Ultrastructural and histopathological changes in Giardia lamblia-infected hamsters following administration of two natural compounds and/or metronidazol

The use of combined treatment of metronidazole together with arthemisia and rosemary for controlling intestinal Giardia lamblia infection has been studied. Forty laboratory-bred male hamsters were used in the current experimental study. Each hamster was infected, orally, by 10.000 Giardia lamblia cysts. Animals were divided into the following groups: [1] control infected untreated, [2] infected treated with metronidazole, [3] infected treated with arthemisia and rosemary, [4] infected receiving combined treatment of metronidazole plus arthemisia and rosemary. Each treatment was applied three weeks post-infection. Two weeks later stool analysis was performed and the number of cysts/gm stool was counted, followed by scarification of all animals. The effect of the different drug regimens on the vegetative forms [trophozoites] of the parasite was also studied. There was a highly significant cyst reduction in all treated groups compared to control animals. The highest percentage trophozoite reduction [98.7%] was found in group 4 receiving combined treatment of metronidazole plus arthemisia and rosemary, followed by group 2 [94.8%] and group 3 [62.2%]. By histology, healing of mucosal ulcerations, preserved villi and reduced chronic inflammatory infiltrate in the lamina propria were detected with combined therapy. Ultrastructurual examination of the small intestine in animals of control group showed destructed intestinal cell projections by Giardia lamblia cysts with degeneration of the intestinal submucosa. With combined treatment, complete repair of the intestinal cell projections as well as healing of the mucosa and the submucosa were noticed. Meanwhile, partial healing of destructed intestinal cell projections was observed in group 2 receiving metronidazole alone. It was concluded that the best results were obtained following combined treatment of metronidazole together with arthemisia and rosemary. This might be useful in endemic areas where people tend to develop drug resistance to the commonly used anti-Giardia lamblia preparations

A unique mechanism of nuclear division in Giardia lamblia involves components of the ventral disk and the nuclear envelope

The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin directly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge. After the basal bodies become duplicated, a full nuclear division occurs in trophozoites, giving two pairs of parent-daughter nuclei. This full division occurs in a dorsal-ventral direction, with the resulting nuclear pairs located at the sides of the two sets of basal bodies. A new ventral disk is formed from the disk-derived sheets in the cell harboring the four nuclei. Cytokinesis is polymorphic, but at early stages is dorsal-to-dorsal. Encysting trophozoites show the development of Golgi cisternae stacks and dense, specific secretory granules. 3-D reconstructions show that cysts contain a single pair of incompletely strangled nuclei. The dividing Giardia lacks a typical, microtubular spindle either inside or outside the nuclei. The nuclear envelope seems to be the only structure involved in the final division of the parent-daughter nuclei.

Separación de proteínas del disco ventral de Giardia intestinalis / Separation of proteins from the ventral disk of Giardia intestinalis

Mediante separación isoeléctrica y reisoelectroenfoque se obtuvieron las proteínas de citoesqueleto de Giardia intestinalis con características de giardinas y tubulinas, constituyentes principales del disco ventral. El peso molecular fue 30 a 45 kDa así como las de sus variantes determinadas por la diferencia de pH. Además de las mismas se obtuvieron predominantemente polipéptidos de peso molecular de 97 y 115 kDa. Por inmunocitoquímica se demostró que estas proteínas de peso molecular elevado se localizaron sobre la membrana del trofozoíto, y en menor proporción se observaron proteínas con pesos moleculares semejantes a los de giardinas y tubulinas