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Titanium dioxide (TiO2) nanoparticles have a high surface-to-mass ratio and rapidly aggregate in water causing great difficulties for toxicity test exposed to aquatic organisms or other cell lines. This study uses a cell viability kit for routine toxicity test of TiO2 as well as other nanoparticles which accumulate in the aquatic environment. Tetrahymena immediately endocytoses TiO2 nanoparticles and stores them in food vacuoles until the particles undergo exocytosis as larger aggregates. However, during the process of endocytosis and exocytosis, TiO2 particles interfere with cell growth and consequently induce acute toxicity. It exerted high cell growth inhibition at 20 h incubation and induces significant cytotoxic effects. Surprisingly, the effect of TiO2 decreases at 40 h incubation, due to the recovery of cell growth and reduction of the cytotoxicity of the particles.

Background: Diarrhoea is a leading cause of morbidity and mortality in developing countries. This study observed the influences of nutritional status and age on the outcome of severe diarrhoea in adult male patients. Methods and materials: Data were obtained through interview by arranged questionnaire. It is a prospective longitudinal study, where one group of patient was well nourished and other group was malnourished. Results: Significant differences were found in all study factors between malnourished and well nourished diarrhoea patients. Patients with poor nutritional status had low body weight and muscle mass index than well nourished patients. The stool volume was higher in malnourished patients than well nourished patient. In addition mean duration of diarrhoea for malnourished patients was higher than well nourished patients until discharge from hospital. Conclusion: Therefore, the diarrhoea of malnourished and low socioeconomic status of adult patients is more severe, and the incidence of this disease can be reduced by growing awareness as well as improve nutritional and socioeconomic status of those patient groups. Bangladesh Journal of Medical Science Vol. 12 No. 03 July ’13 Page 250-255 DOI: http://dx.doi.org/10.3329/bjms.v12i3.15406

The study has demonstrated that anticancer drug 5-fluorouracil causes acute toxicity and interferes with the growth of green microalgae, Scenedesmus vacuolatus. It accumulates in microalgae biomass with bioaccumulation factor of 1.84 × 10(4) and further integrates into the DNA and RNA of microalgae. In addition, the labelled microalgae genome is transferred into protozoan Tetrahymena pyriformis on feeding and is retained in the food vacuoles of predator organisms. This biotransfer of labelled 5-fluorouracil via genomic material was evaluated using radioactivity in Tetrahymena cell pellets though radioactivity did not detect anticancer drug in the genome of the predator organism.

A high throughput culture methodology of unicellular eukaryote Tetrahymena pyriformis, strain GL were used for the determination of catecholamines toxicity and their metabolism. Catecholamines exhibited acute toxicity to Tetrahymena cells where dopamine and L-DOPA showed higher toxic potential of EC(10) (0.39 and 0.63 mg/L, respectively) and EC(20) (1.1 and 1.0 mg/L, respectively). All the testing catecholamines were highly degradable in the PPY-medium due to the oxidizing environment during incubation. They were also naturally synthesized and released by Tetrahymena cells into the culture medium and increasingly accumulated with time where as noradrenalin demonstrated significant results. Cells were exposed with physiological concentration (0.12 mg/L) and one higher concentration (8.0 mg/L) of catecholamines, resulting noradrenalin depletion and in vivo generation of a metabolite in response to dopamine with higher concentration treatment. This dopamine metabolite was relatively nonpolar compared with the catecholamines and was eluted later from the reverse phase C-18 column.

A 96-well plate culture methodology for the unicellular eukaryote Tetrahymena pyriformis, strain GL was used for the determination of toxicity and metabolism of catecholamines. Catecholamines exhibited moderate acute toxicity to Tetrahymena cells where dopamine and L-DOPA showed higher toxic potential at EC(10) (0.39 ppm and 0.63 ppm, respectively) and EC(20) (1.1 ppm and 1.0 ppm respectively) after 48 h exposure. All tested catecholamines were highly degradable in the PPY-medium due to the oxidizing environment during incubation. Also the catecholamines were naturally synthesized and released by Tetrahymena cells into the culture medium and increasingly accumulated with time where noradrenalin exhibited the highest degree of accumulation. However, the exogenous exposure of catecholamines to the cells caused the depletion of natural noradrenalin synthesis even with the addition of very low physiological concentration (0.12 ppm). Dopamine caused the higher effect on inhibiting noradrenalin synthesis. Treatment with a higher concentration (8.0 ppm) of dopamine in 96-well plates caused strong excitation of the cells and ascertained a new metabolite in vivo while the other representative catecholamines were not responsible for the production of this metabolite. This dopamine metabolite is relatively non-polar as compared to noradrenalin, adrenaline and dopamine and eluting later through the reverse phase C-18 column.