The aurate assessment of aximal gastric secretion in control subjects and patients with duodenal ulcer

Intra- and interindividual variability in fasted gastric content volume

BACKGROUND

Gastric fluid plays a key role in food digestion and drug dissolution, therefore, the amount of gastric fluid present in a fasted state may influence subsequent digestion and drug delivery. We aimed to describe intra- and interindividual variation in fasted gastric content volume (FGCV) and to determine the association with age, sex, and body size characteristics.

METHODS

Data from 24 MRI studies measuring FGCV in healthy, mostly young individuals after an overnight fast were pooled. The analysis included 366 participants who had up to 6 repeated measurements, with a total of 870 measurements. Linear mixed model analysis was performed to calculate intra- and interindividual variability and to assess the effects of age, sex, weight, height, weight*height as a proxy for body size, and body mass index (BMI).

RESULTS

FGCV ranged from 0 to 156 mL, with a mean (± SD) value of 33 ± 25 mL. The overall coefficient of variation within the study population was 75.6%, interindividual SD was 15 mL, and the intraindividual SD was 19 mL. Age, weight, height, weight*height, and BMI had no effect on FGCV. Women had lower volumes compared to men (MD: -6 mL), when corrected for the aforementioned factors.

CONCLUSION

FGCV is highly variable, with higher intraindividual compared to interindividual variability, indicating that FGCV is subject to day-to-day and within-day variation and is not a stable personal characteristic. This highlights the importance of considering FGCV when studying digestion and drug dissolution. Exact implications remain to be studied.

Epidermal growth factor in saliva and gastric juice: response to histamine

Epidermal growth factor (EGF) was measured in saliva and in gastric juice under basal conditions and after histamine stimulation (0.04 mg kg-1h-1). Sixty subjects studied comprised 20 normal volunteers, 20 patients with duodenal ulcer (DU), and 20 patients with non-ulcer dyspepsia (NUD). There was no difference in basal salivary EGF concentrations between control and DU or control and NUD subjects, but the EGF concentration in DU patients exceeded that in NUD patients (p < 0.05). Basal gastric juice concentrations of EGF were similar in all three groups. There was no difference between basal salivary and gastric EGF concentrations (p > > 0.05). After histamine stimulation, salivary and gastric EGF concentrations increased in all three groups: the increase was greater in gastric juice than saliva (p < 0.0001). There were no significant differences in the salivary EGF concentrations of controls and NUD patients, or controls and DU patients, but values were significantly higher when DU and NUD patients were compared (p = < 0.05). In the gastric juice, EGF increased more in DU patients than in controls or NUD patients (p < 0.05). This effect was not linked to the greater acid secretion in DU than in the other groups. There was no influence of gender or smoking on the EGF concentration. This evidence suggests that the stomach itself may be able to secrete large amounts of EGF and that histamine is a potent stimulus. It is more likely that the gastric EGF is responding to the presence of a duodenal ulcer than that lack of EGF is responsible for persistence of the ulcer.

Gastric juice epidermal growth factor concentration and Helicobacter pylori in patients with duodenal ulcer

The level of epidermal growth factor (EGF) was measured in the basal and maximally stimulated gastric juice of 20 control subjects and 20 patients each with duodenal ulcer and non-ulcer dyspepsia. Basal gastric juice was analysed for ammonia and urea concentrations, and the [ammonia]3/[urea] ratio was used to show Helicobacter pylori status, as was the [13C]urea breath test in nine controls. There was complete concordance in the nine controls between the two methods for determining H. pylori status. Twenty-five subjects were H. pylori positive (seven with duodenal ulcer, nine with non-ulcer dyspepsia, nine controls) and 35 H. pylori negative (13, 11 and 11 respectively). In H. pylori-positive subjects, the median EGF concentrations in the stimulated secretion of patients with duodenal ulcer and without (non-ulcer dyspepsia and controls combined) were 46.7 and 18.0 ng/ml (P < 0.001), and in H. pylori-negative subjects were 40.0 and 26.5 ng/ml respectively (P < 0.01). There was no difference in EGF concentration between controls and subjects with non-ulcer dyspepsia irrespective of H. pylori status. Lack of EGF is unlikely to be a cause of duodenal ulcer. The increased EGF concentration in patients with ulcer bore no relationship to the H. pylori status of the individual. If this bacterium causes duodenal ulcer, it is not via a reduction in EGF concentration.

Duodenal ulcer, Helicobacter pylori, and gastric secretion

Patients with chronic dyspepsia were categorised by macroscopic appearance at oesophagogastroduodenoscopy as having duodenal ulceration (DU), other diagnosed lesions such as reflux oesophagitis, carcinoma of stomach, etc, or no organic lesion (non-ulcer dyspepsia, NUD). Material was collected to identify gastric infection with Helicobacter pylori (H pylori) by CP urease test, culture, and histological examination and to make the microscopic diagnosis of active chronic gastritis. Each patient in the DU and NUD categories was then invited to volunteer for a gastric secretion study in which maximal gastric secretion in response to histamine was measured. Sixty two gastric secretion tests were performed (31 DU, 31 NUD). The presence of H pylori was associated with active chronic gastritis (100%). DU patients secreted more acid than the NUD patients. H pylori positivity was associated with decreased maximal gastric secretion in both groups. There was a positive correlation between smoking and maximal acid output shown only in H pylori negative but not in H pylori positive patients. These findings were clear cut when all corrections of maximal gastric secretion were made for pyloric loss, duodenogastric reflux, and stature. This study failed to show any aetiological link between H pylori and DU by increased maximal gastric secretion.

Lack of necessity for corrections for pyloric losses and duodenogastric reflux in the performance of gastric secretory studies

Gastric secretory studies are subject to considerable error owing to incomplete collections and to contamination by reflux of alkaline duodenal contents. Corrections for these sources of error have been defined, and they have been extensively applied in a research setting. In order to assess their utility in the performance of routine gastric secretory studies, the value of such corrections was assessed in 56 studies in patients with duodenal ulceration (10), previous surgical vagotomy (8), reflux oesophagitis (30) and primary oesophageal motility disorders (8). The effect of such corrections was small, and there were close correlations between uncorrected and corrected acid outputs in all four groups. The status of the vagal efferent gastric fibres was assessed by comparing the acid output after insulin hypoglycaemia with the maximal acid output after pentagastrin (insulin: pentagastrin ratio). The application of the corrections did not alter the conclusion regarding the assessment of vagal status in 55 of the 56 studies performed. It is concluded that such corrections are not necessary in the routine performance of gastric secretory studies.

Comparison of maximal gastric secretion in smokers and non-smokers with and without duodenal ulcer

Maximal gastric secretion was induced in 122 control subjects (without peptic ulcer) and 201 preoperative duodenal ulcer patients by intravenous histamine acid phosphate (130 nmol/kg/h), and measured as Vg (ml/h) and MAO (mmol/h). In both groups, men secreted more than women, and smokers secreted more than non-smokers. Significant correlations were found between maximal gastric secretion on the one hand, and height, age, and chronic smoking on the other. After standardisation for these factors, including standardisation to zero smoking, the subgroups of the controls no longer differed significantly, as was also the case for the duodenal ulcer patients. Thus, differences in height, age, and smoking habit were sufficient to account for the variation in maximal secretion between individuals in either the control or duodenal ulcer groups. Even after standardisation, however, the duodenal ulcer patients still secreted significantly more than the controls, and therefore, although chronic smoking has been shown to affect maximal gastric secretion, it does not appear to be the sole reason for hypersecretion in duodenal ulcer patients.

Maximal gastric secretion and duodenogastric reflux in patients with gastric or duodenal ulcer and in control subjects

Maximal gastric secretion was studied in 41 unoperated patients with gastric ulcer, 201 patients with duodenal ulcer, and 122 control subjects. The patients with a gastric ulcer were divided into high, body and prepyloric, according to the site of the ulcer. Both high and body gastric ulcers secreted significantly less than the controls, and the duodenal ulcer patients secreted significantly more. However, the patients with gastric ulcer were older and lighter than the controls and, since these factors are known to influence maximal gastric secretion, the controls and patients with duodenal ulcer were standardized to the mean weight (and age, for the controls) of the gastric ulcer group. After this standardization, there was no significant difference in secretion between the patients with body ulcers and normal controls. Pyloric loss was a similar percentage of maximal gastric secretion in all groups, but duodenogastric reflux was higher in the gastric ulcer group compared to the controls. The mean volume of duodenogastric reflux was greatest in the patients with a prepyloric gastric ulcer. It is commonly accepted that hyposecretion in patients with a gastric ulcer is due to gastritis consequent upon increased duodenogastric reflux. However, in this study, no gastric hyposecretion was evident in the body and prepyloric gastric ulcer groups, both of whom had greater than normal levels of duodenogastric reflux.

Maximal gastric secretion in smokers and non-smokers with duodenal ulcer

Sex, stature, age and smoking habits were investigated as possible determinants of maximal gastric secretion in pre-operative patients with duodenal ulcer. Stimulation was by an intravenous infusion of histamine (130 nmol kg-1 h-1) in 201 patients. Men were found to secrete significantly more than women, and smokers secreted significantly more than non-smokers. By multiple regression analysis, height and the total number of cigarettes smoked were found to be significant positive, and age significant negative factors in the magnitude of maximal gastric secretion. Upon standardization for these factors, the differences between the sexes and the smoking groups disappeared. It is suggested that, at least in men, chronic smoking increases maximal gastric secretion, and therefore could have a role in the aetiology of duodenal ulcer.

Thiocyanate as a marker of saliva in gastric juice?

One source of error in gastric secretion studies is swallowed saliva. The possibility that salivary thiocyanate might be used to measure this contamination has been investigated. Thiocyanate concentration was measured in saliva and gastric juice collected simultaneously in 22 duodenal ulcer patients undergoing routine insulin and histamine secretion studies. On stimulation, despite the increase in the rate of gastric secretion this was not matched by an appropriate fall in the concentration of thiocyanate in gastric juice. Moreover, in one-third of the gastric juice specimens, the thiocyanate concentration was greater than in the simultaneous samples of saliva. Thus, contrary to what has been claimed, thiocyanate is present not only in saliva but also in gastric juice. Therefore it cannot be used as a marker of salivary contamination. An adequate marker of this source of error has not yet been found.

Gastric secretion and basal gastrin concentration in bilharzial hepatic fibrosis

Gastric secretion and fasting plasma gastrin levels were investigated in 26 patients with bilharzial hepatic fibrosis and 26 controls. The groups did not differ in their basal secretion. When stimulated by intravenous infusion of histamine the maximal acid output in patients with bilharzial hepatic fibrosis was significantly less than in the control group. This was unlikely to be a result of neutralisation by reflux of alkaline duodenal contents as the volumes of reflux were not different from control subjects, but was compatible with a true reduction in gastric secretion as assessed by two-component hypothesis. Neither the lowered gastric acidity nor the liver damage in patients with bilharzial hepatic fibrosis correlated with circulating gastrin. The fasting levels of plasma gastrin in these patients were not different from controls. As in other liver diseases the cause of diminished gastric secretion remains unclear.

[Results of the therapy of the carcinoma of the breast by partial mastectomy evaluation after over 15 years (author's transl)]

Between 1950 and 1960, 118 partial mastectomies in the treatment of early breast cancer have been carried out in four different techniques with block dissection and radiotherapy. The 5-10-15 year survivals were compared to a similar selection of 217 patients with radical operations. No significant differences could be found between the 5 and 10 years survival rates, but the number of patients living longer than 15 years is much higher following radical operation chiefly in the cases with stage II. It is probably caused by the double frequency of local recidives following partial mastectomy, and after their treatment no patients survived to the 15th year. Partial mastectomy is no routine procedure. It is carried out when the patient refuses radical operation. The partial mastectomy should be the subject of a controlled clinical study.

Maximum acid output in duodenal ulcer patients with different length of history and controls without dyspepsia

Recent studies suggest a normal maximum acid secretion in duodenal ulcer patients with a history of less than three years, but an increase of secretion in those with longer history. The validity of this hypothesis was investigated in groups of patients with operatively verified duodenal ulcer and history for less than 3, 3--6, and 7--10 years. Each group, including 21 men and nine women, was compared to two male and one female group of age-matched controls without dyspepsia. In smaller groups of 16 men it was possible to compare age-matched groups from a population of 376 men with histories for up to 22 years. Finally, 11 men with an ulcer history of less than one year were compared to 11 controls. All subjects had measurements of MAO by the augmented histamine test. MAO was significantly higher in patients with a history less than one year and less than three years, respectively, compared to controls. After correction of MAO for weight or lean body mass the difference remained significant in men, but not in the smaller groups of women. MAO in men with a history of from less than three up to 22 years did not show any maximum. Thus, the study did not support the assumption that gastric hypersecretion is a result of duodenal ulceration.

Hypersecretion and length of history in duodenal ulceration

Maximal gastric secretion, measured by the histamine-infusion test, was, as expected, significantly greater in a group of 81 patients with duodenal ulcer than in a group of 72 controls. After standardising for the effect of stature on maximal secretion, only 24 of the patients were found to be true hypersecretors. However, maximal secretion in the ulcer group increased with length of history of symptoms, and extrapolation back to zero length of history suggested that there was no significant hypersecretion at that time. These facts support the hypothesis that it is the presence of the ulcer that leads to hypersecretion rather than the converse. Possible mechanisms involved are chronic ingestion of antacids to counter dyspepsia, or gastric distension due to pylorospasm.

Maximal gastric secretion in patients with chronic airway obstruction

It has been suggested that patients with chronic obstructive chest disease have greater maximal gastric secretion than normal subjects. This problem was studied in 30 subjects using the histamine infusion test with phenol red as a marker to correct for pyloric loss. Clinical, radiological, and physiological criteria were used to define two groups: (1) 13 subjects with normal chests; (2) 14 subjects with unequivocal chronic airway obstruction.

The two groups did not differ significantly in maximal gastric secretion, and this conclusion was not altered by taking stature into account because stature was statistically comparable in the two groups. However, age was significantly different and correction of the secretory data for the diminution of maximal secretion with age improved the correspondence between the groups.

The failure to take stature and age into account may be responsible for conflicting evidence in the past.