Electron Microscopy Of Giardia Lamblia In Human Jejunal Biopsies

Abstract

Jamaica PLATES XV-XIXDESCRIPTIONS of the fine structure of Giardia lamblia and its relations to the intestinal mucosa are few. Rossi-Espagnet and Piccardo (1957) examined whole mounts of the parasite with the electron microscope without extending descriptions beyond the light-microscope appearances. Cheissen (1 964) reported on the ultrastructure of Lamblia duodenalis in rabbits. Takano and Yardley (1965) described Giardia larnblia from human intestinal biopsies and more recently Morecki and Parker (1967) described the ultrastructure of the human Giardia, presenting a case in which the parasite had apparently penetrated the mucosal cells. In both these papers fixation was in osmium tetroxide. Friend (1966) reported in detail the ultrastructure of Giardia rnuris, for which he used a glutaraldehyde-acrolein fixative with osmium tetroxide post-fixation.In this paper, we present descriptions of the electron-microscopic appearances of Giardia lamblia, found in jejunal biopsies from three patients and fixed in glutaraldehyde. METHODSPeroral jejunal biopsy was performed with a Watson intestinal biopsy capsule. The biopsy was divided into two parts for light and electron microscopy. The first part was fixed in 4 per cent. formaldehyde and after examination under a dissecting microscope it was embedded in paraffin; sections were stained with haematoxylin and eosin. The other part of the biopsy was fixed for electron microscopy by immediate immersion in 2.5 per cent. glutaraldehyde in 0 . 1~ phosphate buffer (pH 7.4) at 4°C; 1-mm pieces were trimmed and fixation was carried out for 2 hr. After overnight washing in buffer, the tissues were post-fixed in 1 per cent. phosphate-buffered osmium tetroxide, dehydrated through graded alcohols, passed through propylene oxide, embedded in Maraglas and polymerised at 60°C for 18 hr. 1-pm sections were stained with toluidine blue and examined by light microscopy. Thin sections were cut on an LKB Ultrotome with glass knives and stained with uranyl acetate followed by lead citrate, or lead citrate alone (Reynolds, 1963). Electron microscopy was carried out with a Philips 100 C at 60 kV.

Protein trafficking in Giardia lamblia

“…Until just recently, the features of the Giardia ER were unknown. Some authors even suggested the absence of this organelle in Giardia (Brooks et al ., 1970). Some light in this regard came out with the cloning, characterization, and immunolocalization of ER‐resident chaperones: the immunoglobulin heavy chain‐binding protein (BiP) (Craig, 1993; Craig et al ., 1993) and protein disulphide isomerases (PDIs, Nigam et al ., 1994).…”

Malabsorption in Giardiasis

“…It probably depends on the intensity and 'the duration of the infection, as well as on the nutri-:tional and immune state of the host. Often, no ;pathologic changes were identified by either light or gelectron microscopy (19,25,26,28,38,(42)(43)(44). If some lmeasure of damage was discernible, the histologic changes ranged from thickening or blunting of villi (17,18,27,45 -49), to a nearly flat or a flat mucosa (13,17,25,28,38,50).…”

“…Such was probably demonstrated in experimental giardiasis where, in the presence of normal histology, the active transport of glucose and glycine into enterocytes was defective (69). Similarly, a decrease in the absorption of D-xylose in the presence of normal histology (44) suggests the presence of functionally immature enterocytes.…”

Ultrastructural cytochemical identification of peroxisomes as organelles of terminal oxidation in amitochondrial trichomonad flagellates

“…The amitochondrial state has been more commonly reported from flagellates, including the related Intestinal parasites Giardia mur is (Friend, 1967), G^. lamb lia (Brooks et al, 1970), and Lamblia duodenalis (Cheissin, 1964); termite symbionts Trichonympha spp. (Grimstone, 1959), Mixotricha paradoxa (Cleveland and Grimstone, 1964) Joenia annectens and jJ.…”