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Some other groups and circumstances
Published in Geoffrey P. Webb, Nutrition, 2019
Even though overt vitamin B12 deficiency is rare even in vegans, their serum concentrations are generally lower than those of omnivores and other less strict vegetarians have intermediate values. Vegans who do not take effective supplements may well have suboptimal status for the vitamin even though they may not show the usual overt symptoms. The low incidence of B12 deficiency in some developing countries where a largely vegan diet is the norm may be because of higher levels of contamination of food and water with bacteria. It is now clear that in some products marketed and used as B12 supplements by vegans, the vitamin is present in an inactive form. The blue-green algae Spirulina e.g. contains an analogue of vitamin B12 which is detected by the microbiological assays used to measure vitamin B12 but it is not biologically active. Some of these analogues may actually worsen the effects of B12 deficiency by interfering with metabolism or absorption of the active form.
Cyclospora cayetanensis: Portrait of an Intriguing and Enigmatic Protistan Parasite
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Annunziata Giangaspero, Robin B. Gasser
Humans infections documented in two children and a woman in Papua New Guinea, which were attributed to Isospora [10], in travelers returning from Mexico and Haiti, and in other cases later attributed to a “coccidian body” [11], may have been caused by Cyclospora. It cannot be excluded that a “large Cryptosporidium” [12] or a Cyanobacterium-like organism/coccidian-like body’/“blue-green algae” detected in a patient with diarrhea [13,14], or with AIDS [15], or in travelers [16,17] may have been due to Cyclospora. This mystery was resolved with the description of the controversial pathogen in some fecal samples from humans from Peru as a new coccidian species named Cyclospora cayetanensis [5,6], phylogenetically closely associated to the Eimeria genus [18], and nowadays molecularly related to avian Eimeria species [9].
Gastrointestinal Function and Toxicology in Canines
Published in Shayne C. Gad, Toxicology of the Gastrointestinal Tract, 2018
The variations of the timing and duration of biological activity in living organisms occur for many essential biological processes. These occur (1) in animals (eating, sleeping, mating, hibernating, migration, cellular regeneration, etc.), (2) in plants (leaf movements, photosynthetic reactions, etc.), and (3) in microbial organisms such as fungi and protozoa (biochemical and metabolic processes). They have even been found in bacteria, especially among the cyanobacteria (e.g., blue-green algae). The most important rhythm in chronobiology is the circadian rhythm, a roughly 24-hours cycle demonstrated in the physiological processes in all these organisms. The term “circadian” comes from the Latin circa, meaning “around” and dies, “day,” meaning “approximately a day.” It is regulated by circadian clocks.
Cyanotoxin genotoxicity: a review
Published in Toxin Reviews, 2022
Serkan Yilmaz, Taha Gökmen Ülger, Bayram Göktaş, Şahlan Öztürk, Duygu Öztaş Karataş, Ebru Beyzi
Cyanobacteria, which can also be named under different names, such as cyanoprocaryotes, cyanophytes and blue-green algae, are prokaryotic organisms without real nuclei and plastids, they differ from other algae groups due to their prokaryotic structure, and they have common features with other algae due to their photosynthesis (Palinska and Surosz 2014). Approximately 2000 strains of cyanobacteria belonging to approximately 150 specıes have been identified on earth, and these strains can be found colonially in all kinds of habitats from seas, soil, hot waters to cold surfaces (Pulz and Gross 2004). Cyanobacteria, which have important ecological roles in the carbon and nitrogen cycles, especially Spirulina, Anabaena, Nostoc and Oscillatoria genus, produce many secondary compounds with peptide, alkaloid and polysaccharide structure (Singh 2016). Though some of the secondary metabolites can be used as therapeutic raw materials because of their antitumor, antifungal and anti-inflammatory effects and siderophores, phytohormones, photoprotective compounds and protease inhibitors (Sinha and Häder 2008), some toxins show negative effects on health due to their hepatotoxic, dermatoxic, neurotoxic, cytotoxic and genotoxic effects (De La Cruz et al. 2020). To date, up to 40 cyanobacterial strains have been identified as generating potential cyanotoxin production in surface water and the main strains in this group are Anabaena, Aphanizomenon, Microcystis, Nodularia and Cylindrospermopsis (Cirés et al. 2017).
Mycotoxicosis – diagnosis, prevention and control: past practices and future perspectives
Published in Toxin Reviews, 2020
These methods, however, have many drawbacks regarding diagnosis of mycotoxicosis. These lesions may be so nonspecific that they do not give a clue to a specific cause. Hepatic necrosis, for example, is a typical lesion which may be caused by any type of toxicity (blue-green algae). The toxic effects of mycotoxins may be masked by secondary effects which appear as primary effects (bacterial, viral, or fungal infection in case of immunosuppression). Mycotoxicosis often aggravates in the presence of more than one mycotoxin and the interaction of mycotoxins produces even more adverse effects than that of individual mycotoxin, and in such cases, diagnosis of a single mycotoxin on the basis of biological methods becomes more confusing (Schiefer 1986). Due to less sensitivity and specificity, these methods are only used for the screening of generalized toxicity (Eppley 1975).
Evolving therapeutic strategies for advanced hepatocellular carcinoma
Published in Expert Opinion on Pharmacotherapy, 2021
Ammar Qureshi, Miguel Michel, Jaren Lerner, Constantin A. Dasanu
The majority of patients who develop HCC have underlying liver disease which can be a result of chronic alcohol intake or chronic infection with hepatitis B or C (HBV or HCV). In the last decades, there has also been a substantial increase in the diagnosis of nonalcoholic fatty liver disease (NAFLD). NAFLD, often a companion of metabolic syndrome and obesity, is gaining headway to become the new leading cause of liver cancer in Western countries [7]. In the United States, the incidence of NAFLD is projected to increase by 122% between 2016 and 2030 [8]. The risk of developing HCC is increased in subjects with underlying liver cirrhosis, with an annual incidence ranging between 2% and 4%. This risk is lower in patients without underlying liver disease. The overall risk of liver cancer varies depending on the etiology, geographic area, gender (being twice as common in men than in women), age, and the degree of liver disease [9]. Despite the decreased incidence of HCC due to HBV vaccination in many countries, HBs antigen carriers remain at elevated risk for developing HCC, with a majority being in Asia and Sub-Saharan Africa [10]. With respect to HCV infected patients, there is a reported reduction in the risk of developing HCC in patients treated with DAAs (Direct-acting antivirals) [11]. Important, yet less prevalent, risk factors for HCC are hereditary hemochromatosis, primary biliary cirrhosis, Wilson’s disease, porphyria cutanea tarda, and alpha-1 antitrypsin deficiency. Several environmental exposures are known to increase the risk of developing HCC, such as aflatoxin, betel nut chewing, tobacco, and drinking water contaminated with microcystin toxin from blue-green algae.