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Balantidium coli
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Alynne da Silva Barbosa, Laís Verdan Dib, Claudia M. Antunes Uchôa
Balantidium coli has two stages in its life cycle: trophozoites and cysts (Figure 50.1). Trophozoites are an active form of the protozoan.13 Being pleomorphic, they vary greatly in size and shape depending on the amount of food ingested, and may appear rounded and large or elongated and thin or small.4,14 Overall, trophozoites can range from 30 to 300 μm in length and from 30 to 100 μm in width.4 Trophozoites have an anterior region that is more tapered and a posterior region that is more rounded. At the anterior end the parasite has a funnel-shaped depression known as the peristome, which leads to the cytostome (also called the mouth) and the cytopharynx, that is, the interior oral cavity (Figure 50.2).13,15
The Protozoa
Published in Donald L. Price, Procedure Manual for the Diagnosis of Intestinal Parasites, 2017
The fixed trophozoite is usually from 10 to 15 μm in length, depending on how much it is rounded (see Plates 38 and 52). It has a round nucleus usually with a karyosome and some peripheral chromatin. The typical appearance of the trophozoites fixed in MIF or PIF is depicted in Plate 52:1–3. Generally, the trophozoite is asymmetrically pear-shaped, rounded at the anterior end, and pointed at the posterior end (see Plates 38 and 52). A spiral torsion of the body is located near the center of the trophozoite but is not always visible. It has a rounded nucleus lying close to the anterior end, often seen with a small karyosome and irregular peripheral chromatin. The trophozoites have three external flagella, one longer than the others, each originating from a blepharo-plast just anterior to the nucleus. A cleft-shaped cytostome with its central cytostomal flagellum lies just below the nucleus (see Plate 38). Food particles ingested through the cytostome, are collected in vacuoles formed at its posterior end, and circulate through the cytoplasm.
Is the hepatocyte ultrastructural zonal heterogeneity changed by overnight (16 h) fasting? Morphometric study
Published in Ultrastructural Pathology, 2019
Hassan Reda Hassan Elsayed, Eman Mohammad El Nashar, Mostafa Mohammed Abd-Elmonem
In the periportal hepatocytes from the fed group, SER was fewer but more tubular within the small restrict regions of cytosome and was displaced to the periphery of the glycogen masses in contrast to the fed centrilobular hepatocytes showing abundant and interspersed SER between individual glycogen particles. After fasting, SER becomes more numerous in both zones, predominantly of vesicular form appeared in many regions of the cytosome of periportal hepatocytes.