Polystyrene microparticles can affect the health status of freshwater fish - Threat of oral microplastics intake.

Plastic waste pollution is considered one of the biggest problems facing our planet. The production and use of these materials has led to huge amounts of plastic waste entering the aquatic environment and affecting aquatic life. In our experiment, the effect of polystyrene microparticles (PS-MPs; 52.5 ± 11.5 µm) on individual juvenile rainbow trout (Oncorhynchus mykiss) was tested at three different dietary concentrations of 0.5, 2 and 5 % for six weeks. At the end of the experiment, various health parameters of exposed organisms were compared with the control group. The haematological profile revealed an immune response by a decrease in lymphocyte count with a concurrent increase in the number of neutrophil segments at the highest concentration of PS-MPs (5 %). Biochemical analysis showed significant reductions in plasma ammonia in all tested groups, which may be related to liver and gill damage, as determined by histopathological examination and analysis of inflammatory cytokines expression. In addition, liver damage can also cause a significant decrease in the plasma protein ceruloplasmin, which is synthesized in the liver. PS-MPs disrupted the antioxidant balance in the caudal kidney, gill and liver, with significant changes observed only at the highest concentration. In summary, PS-MPs negatively affect the health status of freshwater fish and represent a huge burden on aquatic ecosystems.

Non-steroidal anti-inflammatory drugs caused an outbreak of inflammation and oxidative stress with changes in the gut microbiota in rainbow trout (Oncorhynchus mykiss).

One of the main contributors to pharmaceutical pollution of surface waters are non-steroidal anti-inflammatory drugs (NSAIDs) that contaminate the food chain and affect non-target water species. As there are not many studies focusing on toxic effects of NSAIDs on freshwater fish species and specially effects after dietary exposure, we selected rainbow trout (Oncorhynchus mykiss) as the ideal model to examine the impact of two NSAIDs - diclofenac (DCF) and ibuprofen (IBP). The aim of our study was to test toxicity of environmentally relevant concentrations of these drugs together with exposure doses of 100× higher, including their mixture; and to deepen knowledge about the mechanism of toxicity of these drugs. This study revealed kidneys as the most affected organ with hyalinosis, an increase in oxidative stress markers, and changes in gene expression of heat shock protein 70 to be signs of renal toxicity. Furthermore, hepatotoxicity was confirmed by histopathological analysis (i.e. dystrophy, congestion, and inflammatory cell increase), change in biochemical markers, increase in heat shock protein 70 mRNA, and by oxidative stress analysis. The gills were locally deformed and showed signs of inflammatory processes and necrotic areas. Given the increase in oxidative stress markers and heat shock protein 70 mRNA, severe impairment of oxygen transport may be one of the toxic pathways of NSAIDs. Regarding the microbiota, an overgrowth of Gram-positive species was detected; in particular, significant dysbiosis in the Fusobacteria/Firmicutes ratio was observed. In conclusion, the changes observed after dietary exposure to NSAIDs can influence the organism homeostasis, induce ROS production, potentiate inflammations, and cause gut dysbiosis. Even the environmentally relevant concentration of NSAIDs pose a risk to the aquatic ecosystem as it changed O. mykiss health parameters and we assume that the toxicity of NSAIDs manifests itself at the level of mitochondria and proteins.

Do foodborne polyethylene microparticles affect the health of rainbow trout (Oncorhynchus mykiss)?

Due to the fact that plastic pollution is a global environmental problem of modern age, studies on the impact of these synthetic materials on aquatic, and especially fish organisms, are an important part of the ecosystem and human nutrition. In our study, the toxicity of pristine polyethylene (PE) microparticles (approx. 50 µm) on rainbow trout (Oncorhynchus mykiss) was tested in three different dietary concentrations - 0.5%, 2% and 5%. After six weeks of exposure, various health indices were evaluated. Electron microscopy of the intestine revealed the disintegration of PE particles to <5 µm in size, and thus we concluded that microplastics are able to reach tissues. The haematological profile revealed changes in total red blood cells count and haematocrit (5% PE) which could be associated with spleen congestion observed histologically. The marker of lipid peroxidation was increased in gills suggesting the disruption of balance in antioxidant enzymes capacity and histopathological imaging revealed inflammation in higher PE concentrations. In addition, ammonia was decreased and calcium elevated in biochemical profile, confirming the gill damage. Electron microscopy of the gills showed lesions of lamellae and visible rings around the mucinous cell opening indicating their higher activity. Another injured was the liver tissue, as confirmed by hepatodystrophies and increased expression of pro-inflammatory genes in 2% PE. Impaired innate immunity was confirmed by an increased presence of mucinous cells and a decrease in leukocytes. Kidney damage manifested itself by higher expression of pro-inflammatory cytokines and histopathology. The damage in gills, liver and kidney together correlated with the increased antioxidant capacity of plasma. In conclusion, PE microparticles are able to affect health indices of O. mykiss. The potential problem for aquatic ecosystems and even human consumption should be considered.

Could the musk compound tonalide affect physiological functions and act as an endocrine disruptor in rainbow trout?

In the present study, the effect of polycyclic musk compound tonalide (AHTN) in two concentrations was studied in male rainbow trout (Oncorhynchus mykiss, Walbaum 1792). A feeding trial was conducted with AHTN incorporated into feed granules. One concentration was environmentally relevant (854 µg/kg); the second one was 10× higher (8699 µg/kg). The fish were fed twice a day with the amount of feed at 1 % of their body weight. After an acclimatization period, the experimental phase in duration of six weeks followed. At the end of the experiment, fish were sampled and the biometrical data were recorded. Subsequently, hematological and biochemical tests, histopathological examination, analysis of oxidative stress markers and evaluation of endocrine disruption using plasma vitellogenin were performed. In conclusion, an increase of hematocrit for both AHTN concentrations was found, but no significant changes were observed in biochemical profile. Moreover, AHTN caused lipid peroxidation in caudal kidney tissue, which was confirmed by histopathological images. The long-lasting AHTN exposure could thus be harmful for maintaining homeostasis in the rainbow trout organism. However, the vitellogenin concentration seemed not to be affected by AHTN.

Distribution of mast cells in the feline ovary in various phases of the oestrous cycle.

This study is the first description of the distribution of mast cells in various phases of the oestrous cycle in the ovary of cat. Furthermore, this is the first description in species with an induced ovulation. The aim was to describe the distribution of mast cells and variability of their numbers in the feline ovaries in different phases of the oestrous cycle. The number of mast cells in medulla ovarii was affected by the estradiol and progesterone level in the blood serum because the lowest number was detected in anoestrus when the levels of hormones were basal. Nevertheless, both high and low numbers of mast cells were found in oestrus and dioestrus. To conclude, mast cells seem to be essential for the induction of spontaneous ovulation, but they do not play the same role for ovulation itself in cats with induced ovulation.

A new type of plasma knife and its effect on biological issues--a pilot study.

BACKGROUND: Currently, several types of plasma discharge devices have become established for performing surgical procedures or superficial sterilization. Our goal is to introduce a brand new type of plasma discharge device with different characteristics, which we have used for two experiments involving thermal damage to biological tissues. MATERIAL AND METHODS: A plasma discharge device with the following characteristics was used for all incisions in plasma group: radio frequency barrier discharger at atmospheric pressure with a working frequency of 13.56 MHz. The working gas was Argon. We used a Cesar 136 generator with typical power 100-150W and with a working gas flow rate between 0.5 and 3 litres per minute. The inner diameter of the end of the nozzle was 0.4mm. A standard Martin electrotome was used for all comparative incisions in the electrotome group. We used two experimental fresh rat cadavers, employing their skin, tails, lungs, livers, kidneys and spleens to make a comparative study between incisions made with a plasma discharge knife and those made with a standard electrotome device. All samples underwent histological verification. DISCUSSION: Our experiment showed slight differences in the impact on incision edges made by the plasma knife and the electrotome. The most interesting effect is on the skin: the plasma knife does not damage hair bulbs, and it results in less thermal damage. The plasma discharge knife is a promising device for cutting various biological tissues. Its effect can be compared with a standard electrotome, while in some tissues it causes less harm then an electrotome. Moreover, we can adjust its therapeutic effect. However, we do not consider the plasma knife a better choice at present, because maneuvering it is unwieldy.

Woven vascular microsurgical prostheses in our experimental practice.

The authors have been concerned for six years with the development of woven microsurgical prostheses in experiments on laboratory rats, beagle dogs and domestic white pigs. In rats, in 224 experiments employing 38 types of prostheses with an inner diameter of 2 mm, a reliable prosthesis was selected, described as No. 36, with a 100% patency after insertion of a 1 cm long portion into a defect in the abdominal aorta in 40 experiments. The follow-up of this type of prosthesis lasted 12 months. In large animals this type of prosthesis was implanted into a defect of the radial artery and cephalic vein in dogs and into the femoral artery and the artery of a vascular pedicle of groin and lateral thigh flap. These experiments on large animals are not yet complete and will be the subject of a separate paper.

Semi-automated high-performance liquid chromatographic determination of cyclosporine A in whole blood using one-step sample purification and column-switching.

A highly sensitive and semi-automated high-performance liquid chromatographic method, utilizing acetonitrile protein precipitation and column-switching, is described for the determination of cyclosporine A in whole blood. Following a rapid manual acetonitrile treatment of the blood samples, the supernatant is loaded automatically onto a 5-micron high-speed protein separation column without any further clean-up operations. The fraction containing cyclosporine A is switched to a 3-micron C18 reversed-phase high-speed column by a microprocessor-controlled column-switching unit for final separation and detection by absorption at 214 nm. Minimal sample handling and efficient separation resulted in a high recovery (75 +/- 3%) of cyclosporine A from blood and a detection limit as low as 2 micrograms/l with a highly reproducible and linear response up to 2500 micrograms/1 using 0.5 ml of sample. A separation cycle including regeneration of the first column is finished in 15 min, and this system was used continuously for ca. 1000 blood samples from heart, liver, kidney, pancreas and bone marrow recipients without change in separation parameters or material replacement. The method described allows accurate and very fast daily routine monitoring of cyclosporine A in large numbers of blood samples from transplant recipients.