Showing papers by "Jane M. Andrews published in 1997"

Effects of small intestinal nutrient infusion on appetite and pyloric motility are modified by age

Abstract: The mechanisms responsible for the reduction in appetite and slowing of gastric emptying in older persons are unknown. The aims of this study were to evaluate the effects of aging on small intestinal regulation of appetite and pyloric motility. Eight healthy older (age 65-75 yr) and seven healthy young (age 20-34 yr) male subjects received isocaloric (2.9 kcal/min) intraduodenal infusions of lipid and glucose for 120 min, each on separate days. During the intraduodenal infusions, perceptions of hunger, desire to eat, and fullness were assessed by visual analog scales. Pyloric motility (isolated pyloric pressure waves and tonic pyloric pressure) was measured by manometry during the intraduodenal lipid infusion. On each day, after completion of the intraduodenal nutrient infusion the subject was offered a buffet meal and food intake was quantified. Before intraduodenal nutrient infusions, sensations of hunger (P < 0.01) and desire to eat (P < 0.05) were less in the older compared with the young subjects. In the young, intraduodenal lipid suppressed hunger to a greater extent than intraduodenal glucose (P < 0.05). In older persons, neither intraduodenal nutrient infusion suppressed hunger. Intraduodenal lipid and glucose increased fullness in both age groups (P < 0.05 for both), with no significant difference between the two nutrients. There was no significant difference in food intake from the buffet meal between the elderly and young subjects. Intraduodenal lipid infusion stimulated phasic pyloric pressure waves in both age groups (P < 0.01 for both), and this response was greater (P < 0.05) in older persons. There was an increase (P < 0.01) in tonic pyloric pressure during intraduodenal lipid infusion that was not significantly different between the two age groups. We conclude that the effect of small intestinal lipid infusion on hunger is attenuated, and the stimulation of phasic pyloric pressure waves increased in healthy older persons compared with healthy young males. Increased feedback from small intestinal nutrients does not appear to be responsible for the physiological anorexia of aging.

Altered expression of mucins throughout the colon in ulcerative colitis.

Abstract: BACKGROUND/AIMS: Regional differences in the biology of the colonic epithelium may determine the extent of involvement by ulcerative colitis. Novel monoclonal antibodies (MAbs) were used in this study to investigate regional heterogeneity in the colonic mucosa. METHODS: MAbs generated using a method of tolerisation against common antigens in the proximal colon and distal colon were used for immunoperoxidase staining, comparative histochemistry, immunoblotting, and slot-blot analysis. RESULTS: The colon specific MAbs 5F1 (IgG3) and 6G4 (IgM) stained goblet cell contents throughout the normal distal colon but staining was markedly reduced in the proximal colon (p < 0.0001). In the distal colon of patients with ulcerative colitis, whether quiescent or actively inflamed, reactivity was reduced compared with controls (p < 0.05, p < 0.001 respectively). By contrast, an overall increase in staining was seen in the uninflamed proximal colon in ulcerative colitis compared with controls (p < 0.02). Comparative staining with high iron diamine and biochemical analyses indicated that MAb 6G4 was reactive with mucin bearing sulphate or O-acetylated sialic acid groups, or both. CONCLUSIONS: Regional differences in the staining characteristics of normal colonic mucin have been shown using novel monoclonal antibodies. The pattern of mucin expression throughout the colon in ulcerative colitis is altered even in the absence of histological changes.

Acute hyperglycaemia affects anorectal motor and sensory function in normal subjects

Abstract: Background—The pathogenesis of anorectal dysfunction, which occurs frequently in patients with diabetes mellitus, is poorly defined. Recent studies indicate that changes in the blood glucose concentration have a major reversible effect on gastrointestinal motor function. Aims—To determine the effects of physiological changes in blood glucose and hyperglycaemia on anorectal motor and sensory function in normal subjects. Subjects—In eight normal subjects measurements of anorectal motility and sensation were performed on separate days while blood glucose concentrations were stabilised at 4, 8, and 12 mmol/l. Methods—Anorectal motor and sensory function was measured using a sleeve/sidehole catheter incorporating a balloon, and electromyography. Results—The number of spontaneous anal relaxations was greater at 12 mmol/l than at 8 and 4 mmol/l glucose (p<0.05 for both). Anal squeeze pressures were less at a blood glucose of 12 mmol/l when compared with 8 and 4 mmol/l (p<0.05 for both). During rectal distension, residual anal pressures were not significantly different between the three blood glucose concentrations. Rectal compliance was greater (p<0.05) at a blood glucose of 12 mmol/l when compared with 4 mmol/l. The threshold volume for initial perception of rectal distension was less at 12 mmol/l when compared with 4 mmol/l (40 (20-100) ml versus 10 (10-150) ml, p<0.05). Conclusions—An acute elevation of blood glucose to 12 mmol/l inhibits internal and external anal sphincter function and increases rectal sensitivity in normal subjects. In contrast, physiological changes in blood glucose do not have a significant effect on anorectal motor and sensory function. Keywords: hyperglycaemia; anorectum; motility; sensation; diabetes mellitus

Hyperglycemia Affects Gastric Electrical Rhythm and Nausea During Intraduodenal Triglyceride Infusion

Abstract: Hyperglycemia slows gastric emptying andincreases the intensity of perception of gastricdistension during fasting and small intestinal nutrientstimulation. In order to examine the possibility thatabnormalities of gastric electrical rhythm may be associatedwith the effects of hyperglycemia, the gastricelectrical rhythm (cutaneous electrogastrogram) and theperception rating scores for upper gastrointestinal sensations (visual analog scale) were examined.Studies were performed during intraduodenal triglycerideinfusion in 10 healthy volunteers under euglycemic andhyperglycemic (≈15 mmol/liter) conditions. During fasting, hyperglycemia had no effect oneither gastric electrical rhythm or sensation.Intraduodenal triglyceride infusion was associated withan increase in bradygastria ( 3.6 cpm) wasmore prevalent during hyperglycemia when compared toeuglycemia (25 ± 10% vs 1 ± 1%, P <0.05) and the perception rating scores for nausea andabdominal discomfort were greater during hyperglycemia(P < 0.05 for both). The intensity of nauseacorrelated with the proportion of time spent in tachygastria (r = 0.64, P < 0.01).These data are consistent with the concept thatpostprandial upper gastrointestinal symptoms in patientswith diabetes mellitus may be modulated by the bloodglucose concentration.