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KMID : 0381219810130030063
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Journal of RIMSK
1981 Volume.13 No. 3 p.63 ~ p.69
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Study on the Fractions and Amount of Sialoglycoprotein in Gastric Mucosa of the Chronic Peptic Ulcer Patients.
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Abstract
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A clear and accepted role for gastric mucus is that of a lubricant protecting the underlying mucosal cells from mechanical abrasion (Allen, 1980). Another role, suggested by many authors, is that of providing a mixing barries for the containment of HCO3- secretion and restiction of H+ access to the mucosal surface.
Gastric mucus glycoprotein, isolated by equilibrium centrifugation in a CsCI density gradient and studied by ultracentrifugation, had a single component of molecular weight of 2 X 106. Analysis by gel filtration showed four degraded glycoprotein subunits, of about 5 X 105 molecular weight, by pepsin and other proteolytic enzymes. Thermodynamic laws suggest that some starch molecules (though not many) may form covalent bonds with the mucopolysaccharide or mucoprotein chains of the mucous layer of the stomach, producing a gap in this protecting barrier.
The result of this series of reactions will occur only when a sufficient level of starch, a "threshold level", is present in the stomach, such that the stomach is no longer able to repair the injurious effects of the starch -protective barrier reactions. Also, such a threshold level is needed as a thermodynamic driving-force for the aforementioned reaction. Once an initial biochemical break down in the mucous layer occures, the gastric cells would be exposed to HCI by reducing the secretion of HCI, resulting in increased pH, permitting bacterial growth, resulting "intestinalization of the gastric epithelia" and promoting a reaction which produce carcinogenic nitrosamines and/ or nitrosamides, and resulting gastric carcimona formation. Such suggestion can explain the strong positive association of low socio-economic status and orientals with gastric cancer mortality, because of their high intake of starch.
Kabakino et al. reported increased percentage alpha-1 and alpha-2 fractions of the glycoprotein
by the electrophoretic study on the extracted gastric tissue (possibly seromucoid) in comparision with normal control gastric mucosal cells.
And the authors reported that significant increase in amounts of protein-bound carbohydrate and decrease in amounts of seromucoid in the supernatants of gastric mucosal cell homogenates of the gastric ulcer patients in comparision of that of duodenal ulcer patients. Decrease in amounts of seromucoid was most prominent in the incisural area of the stomach, where is well-konown site of predominancy of gastric ulcer.
In order to confirm the previous reports of the authors and compared with report of Kabakino
et al., the authors made electrophoretic study with the same samples of the previous study. The following were ensued;
1. Alpha-1 and-2 fraction percentage were significantly increased in the non-ulcerated region of the ulcer patients.
2. No significant changes could be obtained in the percentage of the each glycoprotein fractions in the ulcerated region and cancer tissue.
3. Percentage of alpha-1 and-2 glycoprotein fractions were significantly increased in the nonecancerous region of the cancer patients.
4. Percentage of alpha-1 and-2 glycoprotein fractions were increased in the pathologic gastric tissue, but it was reversed (decreased) in the incisural mucosal cells.
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KEYWORD
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