Reversibility of Effects of Very Hypotonic Fluids on in Vitro Frog Gastric Mucosa: A Functional and Morphological Study

Functional and morphological properties of the in vitro frog gastric mucosa were studied during and after exposure to very hypotonic (? 25 mOsM) solutions. Within 20 min the acid secretory rate decreased to zero, but it returned to normal levels after isotonic fluids had been restored. The potential difference (PD) dropped within the first minutes after the exposure to hypotonic solutions, and became inverted. Following the return of isotonic conditions the PD increased to levels higher than in the controls. The electrical resistance increased about 10–fold during the hypotonic period, but decreased to near normal values when isotonic conditions were restored. By light and electron microscopy the cells of the hypotonic mucosae appeared greatly swollen, and the alterations were assessed by morphometric methods. The gland lumina were almost obliterated, and the lamina propria was reduced to about 60% of its former volume. After the return to isotonic conditions normal morphology was restored. It is conceivable that the great increase in resistance during the hypotonic period was caused by the occlusion of the gland lumina. Quantitative analyses of the Na, K, and C1 tissue concentrations indicated a large loss of these ions during the hypotonic state. Presumably the epithelial cells in the hypotonic mucosae avoid bursting by rapidly letting large numbers of ions exit, which results in a cellular osmolarity close to that of the bathing fluids.     

Coxsackievirus B3 replication and persistence in intestinal cells from mice infected orally and in the human CaCo-2 cell line

Although the transmission of coxsackievirus B3 occurs mainly via the oral route, little is known about the primary replication and persistence of this agent in the intestine. To address this question, BALB/c mice were inoculated by gavage with coxsackievirus B3, Nancy strain. The mice were killed from 1 hr to 90 days after infection. The viral markers were detected in the small intestine using RT-PCR, cell culture and detection of VP1 protein. Coxsackievirus B3 was detected positive by the three methods from hr 2 to day 45 after infection. By using monoclonal antibodies directed towards VP1, CD40 and CD26, the virus was shown to be present in the lymphocytes of the mucosa as soon as 2 hr after infection; in contrast, no virus was detected in the epithelial cells lining the intestinal lumen. Further experiments were performed to evaluate the capacity of coxsackievirus B3 to establish a persistent infection in two intestinal cell lines. In contrast to HT29 cells, the CaCo-2 cells were shown to develop a persistent infection for up to 20 passages, as demonstrated by the detection of viral RNA and VP1 protein. This study provides further evidence that, after infection by the oral route, the viral particles are concentrated in the lymphocytes of the mucosal layer. In addition, the results suggest that coxsackievirus B3 is capable of establishing a persistent infection in the small intestine that may act as a reservoir of viral particles for the delayed spread of the virus to other target organs.     

Differential expression of lactoseries carbohydrate epitopes HNK-1, CD15, and NALA by olfactory receptor neurons in the developing chick

 The formation of the nasal lining with its sensory and its nonsensitive respiratory epithelium requires a spatially ordered pattern of cellular differentiation. Aiming at identifying cell recognition molecules that may be involved in cellular differentiation steps, we applied a panel of antibodies to terminal carbohydrate sequences of the lactoseries on the developing chick olfactory epithelium. This approach is based on the idea that these terminal sugar residues may be involved in certain steps of maturation. Restricted expression of three epitopes NALA, HNK-1, and CD15 was observed in olfactory receptor neurons. The first immature olfactory receptor neurons were observed by day 3 of incubation, expressing the HNK-1 epitope, whereas a total epithelial staining was observed for NALA. By day 9 of incubation high numbers of HNK-1 positive immature olfactory receptor neurons were observed. At the same time mature olfactory receptor neurons showed immunoreactivity for CD15, whereas NALA was still expressed throughout the whole epithelial cell population. However, there was a pronounced staining in the population of mature olfactory receptor neurons. Around hatching only CD15 was detectable in (mature) olfactory receptor neurons, whereas HNK-1 and NALA immunoreactivity have switched to glandular and sustentacular cells respectively. The differentiation-dependent expression patterns of these three cell surface molecules suggest them as suitable markers to explore mechanisms that determine embryonic olfactory receptor neurogenesis. Accepted: 15 October 1997     

Antistressor effect of dalargin in rats with immobilization stress

Laboratory of Experimental Surgery, A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. I. Kuzin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 111, No. 6, pp. 617–619, June, 1991.     

The gastric mucosal barrier: tight junction structure in gastritis and ulcer biopsies

Summary Tight junctions of the human gastric mucosa were examined using quantative freeze-fracture methods. Biopsies examined were from patients with gastric diseases including gastritis, ulcers, and pernicious anemia. No significant differences were seen in strand number or tight junction complex depth among the biopsies analyzed, however, anomalous tight junction structures were observed. Discontinuities in the tight junction complex and hyperplastic tight junctions (extensions of the apical tight junction strands radiating over the lateral plasma membrane) were seen. These alterations were not associated exclusively with either the diagnosis of gastritis or ulcers. However, a higher frequency of tight junction breaks was seen in stomach biopsies diagnosed as gastritis while those diagnosed as ulcers displayed a higher occurrence of hyperplastic tight junctions.     

Profilin-mediated food-induced allergic reactions are associated with oral epithelial remodeling

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Intramucosal Helicobacter pylori in the human and murine stomach: its relationship to the inflammatory reaction in human Helicobacter pylori gastritis

Intramucosal Helicobacter pylori (H. pylori) has been described in biopsy tissues and culture systems. However, the association of intramucosal H. pylori with histopathologic features has not been evaluated. The purpose of this study is to investigate the relationship between intramucosal H. pylori and inflammatory reactions in H. pylori infection. In 113 randomly selected human gastric biopsies and 20 murine stomachs, which were inoculated with SSI every day for a week, immunohistochemical analysis for intramucosal H. pylori was done and correlated with histologic parameters. Electron microscopic examination was done on murine stomachs. H. pylori infection was present in 104 gastric biopsies and 17 murine stomachs. Intraepithelial immunopositivity for H. pylori was detected in 27 of 104 (26%) biopsies and in 11 of 17 (65%) murine stomachs. Lamina proprial immunopositivity for H. pylori was present in 51 of 104 (48%) biopsies. Neutrophil-associated immunopositivity for H. pylori was observed in 22 of 90 (24%) biopsies with H. pylori chronic active gastritis. Lamina proprial and neutrophil-associated immunopositivity for H. pylori correlated significantly with the density of H. pylori and the grade of acute inflammatory reaction in H. pylori gastritis. Intramucosal location of H. pylori itself or its antigen is closely associated with acute inflammatory reactions and may play an important role in establishing a persistent infection in chronic H. pylori gastritis. Furthermore, lamina proprial and/or neutrophil-associated H. pylori appears to be more important than intraepithelial H. pylori in acute inflammatory reactions of H. pylori gastritis.     

人鼻腔嗅粘膜嗅鞘细胞的原代培养和免疫组化观察

目的 建立人鼻腔嗅粘膜嗅鞘细胞（OECS）的体外培养方法。方法 利用鼻窦镜选取上鼻甲嗅区粘膜，原代培养嗅鞘细胞，进行形态学观察。结果 成功培养出人鼻腔嗅粘膜OECs，为扁平的双极、多极形态，对P75、GFAP呈阳性反应，纯度在50％左右。结论 人鼻腔嗅粘膜培养OECs的方法实用可行，但须在取材部位和纯化方面进一步探讨。     

Interepithelial cells of the oral mucosa in mice

Summary Non-epithelial mesenchymal and neuroectodermal cells occur between the keratinocytes in the stratified squamous epithelium of the oral mucosa. These cells cannot be classified adequately by light microscopy. In the present study the oral mucosa of the lip, cheek and tongue of 50 mice were studied by light and electron microscopy. 3,025 mononuclear interepithelial cells were documented and analysed.Monocytogenic macrophages, plasma cells and mast cells were not found interepithelially and cannot be regarded as a regular constituent of the epithelium. Only a few neuroectodermal cells — in mice these are exclusively Merkel cells, with no melanocytes — were localized in the epithelium. The majority of the interepithelial cell population is made up of lymphocytes (22.8%) and Langerhans cells (56.8%). They are an integral constituent of the epithelium. Lymphocytes with rounded and indented nuclei can be identified. The larger and dendritic Langerhans cells are a specific cell of squamous epithelium and also occur in the oral mucosa. Not all cells which feature the cytological characteristics of Langerhans cells contain Langerhans or Birbeck granules. Accordingly these granules cannot be considered an exclusive identification characteristic. Two types of Langerhans cells can be differentiated. 80.9% have the more or less typical appearance known from the epidermis and were termed macrophagocytoid Langerhans cells. The nuclei are irregularly indented and moderately heterochromatic. 19.1% possessed conspicuous large, spherical, euchromatic nuclei and an electron-lucent cytoplasm. These were termed reticuloid Langerhans cells. About 20% of the interepithelial cell population could not be identified, neither as typical lymphocytes nor as Langerhans cells. These were small to medium sized cells with deeply indented cerebriform strongly heterochromatic nuclei. They are similar to the Sézary cells or mycosis fungoides cells of epidermotropic human T-cell lymphomas. The lymphocytic nature of these cells has been confirmed. It seems likely that differentiation of lymphocytes to cerebriform cells occurs within the epithelium. It is further discussed whether cerebriform cells are precursors of Langerhans cells, a conclusion suggested morphologically by transitional forms. This would imply that Langerhans cells originate from lymphocytes, and that the cerebriform cell is an intermediate step of differentiation. The microenvironment of the squamous epithelium may play a role in the process of differentiation, which could explain the epitheliotropy of lymphocytes. The possibility is considered that Langerhans cells and interdigitating reticulum cells of the T-cell area of lymph nodes are identical. The close functional cooperation of Langerhans cells, lymphocytes, and interdigitating reticulum cells in immunological defenses against external antigens is discussed.The authors wish to express their sincere appreciation to Miss P. Starck and Miss I. Brandt for invaluable technical assistance in this project.