An ultrastructural study of osmiophilia in the human rectum

Synopsis Rectal biopsies from subjects with a normal rectum and from patients with various forms of inflammatory bowel disease were studied by the prolonged osmication technique. No consistent ultrastructural differences were observed between these groups, but there were striking differences between individual epithelial cells in the same biopsy and between the epithelium and the cells of the lamina propria. The Golgi apparatus was demonstrated occasionally in the epithelium, often in endothelium. Endoplasmic reticulum, perinuclear cisterna and mitochondria were variably outlined. In plasma cells, there were striking differences in osmiophilia.The underlying mechanism of the different staining patterns is not clear. The findings do not appear to help in the differential diagnosis of inflammatory bowel disease nor to shed any new light on their underlying pathogenic mechanisms.     

Mucosubstances in the normal human oesophageal epithelium

Summary Normal human oesophageal epithelium was investigated with the periodic acid — silver methenamine technique and its variations to demonstrate neutral mucosubstances at the ultrastructural level. The results were compared with the acid phosphotungstic acid method. Neutral mucosubstances were shown in the cell coat and membrane coating granules by both techniques. The silver methods also demonstrated glycogen, the Golgi apparatus and dense bodies. The periodic acid — silver methenamine technique outlined positive material in the intercellular space of the prickle cell layer, but the other silver methods did not.     

The ionic components of normal human oesophageal epithelium

Summary The distribution of cations and anions in normal human oesophageal epithelium has been investigated with the pyroantimonate and silverosmium tetroxide techniques. There is a discontinous distribution of both ions in the intercellular space. The ions are associated with various organelles, as has already been described in the literature. Specifically, in the oesophageal epithelium, there are a few deposits of pyroantimonate and occasional silver in the membrane coating granules, but here is no apparent relationship of either ion with the tonofilaments or glycogen particles. The superficial cells are leaky and contain fewer ions than the deeper functional layer cells.     

The ionic components of normal human oesophageal epithelium.

The distribution of cations and anions in normal human oesophageal epithelium has been investigated with the pyroantimonate and silver-osmium tetroxide techniques. There is a discontinuous distribution of both ions in the intercellular space. The ions are associated with various organelles, as has already been described in the literature. Specifically, in the oesophageal epithelium, there are a few deposits of pyroantimonate and occasional silver in the membrane coating granules, but here is no apparent relationship of either ion with the tonofilaments or glycogen particles. The superficial cells are leaky and contain fewer ions than the deeper functional layer cells.     

The electron microscopy of normal human oesophageal epithelium.

Oesophageal biopsies were studied with the electron microscope. Three layers were identified, as in the light microscopy of the oesophageal epithelium: basal, prickle and funtional cell layers. A continuous basement membrane separated the lamina propria from the basal cells. The basal cell membrane carried hemidesmosomes, desmosomes and microvillous processes. Their cytoplasm contained the usual organelles plus free ribosomes and tonofirbrils. Prickle cells contained glycogen rosettes and many tonofilaments, and their cell membrane many microvillous and demosomal processes, in places elaborated into desmosome fields. In both these layers there was a wide intercellular space containing some particulate and membranous debris. The flattened cells of the functional layer had fewer desmosomes and microvilli but abundant glycogen and tonofilaments, and a narrow intercellular space. Membrane coating granules first reaching a maximum in the functional cell layer appeared in the upper prickle cell layer and few persisted into the surface cells. The apical cell membrane of the most superficial cells was thickened and had few small microvillous processes, which were covered with a filamentous "fuzzy" coat. No keratohyaline granules were present. Papillae of lamina propria contained capillaries, some with a fenestrated endothelium.     

Histochemical studies of mucosubstances and lipids in normal human oesophageal epithelium

Synopsis The histochemistry of lipids and mucosubstances in normal human oesophageal epithelium were studies in biopsies obtained from 24 patients undergoing investigations of the upper gastro-intestinal tract. Neutral fat droplets, 1–2 gmm in diameter, were present in all layers, the greatest number being in the functional layer cells. No unsaturated lipids or fatty acids were demonstrable. Much glycogen was present in the cytoplasm of the prickle and functional cell layers as demonstrated by PAS (and diastase digestion) techniques. The intercellular space of the most superfical of the functional cell layer contained neutral and sialic acid-rich acid mucopolysaccharides. These may be important in protecting the epithelium against physical and chemical trauma.     

Concanavalin a receptors in normal and inflamed oesophageal epithelium

Summary We have examined normal and inflamed oesophageal biopsies for the distribution of -d-mannosyl and -d-glucosyl residues using the concanavalin A — horse radish peroxidase — Diamino-benzidine (DAB) technique at the light and electron microscope level. Receptors were found on the epithelial surface and in the neclear membrane and endoplasmic reticulum. A similar distribution was found with the intrusive lymphocytes and polymorphonuclear leucocytes in the inflamed state. Some of the increased intercellular debris from inflamed biopsies contained concanavalin A receptors.     

The light and electron microscopic distribution of acid phosphatase activity in human normal oesophageal epithelium

Acid phosphatase activity in human normal oesophageal epithelium was studied with light and electron microscopic techniques. The maximum activity was found to be in the prickle and lower functional layers. Electron microscopic examination revealed activity to be localized in GERL, lysosomes and membrane coating granules. These last structures probably secreted their content into the intercellular space in the central part of the functional layer. Thick sections (0.5 micron) with tilting showed GERL to consist of anastomosing tubules.     

Ultrastructural demonstration of cell coat on the cell surfaces of normal human oesophageal epithelium

Synopsis The cell coat in human oesophageal biopsies was studied with Alcian Blue, Ruthenium Red, Safranin O, colloidal iron and the ferrocyanide-osmium tetroxide techniques. Alcianophilic material was found on the cell surface of the basal, prickle cell and functional layers, being most abundant on the superficial cells where it appeared as a continuous coat. In the deeper layers, it tended to have a particulate distribution. Some membrane-coating granules were alcianophilic. Ruthenium Red had a particulate distribution over all cell surfaces. Intercellular debris was also stained. Safranin O produced no staining. Colloidal iron stained the cell coat in a particulate manner. The ferrocyanide-osmium technique showed a uniform filamentous cell coat. The oesophageal epithelial cell coats are, in part, acid mucosubstances which, on the surface cells, may have a protective function.     

An ultrastructural study of the human micropolycystic ovary

The basement membrane of follicles in the micropolycystic ovaries of infertile women was thickened compared to that in the ovaries of normal women or those with typical polycystic ovaries.     

Mucosubstances in the normal human oesophageal epithelium. A comparison of periodic acid-silver and phophotungstic acid techniques.

Normal human oesophageal epithelium was investigated with the periodic-acid-silver methenamine technique and its variations to demonstrate neutral mucosubstances at the ultrastruct level. The results were compared with the acid phosphotungstic acid method. Neutral mucosubstances were shown in the cell coat and membrane coating granules by both techniques. The silver methods also demonstrated glycogen, the Golgi apparatus and dense bodies. The periodic acid-silver methenamine technique outlined positive material in the intercellular space of the prickle cell layer, but the other silver methods did not.     

Asymmetric stem-cell divisions define the architecture of human oesophageal epithelium

In spite of its clinical importance, little is known about the stem-cell compartment of the human oesophageal epithelium [1,2]. The epithelial basal layer consists of two distinct zones, one overlying the papillae of the supporting connective tissue (PBL) and the other covering the interpapillary zone (IBL) [3]. In examining the oesophageal basal layer, we found that proliferating cells were rare in the IBL and a high proportion of mitoses were asymmetrical, giving rise to one basal daughter and one suprabasal, differentiating daughter. In the PBL, mitoses were more frequent and predominantly symmetrical. The IBL was characterised by low expression of ?1 integrins and high expression of the beta2 laminin chain. By combining fluorescence-activated cell sorting (FACS) with in vitro clonal analysis, we obtained evidence that the IBL is enriched for stem cells. A normal oesophageal epithelium with asymmetric divisions was reconstituted on denuded oesophageal connective tissue. In contrast, asymmetric divisions were not sustained on skin connective tissue, and the epithelium formed resembled epidermis. We propose that stem cells located in the IBL give rise to differentiating daughters through asymmetric divisions in response to cues from the underlying basement membrane. Until now, stem-cell fate in stratified squamous epithelia was believed to be achieved largely through populational asymmetry [4-6].     

Carbonic anhydrase is present in human oesophageal epithelium and submucosal glands

Summary Carbonic anhydrase (EC 4.2.1.1) activity was investigated in normal human oesophageal mucosa using the Hansson and Ridderstråle catalytic cobalt methods. The enzyme was detected in the cell membranes and nuclei and, to a lesser extent, in the cytoplasm of the epithelial cells of the mucosa giving a chicken wire appearance. Activity decreased towards the lumen. Other stratified squamous epithelia - buccal mucosa, ectocervix and skin - gave a similar pattern. Acinar cells of oesophageal submucosal glands also exhibited activity for the enzyme, but the ducts did not. The formation of reaction product was prevented by acetazolamide and ethoxzolamide and by the omission of bicarbonate from the substrate medium. Carbonic anhydrase in oesophageal squamous epithelium may be involved in the control of intra- and extracellular pH, while that in the glands is more likely to be concerned with bicarbonate secretion.     

The distribution and mobility of surface anionic groups of normal human oesophageal epithelium following interaction with cationized verritin.

Oesophageal epithelial cells from biopsies from normal patients showed the presence of randomly distributed anionic groups, mostly sialic acid on the cell membrane in fixed material shown by cationized ferritin. When biopsies were pulse labelled, patching occurred in all three cell layers. Patching was energy dependent and did not occur at 4 degrees C. Pulse labelled material incubated on an unlabelled medium showed progressive loss of cationized ferritin from the cell membrane. This was mostly into the medium, although some was internalized in membrane profiles. A second pulse of cationized ferritin produced further patching suggesting regeneration of cell membrane. Superficial cells were leaky, but their organelles were not.     

Age-related changes in the ultrastructural organization of the human gingival epithelium

By means of transmissive and scanning electron microscopy 103 gingival bioptates in practically healthy persons at the age of 18-80 years have been studied. At ageing essential changes take place in all structural elements of the epithelium. The basal membrane is intermittent and loose. In cytoplasm of the cells of the basal layer epithelium the amount of microfilaments increases essentially, and as a result it becomes electron opaque. Tonofibrillar fasciculi of the spinous layer cells are fragmented, their contours are indistinct. In cytoplasm of the granular layer cells amount of keratohyalin granules increases, their size becomes large and their typical form is lost. In cytoplasm of the basal, spinous and granular layer cells the amount of organells decreases. Mitochondria acquire the appearance of electron translucent cavities with discomplexic, and sometimes, destroyed cristae. Rather great changes occur in intercellular interrelations. In all the layers some intercellular spaces are widen, in the spaces formed isolated desmosomes and other debries of cellular structures are formed. Sharp changes of microrelief of the granular layer epitheliocytes are observed. The ultrastructural rearrangements of epitheliocytes, revealed in the human gingiva, demonstrate certain disturbances in keratinization processes, in mechanical firmness, as well as in barrier function of the epithelial layer.