R T Spychal

St. George's School, Middletown, Rhode Island, United States

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Publications (5)51.28 Total impact

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    ABSTRACT: Surface hydrophobicity of the gastric mucosa is reduced in peptic ulcer disease and Helicobacter pylori infection. This abnormality may be caused by H. pylori or may be an inherent defect. The aim of the present study was to clarify the relationship between H. pylori infection and mucosal hydrophobicity by examining the effect of eradication of the organism. H. pylori-positive patients with (n = 42) or without (n = 42) duodenal ulcer were randomized to receive ranitidine, bismuth, or bismuth plus antibiotics. Surface hydrophobicity of gastric mucosa was assessed by measurement of plateau-advancing contact angle. Measurements were performed at presentation, end of treatment, and 1 month later. Contact angle was unchanged after ranitidine (55 degrees vs. 56 degrees) but increased with bismuth (57 degrees-62 degrees; P < 0.05) and bismuth plus antibiotics (56 degrees-67 degrees; P < 0.0001). One month after treatment ended, contact angles in patients in whom H. pylori was not eradicated were not different from those before treatment (56 degrees vs. 56 degrees) but increased to a value similar to H. pylori-negative controls in patients in whom H. pylori was eradicated (56 degrees-69 degrees; P < 0.0001). It is concluded that reduced mucosal hydrophobicity in peptic ulcer disease is secondary to H. pylori infection and that this impaired mucosal defense provides a possible mechanism whereby H. pylori infection predisposes to acid/peptic digestion.
    Gastroenterology 11/1992; 103(5):1486-90. · 12.82 Impact Factor
  • P M Goggin, T C Northfield, R T Spychal
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    ABSTRACT: Contact angle measurements in animal studies have demonstrated that gastric mucosa has a relatively hydrophobic surface. We have developed and validated a technique for the measurement of this property on human endoscopic biopsy specimens. Mean contact angle of the gastric body (70 degrees) and antrum (70 degrees) was higher than the duodenal bulb (62 degrees; p less than 0.01) and distal duodenum (50 degrees; p less than 0.001). Subjects with duodenal ulcer and gastric ulcer had a lower contact angle than controls without ulcer (57 degrees, n = 49, and 59 degrees, n = 17 versus 66 degrees, n = 124, respectively). Helicobacter pylori infection was associated with reduced contact angle in subjects with gastritis (59 degrees versus 68 degrees). The contact angle was unchanged after treatment with ranitidine but increased to control values after clearance and eradication of H. pylori with bismuth and antibiotics. In postgastrectomy patients, the contact angle was reduced and correlated negatively with the bile acid content of gastric juice (r = 0.51, p less than 0.0001). We conclude that in man gastric mucosal hydrophobicity can be validly measured on endoscopic biopsy specimens and that it is high in health and reduced in bile reflux and in peptic ulcer disease, largely as a result of H. pylori infection.
    Scandinavian journal of gastroenterology. Supplement 02/1991; 181:65-73.
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    ABSTRACT: The surface thermodynamic effects of bile acids in the stomach were assessed in 48 subjects who had undergone gastric surgery for peptic ulcer disease and in 52 controls with medically healed ulcers. We derived values for surface tension of gastric mucosa from contact angle using a goniometer and measured the surface tension of gastric juice by the drop-weight method. Subjects with gastric surgery had higher median fasting bile acid concentrations than controls (1.2 vs. 0.1 mmol/L; P less than 0.0001), higher mean mucosal surface tension (51.9 vs. 47.9 mN/m; P less than 0.0001), and lower mean surface tension of gastric juice (43.2 vs. 51.7 mN/m; P less than 0.0001). Subjects who had had a Billroth II gastrectomy (n = 19) had higher bile acid concentrations (5.8 vs. 0.6 mmol/L; P less than 0.01), higher mucosal surface tension (53.7 vs. 50.3 mN/m; P less than 0.05), and lower gastric juice surface tension (41.3 vs. 47.1 mN/m; P less than 0.05) than those who had a vagotomy and drainage procedure (n = 17). Overall, intragastric bile acid concentration correlated directly with surface tension of gastric mucosa (r = 0.51, P less than 0.0001) and inversely with that of gastric juice (r = -0.60, P less than 0.0001). In conclusion, the interfacial energy barrier at the surface of the gastric mucosa is overcome in the presence of intragastric bile acids.
    Gastroenterology 09/1990; 99(2):305-10. · 12.82 Impact Factor
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    ABSTRACT: The hydrophobicity of biopsy specimens of gastric mucosa in 228 dyspeptic subjects undergoing diagnostic endoscopy was assessed by measuring the plateau-advancing contact angle of saline drops using a goniometer. Subjects with duodenal ulcers (n = 49) and gastric ulcers (n = 17) had significantly lower mean contact angles than controls (n = 124) without ulcer (57 degrees in duodenal ulcer, 59 degrees in gastric ulcer vs. 66 degrees in controls; p less than 0.0001). There was no change in contact angle after healing with H2-receptor antagonists by comparison with pretreatment (59 degrees vs. 56 degrees for duodenal ulcer, n = 15; 57 degrees vs. 59 degrees for gastric ulcer, n = 5). Controls with gastritis had lower contact angles than those without (61 degrees, n = 50, vs. 70 degrees, n = 63; p less than 0.0001). The presence of Campylobacter pylori was associated with a significant decrease in contact angle in controls (59 degrees, n = 39, vs. 70 degrees, n = 75; p less than 0.0001).
    Gastroenterology 06/1990; 98(5 Pt 1):1250-4. · 12.82 Impact Factor
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    ABSTRACT: A technique has been developed for assessing the surface hydrophobicity of human gastrointestinal mucosa by measuring the plateau contact angle of saline drops applied to endoscopic biopsy specimens. The plateau contact angle was not affected by the mode of drying. The intraobserver and interobserver coefficient of variation was less than 5%. The gastric mucosal surface had a higher mean contact angle than the submucosal surface (69 degrees vs. 47 degrees, p less than 0.001). Glycerol drops gave lower contact angles than saline drops (55 degrees vs. 69 degrees) but gave the same derived values for surface free energy (42 vs. 41 mJ/m2). Regional values for contact angle were as follows: gastric body 70 degrees, antrum 70 degrees, duodenal bulb 62 degrees (p less than 0.01 vs. stomach), distal duodenum 50 degrees (p less than 0.001 vs. stomach and p less than 0.01 vs. bulb), and rectum 57 degrees (p less than 0.001 vs. stomach). We conclude that it is feasible to measure the surface hydrophobicity of human endoscopic biopsy specimens and that the stomach is relatively more hydrophobic than the duodenum and rectum.
    Gastroenterology 08/1989; 97(1):104-11. · 12.82 Impact Factor