-OH, H-CysTyrTyr-OH, H-dPhedPhedCys-OH, H-TyrTyrMet-OH, and H-TyrMetTyr-OH. Our preliminary results suggest that the morphology and cell viability of L919 fibroblast cells do not depend on the stereochemistry of the self-organizing peptides.
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Aminoácidos/química , Dipeptídeos/química , Oligopeptídeos/química , Alicerces Teciduais , Animais , Benzotiazóis , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Vermelho Congo , Dipeptídeos/farmacologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Camundongos , Oligopeptídeos/farmacologia , Agregados Proteicos , Medicina Regenerativa , Tiazóis , Engenharia TecidualRESUMO
The aim of this work was to assess dietary risk resulting from consumption of polycyclic aromatic hydrocarbons (PAHs) with tea infusions. To this end, levels of 28 PAHs in black, green, red and white teas available on the Polish retail market have been assessed. Profiles and correlation between concentrations of individual PAHs have been identified. A model study on transfer of PAHs from tea leaves into tea preparations has been conducted. Relatively high concentrations of 28 evaluated PAHs have been found in 58 tested samples of black, green, red and white teas sampled on the Polish retail market. Total concentration ∑28PAH ranged from 57 to 696 µg kg-1 with mean 258 µg kg-1 (dry tea leaves). The most mature tea leaves fermented to a small degree contained relatively the highest PAH levels among all four tested tea types. Relatively low PAH transfer rates into tea infusions and limited volumes of the consumed tea keep the risks associated with PAH dietary intake at a safely low level. The worst-case scenario dietary intake values were 7.62/0.82/0.097 ng kg-1 b.w. day-1 (estimated on the basis of the maximum found concentrations 696/113/23 µg kg-1 and maximum observed transfer rates 24/16/9%) for ∑28PAH/∑PAH4/B[a]P, respectively. MOE values calculated using the above worst case estimates exceeded 700,000 and 400,000 (BMDL10 0.07 and 0.34 mg kg-1 b.w. day-1) for B[a]P and PAH4, respectively. Both B[a]P and PAH4 concentrations may be used as indicators of total PAH concentration in tea leaves; PAH4 slightly better fits low molecular weight PAHs. Several correlations between various PAHs/groups of PAHs have been identified, the strongest one (R2 = 0.92) between PAH4 and EU PAH 15+1.
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Contaminação de Alimentos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Medição de Risco/métodos , Chá/química , Benzo(a)pireno/análise , Exposição Ambiental/análise , Humanos , Folhas de Planta/química , PolôniaRESUMO
Persistent organic pollutants (POPs) are known to show endocrine disrupting (ED) activity, including interactions with hormone receptors. The aim of this work was to develop a bioassay applicable for evaluation of ED potency of highly lipophilic metabolites of POPs. To that end, a yeast-based bio-assay protocol was used. Estrogenic / androgenic activity of some native brominated biphenyl ethers (BDEs) / chlorinated biphenyls (CBs), and their hydroxylated / methoxylated metabolites was assessed. Since data (including potency compared to reference native hormones) obtained using different protocols vary, the possibility that yeast transforms POPs into some more potent compounds was first checked; it seems that no such transformation is important from the test applicability standpoint. The developed method was sensitive with EC50 values 6.5*10-11 M and 4.5*10-9 M calculated for E2 and DHT, respectively. Both CBs and BDEs show weak estrogenic activity negatively correlated with the degree of their halogenation, but their metabolites are significantly more potent xenohormones. 4-OH-2,2',4',6'-TeCB was the most potent estrogen receptor (ER) agonist among all tested compounds; its activity was only 1,000 times lower than that of native E2.