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J A Drapers

Publications and source records attributed to J A Drapers.

8 recordsLinked to original sources
PubMed1990

[The course of benign stomach ulcer; results of a follow-up study].

A follow-up investigation was conducted in 112 patients in whom a benign gastric ulcer had been found endoscopically between 1978 and 1984. Nine patients had been operated upon, mainly in the earlier years. Out of 65 patients ultimately selected for the study 38 underwent gastroscopy and 35 could be evaluated. Of these 21 (60%) had complaints and another 60% used intermittent or continuous medication because of complaints referred to the stomach. In 15 patients erosions (4) or benign gastric ulcers (11) were found. In all patients in whom it was looked for Campylobacter pylori was found in the gastric mucosa. The benign gastric ulcer is a chronic, recurrent affection. We did not find a large proportion of asymptomatic recurrent ulcers. Many patients continue to use drugs. The complaints in patients with mucosal lesions are often atypical.

Adult↗
PubMed1990

Isolation of a potent cholesterol nucleation-promoting activity from human gallbladder bile: role in the pathogenesis of gallstone disease.

Gallbladder bile contains nucleation-promoting activity that binds to concanavalin A. The activity was found in gallbladder bile from cholesterol gallstone patients but also in gallbladder bile from patients without stones and patients with pigment stones. Bile from patients with multiple cholesterol gallstones contained high concanavalin A-binding nucleation-promoting activity. The activity was much lower in bile samples from pigment stone patients, patients without stones and patients with a solitary cholesterol stone. Serum contained very little activity and no concanavalin A-binding nucleation-promoting activity could be demonstrated in gallbladder mucosa. This suggests that concanavalin A-binding nucleation promoter is produced in the liver or bile duct epithelium. The activity was fully resistant to digestion with pronase but was heat labile and could be destroyed by prolonged incubation with a mixed glycosidase preparation indicating that sugar residues are important for this activity. On a Superose 12 gel permeation column, promoting activity eluted in two major peaks at apparent molecular weights of 150 +/- 30 kD (n = 5) and less than 5 kD respectively. The mobility on the column was not influenced by pronase digestion. The factor with the higher molecular weight could be isolated further by polyacrylamide gel electrophoresis under nondenaturing conditions. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the apparent molecular weight of the glycoprotein was 130 kD. In conclusion, gallbladder bile contains nucleation-promoting activity that binds to concanavalin A. The activity is increased in bile from patients with multiple cholesterol gallstones and could therefore play an important role in the pathogenesis of gallstone disease.

Bile↗
PubMed1989

An appraisal of the role of biliary phospholipases in the pathogenesis of gallstone disease.

Human bile contains proteins that influence nucleation of cholesterol. Recently, it has been suggested that activity of phospholipases in bile may play a role in this process. To study the influence of phospholipase on nucleation we have determined the effect of phospholipases A2, C and D on the nucleation time of model bile. Phospholipase C decreased the nucleation time, whereas phospholipase A2 inhibited nucleation. The phospholipases were effective only at relatively high concentrations. Phospholipase D was strongly inhibited in model bile and probably only influenced the nucleation time by an aspecific protein effect. The cleavage products of the different phospholipases were determined in native bile samples of 14 cholesterol gallstone patients, 6 patients without stones and 4 patients with pigment stones. In all samples, choline, phosphorylcholine and free fatty acids (FFA) could be detected. However, there was no significant difference between the three groups of patients. The rate of production of choline, phosphorylcholine and FFA was measured in bile incubated at 37 degrees C. Again, there was no significant difference between the three groups of patients. We conclude that phospholipase activity in bile does not play an important role in the pathogenesis of gallstone disease.

Bile↗
PubMed1987

Quantification of cholesterol nucleation promoting activity in human gallbladder bile.

We have developed a simple method to quantitate cholesterol nucleation promoting activity in bile. The method makes use of the fact that gallbladder bile of cholesterol gallstone patients contains potent nucleation promoting activity. Gallbladder bile samples were serially diluted, routinely from 1/25 to 1/6,400. The diluted samples were mixed with a supersaturated model bile and the nucleation time (NT) of the mixtures was determined. The greatest dilution that resulted in a significant shortening of the NT was called the nucleation promoting activity titre (NPAT). The determination is independent of the original lipid content of the bile sample. The NPAT was measured in 14 gallbladder bile samples derived from patients with cholesterol gallstones and 9 controls. In all samples promoting activity was found. In the samples from the stone patients the NPAT was significantly elevated as compared to the patients without cholesterol stones (p = 0.01). Our results suggest that the cholesterol saturation index and the activity of cholesterol nucleation promoting factors are the most important factors in the pathogenesis of cholesterol gallstone disease. Assessment of the NPAT allows the differentiation of groups of patients with a normal cholesterol saturation index who are at risk for gallstone formation due to a high NPAT.

Bile↗
PubMedDate not supplied

Cholesterol nucleation-influencing activity in T-tube bile.

Nucleation-influencing activity was determined in T-tube bile samples derived from patients with obstructive jaundice. Since native T-tube bile samples do not nucleate, nucleation-influencing activity was determined by measuring the influence of T-tube bile on the nucleation time of model bile. In the assay, T-tube bile was mixed with model bile, and the nucleation time of this mixture was compared with the nucleation time of a model bile supplemented with the same amount of lipid as present in the bile sample. The results were expressed as ratio of the nucleation time of the mixture and the nucleation time of the control (NTm/NTc). There was a significant difference (p less than 0.01) between bile samples from patients with cholesterol gallstones and samples from patients with biliary obstruction due to other causes. More than 80% of the 33 samples from eight patients with stones were nucleation-promoting (NTm/NTc less than or equal to 0.6). Of the 40 bile samples from patients without stones, 7 were nucleation-promoting, 25 had no effect (NTm/NTc = 0.8 to 1.2) and 8 bile samples were nucleation-inhibiting (NTm/NTc greater than or equal to 1.4). There was no correlation between the lipid or protein content of a T-tube bile sample and its nucleation-influencing activity. The presence of both nucleation-promoting and nucleation-inhibiting activity in the same T-tube bile was demonstrated by chromatography on concanavalin A-Sepharose. More than 75% of the biliary protein did not bind to the column. This fraction showed nucleation-inhibiting activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile↗