Associations between urinary biomarkers of oxidative stress and biomarkers of tobacco smoke exposure in smokers.

Oxidative stress can contribute to the development of diseases, and may originate from exposures to toxicants commonly found in air pollution and cigarette smoke such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Yet, associations between these exposures and oxidative stress biomarkers are poorly characterized. We report here novel associations between 14 exposure biomarkers of PAHs and VOCs, and two oxidative stress biomarkers; 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-isoprostaglandin F2α (8-isoprostane) in urine obtained from smokers participating in an ongoing clinical study (ESTxENDS, NCT03589989). We also assessed associations between six biomarkers of tobacco smoke exposure (metabolites of nicotine and tobacco-specific nitrosamines (TSNAs)) and both oxidative stress biomarkers. We then quantified the relative importance of each family of the 20 exposure biomarkers on oxidative stress. Participating smokers (153 men and 117 women, median age 44 years) had on average smoked 25 [2-62] years and smoked about 17 [5-40] cigarettes per day at the time of the study. Multiple linear regression results showed an association between 8-oxodG concentrations and the following metabolites in decreasing relative importance: PAHs (beta coefficient ß = 0.105, p-value <0.001, partial R2 = 0.15) > VOCs (ß = 0.028, p < 0.001, partial R2 = 0.09) > nicotine (ß = 0.226, p < 0.001, partial R2 = 0.08); and between 8-isoprostane concentrations and metabolites of PAHs (ß = 0.117, p < 0.001, partial R2 = 0.14) > VOCs (ß = 0.040, p < 0.001, partial R2 = 0.14) > TSNAs (ß = 0.202, p = 0.003, partial R2 = 0.09) > nicotine (ß = 0.266, p < 0.001, partial R2 = 0.08). Behavioral factors known to contribute to oxidative stress, including sleep quality, physical activity, and alcohol consumption, did not play a significant role. Exposures to PAHs and VOCs among smokers were significantly associated with oxidative stress.

Adsorption of progesterone onto microplastics and its desorption in simulated gastric and intestinal fluids.

The sorption of hydrophobic organic compounds (HOC) onto microplastics is relatively well reported in the literature, while their desorption remains poorly investigated, especially in biological fluids. The present study investigated the sorption and desorption of progesterone on polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics. The sorption experiments showed that the equilibrium was reached in a few hours for all plastics. A sorption efficiency of 357.1 µg g-1 was found for PE and PS, and 322.6 µg g-1 for PP. Sorption experiments indicated that adsorption would certainly happen via surface sorption and a potentially pore-filling mechanism. The desorption was carried out in Simulated Gastric Fluid (SGF) and Simulated Intestinal Fluid (SIF), whose formulations were more complex than similar models reported so far. It has been found that the desorption was higher in SIF as compared to SGF, due to micelle formation in SIF promoting the pollutant solubilization. The sorption of pepsin onto microplastics has also been revealed, suggesting a competition between pollutants and pepsin for sorption sites and a potent reduction in pollutant solubilization. This study indicates that the ingestion of microplastics could be considered as an additional route of exposure to pollutants and therefore emphasizes pollutant bioavailability for aquatic organisms.

Occurrence of organic micropollutants and human health risk assessment based on consumption of Amaranthus viridis, Kinshasa in the Democratic Republic of the Congo.

The contamination of water resource and food chain by persistent organic pollutants (POPs) constitutes a major environmental and human health concern worldwide. The aim of this study was to investigate the levels of POPs in irrigation water, soil and in Amaranthus viridis (A. viridis) from different gardening sites in Kinshasa to evaluate the potential environmental and human health risks. A survey study for the use of pesticides and fertilizers was carried out with 740 market gardeners. The levels of POPs (including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs)) were analyzed in irrigation water and 144 vegetable samples collected from different gardening sites. The assessment of potential human health risk was estimated by calculating daily intake and toxic equivalency to quantify the carcinogenicity. The results show highest PAH levels in A. viridis from all studied sites. The concentrations of the sum of seven PCBs (Σ7PCBS) congeners in analyzed plants ranged between 15.89 and 401.36 ng g-1. The distributions of OCPs in both water and A. viridis were congener specific, chlorpyrifos-ethyl and p,p'-DDE were predominantly detected. Among PBDEs, only BDE47 was quantified with noticeable concentration in A. viridis, while no PBDEs were detected in irrigation water. Higher estimated daily intake values indicate that consuming leafy vegetables might associate with increased human health risks. However, calculated incremental lifetime cancer risk values indicates no potential carcinogenic risk for the local population. The results of this study provide important information on A. viridis contamination by POPs and strongly recommend implementing the appropriate measures to control the use of chemicals used in studied gardening areas. Thus in Kinshasa, urban agriculture control programs for POPs and fertilizers is very important in order to protect the public health through direct and dietary exposure pathways.

Can the detection dog alert on COVID-19 positive persons by sniffing axillary sweat samples? A proof-of-concept study.

The aim of this proof-of-concept study was to evaluate if trained dogs could discriminate between sweat samples from symptomatic COVID-19 positive individuals (SARS-CoV-2 PCR positive) and those from asymptomatic COVID-19 negative individuals. The study was conducted at 2 sites (Paris, France, and Beirut, Lebanon), followed the same training and testing protocols, and involved six detection dogs (three explosive detection dogs, one search and rescue dog, and two colon cancer detection dogs). A total of 177 individuals were recruited for the study (95 symptomatic COVID-19 positive and 82 asymptomatic COVID-19 negative individuals) from five hospitals, and one underarm sweat sample per individual was collected. The dog training sessions lasted between one and three weeks. Once trained, the dog had to mark the COVID-19 positive sample randomly placed behind one of three or four olfactory cones (the other cones contained at least one COVID-19 negative sample and between zero and two mocks). During the testing session, a COVID-19 positive sample could be used up to a maximum of three times for one dog. The dog and its handler were both blinded to the COVID-positive sample location. The success rate per dog (i.e., the number of correct indications divided by the number of trials) ranged from 76% to 100%. The lower bound of the 95% confidence interval of the estimated success rate was most of the time higher than the success rate obtained by chance after removing the number of mocks from calculations. These results provide some evidence that detection dogs may be able to discriminate between sweat samples from symptomatic COVID-19 individuals and those from asymptomatic COVID-19 negative individuals. However, due to the limitations of this proof-of-concept study (including using some COVID-19 samples more than once and potential confounding biases), these results must be confirmed in validation studies.

Prevalence, risk factors of infection and molecular characterization of trichomonads in puppies from French breeding kennels.

The trichomonad species Tritrichomonas fetus and Pentatrichomonas hominis were recently identified in the feces of dogs with diarrhea. However the prevalence and pathogenicity of these parasites in the canine population still remained poorly resolved. Therefore the aim of the present study was (1) to determine the prevalence of trichomonads infecting puppies living in French breeding kennels, (2) to confirm the predominance of P. hominis in dogs, (3) to investigate the genetic diversity of P. hominis isolates identified in the French canine population and (4) to evaluate the risk factors for infection by P. hominis and the influence of the parasite on feces consistency. A total of 215 both diarrheic and non-diarrheic puppies from 25 French breeding kennels were included in this epidemiological survey. Fecal samples from each puppy were examined for 6 gastrointestinal pathogens: parvovirus type 2 (CPV2), coronavirus, Toxocara canis, Cystoisospora ohioensis-complex, Cystoisospora canis, and Giardia intestinalis. A part of each collected stool was also tested for the presence of motile trichomonads by microscopy after culturing. The prevalence of trichomonad infection was 15.8% (34/215) among puppies and 20% (5/25) among breeding kennels. DNA from 26 of the 34 positive samples was successfully amplified using a trichomonad-specific primer pair. Analysis of the sequences of PCR products indicated that P. hominis was the only trichomonad infecting the canine population. All the puppies infected with P. hominis belonged to large breed dogs. Moreover, puppies from large breeding kennels, excreting a high level of G. intestinalis and/or excreting a high level of C. canis oocysts showed a higher probability of being positive for P. hominis infection. Univariate analysis also revealed an increased risk for P. hominis infection in puppies with abnormal feces. However, in a multivariate analysis, CPV2 was the only gastrointestinal pathogen associated with abnormal feces. Since enteropathogens were commonly found in dogs infected by P. hominis, the pathogenic potential of this trichomonad species remained uncertain and has to be further evaluated by experimental infection studies.

Fecal calprotectin concentrations in adult dogs with chronic diarrhea.

OBJECTIVE: To evaluate fecal calprotectin concentrations in healthy dogs and dogs with chronic diarrhea, to identify cutoff values for fecal calprotectin concentrations for use in differentiating dogs with chronic diarrhea and a canine chronic enteropathy clinical activity index (CCECAI) < 12 from dogs with chronic diarrhea and a CCECAI ≥ 12, and to evaluate the association between histologic evidence of intestinal mucosal changes and fecal calprotectin concentrations in dogs with chronic diarrhea. SAMPLE: Fecal samples from 96 adult dogs (27 dogs with chronic diarrhea and 69 healthy control dogs). PROCEDURES: Severity of clinical signs was evaluated on the basis of the CCECAI scoring system. Endoscopy was performed in all dogs with chronic diarrhea, and mucosal biopsy specimens were evaluated histologically. Fecal calprotectin concentration was quantified via radioimmunoassay. RESULTS: Fecal calprotectin concentrations were significantly higher in dogs with chronic diarrhea than in healthy control dogs. Fecal calprotectin concentrations were also significantly higher in dogs with a CCECAI ≥ 12, compared with concentrations for dogs with a CCECAI between 4 and 11. Fecal calprotectin concentrations were significantly higher in dogs with chronic diarrhea associated with histologic lesions, compared with concentrations in control dogs, and were significantly correlated with the severity of histologic intestinal lesions. Among dogs with chronic diarrhea, the best cutoff fecal calprotectin concentration for predicting a CCECAI ≥ 12 was 48.9 µg/g (sensitivity, 53.3%; specificity, 91.7%). CONCLUSIONS AND CLINICAL RELEVANCE: Fecal calprotectin may be a useful biomarker in dogs with chronic diarrhea, especially dogs with histologic lesions.

Accuracy of asymmetry indices of ground reaction forces for diagnosis of hind limb lameness in dogs.

OBJECTIVE: To determine the accuracy of asymmetry indices of ground reaction forces (GRF) for diagnosis of hind limb lameness in dogs. ANIMALS: 36 healthy dogs and 13 dogs with naturally acquired cranial cruciate ligament rupture or hip dysplasia. PROCEDURES: Lameness for affected dogs ranged from not detectable to minor and constant. While dogs trotted on an instrumented treadmill, GRF variables were recorded and analyzed with asymmetry indices. Each index was tested for its ability to discriminate between healthy and affected dogs. Combinations of several indices were also assessed. RESULTS: Vertical force variables had better accuracy than craniocaudal force variables. Peak vertical force was the most accurate variable. Partial asymmetry during trotting was detected in healthy dogs. A multivariate approach that used peak vertical force and maximal rising slope yielded the optimum combination to distinguish between healthy and affected dogs. In addition, sensitivity of 92% or specificity of 95% may be achieved with 2 cutoff values while simultaneously maintaining specificity or sensitivity, respectively, at > 85%. CONCLUSIONS AND CLINICAL RELEVANCE: Asymmetry indices of GRFs were accurate for detection of hind limb lameness in dogs. This is particularly relevant for study designs in which only a single gait evaluation is possible.