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Cyclospora cayetanensis: Portrait of an Intriguing and Enigmatic Protistan Parasite
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Annunziata Giangaspero, Robin B. Gasser
Cyclospora oocysts sporulate using 2.5% potassium dichromate [5] and this occurs in 7–13 days at temperatures between 22°C and 32°C [27]. The two sporocysts are then visible by light microscopy [5,26]. Unsporulated oocysts contain developing sporocysts (which can resemble a raspberry), whereas sporulated oocysts contain two ovoid sporocysts, each containing two sporozoites (Figure 53.1). Storage at either 4°C or 37°C retards sporulation, and it is prevented after 2 days at −20°C or −70°C and 70°C for 15 min [28]. Up to 12% of human- and baboon-associated oocysts previously stored at 4°C per 1–2 months sporulated when stored for 6–7 days at 30°C [26]. It is important to underline that when samples in 2.5% potassium dichromate were submitted to molecular assay for confirmation, this method showed greater sensitivity than microscopy [196]. Excystation can be induced in vitro by exposure to bile salts, sodium taurocholate and mechanical pressure [6].
Prospects of Local Flora of Trans-Himalayan Region of Ladakh for Various Medicinal Uses
Published in Parimelazhagan Thangaraj, Medicinal Plants, 2018
Gyan P. Mishra, Tsering Stobdan, Parimelazhagan Thangaraj, Tania Seth, Bijendra Singh
Sea buckthorn has been studied extensively for its antioxidant properties. The leaf extract of sea buckthorn has been evaluated on chromium-induced oxidative stress. Male albino rats fed with potassium dichromate equivalent to a dose of 30 mg/kg body weight of chromium (VI) for 30 d resulted in a decreased body weight and an increased organ to body weight ratio. The leaf extract of sea buckthorn at a concentration of 100 and 250 mg/kg body weight protected the animals from chromium-induced oxidative injury. Similarly, the cytoprotective and antioxidant properties of the alcoholic leaf extract of sea buckthorn against hypoxia-induced oxidative stress in C-6 glioma cells have been demonstrated. Exposure of cells to hypoxia for 12 h resulted in a significant increase in cytotoxicity and a decrease in mitochondrial transmembrane potential compared to the controls. An appreciable increase in nitric oxide, reactive oxygen species (ROS) production and DNA damage has been observed. The pre-treatment of cells with the alcoholic leaf extract of sea buckthorn (200 μg/mL) significantly inhibited cytotoxicity and ROS production, and maintained antioxidant levels similar to that of control cells. Sea buckthorn extraction procedures also had significant effects on antioxidant activities. Microwave-assisted extracts had significantly higher antioxidant capacity than those obtained by ultrasound-assisted extraction and maceration (Sharma et al. 2007).
Adrenal Tumors
Published in Dongyou Liu, Tumors and Cancers, 2017
Pheochromocytoma varies from a small, circumscribed to a large, hemorrhagic, and necrotic lesion (mean 7 cm/200 g). A fresh tumor turns dark brown in the presence of potassium dichromate at pH 5–6 (chromaffin reaction). Microscopically, the tumor shows zellballen (small nests or alveolar pattern), trabecular, or solid patterns of polygonal/spindle-shaped cells in a rich vascular network, with finely granular basophilic or amphophilic cytoplasm, oval nuclei, prominent nucleolus, variable inclusion-like structures, and rare mitotic figures.
Jean-Martin Charcot´s medical instruments: Electrotherapeutic devices in La Leçon Clinique à la Salpêtrière
Published in Journal of the History of the Neurosciences, 2021
Francesco Brigo, Albert Balasse, Raffaele Nardone, Olivier Walusinski
In 1850, Eugène Grenet (?–1909) proposed his battery (Grenet battery, pile de Grenet; Balasse 2016) as an evolution of that invented by Johan Christian Poggendorff (1796–1877) in 1842. Poggendorff, a famous physicist at the University of Berlin, replaced the nitric acid in Robert Wilhelm Bunsen’s (1811–1899) battery with potassium bichromate dissolved in sulfuric acid. This innovation had the advantage of not spreading corrosive acid fumes. Instead, this safer practice facilitated its more frequent use, although potassium bichromate is also a toxic product. Grenet improved the battery by replacing the initial porous vase with a spherical glass bottle, closed with a hard rubber lid. This single-liquid battery has amalgamated graphite-zinc electrodes (Cadiat and Dubost 1885). These electrodes, previously soaked in mercury, plunge into a bichromate solution with an amber color, which was accurately depicted by André Brouillet within the glass bottle. Grenet batteries vary in size from 13 to 25 cm high (Grenet 1859).
Toxicity of mixtures of zinc oxide and graphene oxide nanoparticles to aquatic organisms of different trophic level: particles outperform dissolved ions
Published in Nanotoxicology, 2018
Nan Ye, Zhuang Wang, Se Wang, Willie J. G. M. Peijnenburg
Daphnia magna, originally obtained from Jiangmen Hongguang Hi-Tech Biological Co., Ltd (Jiangmen, China), was selected as the test species. The OECD Guideline 202 with slight modifications was used to test the acute toxicity of the studied toxicants to D. magna (OECD, 2004). The toxicity tests were performed using newborn neonates (<24 h old). Five individuals were transferred into a test vial, containing 50 mL of the test toxicants or control. Daphnids were exposed to increasing initial concentrations of the ZnO NPs (from 0.01 to 0.4 mg/L), ZnCl2 (from 0.125 to 8 mg/L), and the GO NPs (from 1 to 80 mg/L). Each exposure concentration was tested with three parallels. Each assay was repeated with different batches of daphnids at three different times and the data presented are the mean of the runs (n = 3). Daphnids were incubated under a 10:14 h light/dark photoperiod (20 ± 1 °C) without feeding during the 48 h exposure period. After 48 h, the immobility was examined by activation of the animals by slightly shaking the test vial and monitoring them for 30 s upon agitation of the suspension. Toxicity of potassium dichromate was assessed as a positive control to strengthen the quality control of the D. magna acute toxicity tests.
Terminalia ferdinandiana Exell. Fruit and Leaf Extracts Inhibit Proliferation and Induce Apoptosis in Selected Human Cancer Cell Lines
Published in Nutrition and Cancer, 2018
Potassium dichromate (K2Cr2O7) (AR grade, Chem-Supply, Australia) was prepared as a 1.6 mg/ml solution in distilled water and was serially diluted in artificial seawater for use in the Artemia franciscana nauplii bioassay. Toxicity was tested using a modified A. franciscana nauplii lethality assay (19,20). Briefly, 400 µl of seawater containing approximately 38 (mean 38.1, n = 125, SD 12.6) A. franciscana nauplii were added to wells of a 48 well plate and immediately used for bioassay. A volume of 400 µl of diluted plant extracts or the reference toxin were transferred to the wells and incubated at 25 ± 1°C under artificial light (1000 Lux). A negative control (400 µl seawater) was included on each plate. All treatments and controls were performed three times in triplicate. The wells were checked at regular intervals and the number of dead were counted. The nauplii were considered dead if no movement of the appendages was observed within 10 s. After 24 h, all nauplii were sacrificed and counted to determine the total % mortality per well. The LC50 with 95% confidence limits for each treatment was calculated using probit analysis.