Search PubMed⌕ Search

Biomedical subjects

H Koop

Publications and source records attributed to H Koop.

At least 55 records · Page 3Linked to original sources
PubMed1992

Healing and relapse of duodenal ulcer during ranitidine therapy in the elderly. The RUDER Study Group.

A total of 2,109 outpatients with active duodenal ulcer (DU) entered an open, prospective study in order to investigate factors influencing healing and relapse during 2 years of ranitidine therapy (300 mg daily for healing, 150 mg as maintenance treatment). In a retrospective analysis, we evaluated the influence of age. Symptoms related to DU in 1,899 evaluable cases in patients over 65 years of age (n = 185) were identical to those of DU patients younger than 65 years old (n = 1,714). Rapid healing within 2 weeks of ranitidine therapy was less frequent in the elderly (32.5%) than in younger patients (40.7%) though identical healing rates (94.1%) in each group were achieved by continuation of ranitidine therapy for 8 weeks. Cumulative recurrence rates during the 2 years of long-term therapy were lower (17.3%) in old age than in patients under 65 years of age (23.3%). Adverse events were rare in both age groups. We conclude that DU healing during ranitidine is delayed in old age. Additional differences in relapse rates in favor of the elderly suggest that DU disease has a different course in the elderly.

Adult↗
PubMed1992

Review article: metabolic consequences of long-term inhibition of acid secretion by omeprazole.

Metabolic sequelae of profound and long-lasting inhibition of gastric acid secretion by omeprazole have largely been neglected. Data from long-term studies suggest that vitamin B12 stores decrease slightly over several years, although this was not clinically relevant within the first 4 years of therapy. Additionally, it cannot be completely ruled out that patients with an increased iron demand may develop iron deficiency, but data available at present do not provide any evidence that iron malabsorption is to be expected under normal conditions. Protein homeostasis and calcium metabolism seem to be unaffected by long-term omeprazole therapy. Based upon present experience, serum cobalamin concentration should be monitored in patients undergoing omeprazole therapy for several years.

Absorption↗
PubMed1992

Effect of gastrin receptor antagonists on gastric acid secretion and gastrin and somatostatin release in the rat stomach.

The effects of two recently developed gastrin receptor antagonists, PD 136450 and L-365,260, on pentagastrin-stimulated acid secretion were investigated in rats. PD 136450 at a dose of 6 mg/kg s.c. (9.6 mumol) completely abolished acid secretion induced by pentagastrin. The inhibition of 18 mg/kg PD 136450 s.c. lasted for at least 8 h and was still effective after 14 days of treatment (18 mg/kg s.c. every 8 h). Acute application of L-365,260 at a dose of 3.8 mg/kg, which is equimolar (9.6 mumol) to 6 mg/kg PD 136450 reduced acid responses slightly. However, when L-365,260 was administered intravenously at a dose of 3 mg/kg, this antagonist completely abolished the pentagastrin-stimulated acid secretion. Furthermore, the effect of PD 136450 on endogenous gastric somatostatin and gastrin releases was tested in the isolated, vascularly perfused rat stomach. PD 136450 perfused at a concentration of 1 microM slightly increased somatostatin secretion after stimulation with a high dose of isoproterenol (10(-7) M). There was no effect of PD 136450 on basal or acetylcholine-stimulated gastrin secretion.

Animals↗
PubMed1992

Adaptation and renewal of the endocrine stomach.

At present at least seven different endocrine cell types have been identified in the stomach. According to their relative frequency and secretion products the antral gastrin producing G cell and somatostatin producing D cell and the fundic histamine producing ECL cell are the best characterized cell types. Total endocrine cell mass is controlled by various factors from inside and outside the stomach. Density of antral G and D cells depends on the presence and absence of food, on the antral pH and on additional humoral and/or neural factors. Gastrin and not gastric pH has been identified as the most important factor regulating the density of fundic ECL cells. Adaptation of gastric endocrine cells to gastric pH and to the presence, abundance or absence of humoral and neural regulators are well known phenomena though only partially understood. Antral G cells increase and antral D cells decrease during long-term achlorhydria which as a consequence leads to hypergastrinaemia. Examples are pernicious anaemia in man and drug-induced acid suppression under experimental conditions. Interestingly, achlorhydria-induced G cell hyperplasia never progresses to gastrinomas. Fundic ECL cell density increases markedly in the presence of long-lasting hypergastrinaemia independently of gastric pH. In contrast to G cells ECL cell hyperplasia may progress to rarely occurring ECLomas. However, this depends on additional conditioning factors as the presence of severe atrophic gastritis as in pernicious anaemia or a specific genetic trait present in patients with gastrinomas associated with the MEN I syndrome.

Adaptation, Physiological↗
PubMed1991

[Conservative treatment of florid peptic esophageal stenosis. Complete elimination by dilatation and omeprazole in H2-blocker refractory cases].

23 patients with severe reflux oesophagitis complicated by peptic erosive strictures requiring dilatation and resistant to H2-blocker therapy were treated with the proton pump inhibitor omeprazole (initial dosing: 40 mg daily) and dilated. Combination of dilatations (median 2, range 1 to 12 courses) and omeprazole therapy facilitated complete resolution of strictures and disappearance of peptic lesions after four and eight weeks in 30% and 70%, respectively. In all remaining cases healing could be achieved by perpetuation of omeprazole therapy though three patients (13%) required omeprazole doses higher than 40 mg daily for healing and maintenance. Follow-up investigations available in 17 patients during continuation of omeprazole therapy revealed no recurrence of strictures. It is concluded that more pronounced and particularly longer lasting inhibition of acid secretion is effective even in these most severe cases of reflux oesophagitis.

Adolescent↗
PubMed1991

Role of cholecystokinin in the control of gastric somatostatin in the rat: in vivo and in vitro studies.

Cholecystokinin (CCK) has been shown to be a powerful stimulus for somatostatin release from isolated canine fundic D-cells in short-term culture. The influence of the CCK analogue caerulein on the secretory activity of the D-cell in the intact stomach in vitro and the effect of elevated plasma levels of endogenous CCK on gastric somatostatin stores in vivo were investigated in the rat. Basal somatostatin secretion from the isolated, vascularly perfused rat stomach preparation was not affected by various doses of caerulein. Slight stimulation of somatostatin-like immunoreactivity (SLI) release by epinephrine was significantly inhibited by caerulein, whereas caerulein did not alter half-maximal stimulation of SLI secretion by isoproterenol. Rats with chronically elevated plasma CCK levels induced by experimental exocrine pancreatic insufficiency did not show any change in tissue concentrations of SLI or in D-cell number, both in the antrum and corpus. These data suggest that CCK--in contrast to dogs--is not an important modulator of gastric somatostatin in the rat.

Animals↗
PubMed1991

Dissociation of cholecystokinin and pancreaticobiliary response to intraduodenal bile acids and cholestyramine in humans.

The role of intraduodenal bile acids in the regulation of cholecystokinin (CCK), pancreatic polypeptide (PP), and secretin as well as exocrine pancreatic and biliary secretion was investigated by means of a duodenal marker perfusion technique in volunteers. The following solutions were perfused: (1) liquid test meal, (2) test meal with 6 g cholestyramine, (3) test meal with 2 g chenodeoxycholic acid (CDC), (4) test meal with 6 g cholestyramine and 2 g CDC, (5) 6 g cholestyramine alone, and (6) 2 g CDC alone. The test meal caused an immediate increase in CCK and PP plasma levels, whereas secretin was not significantly altered. CCK release was further enhanced by addition of cholestyramine, whereas CDC inhibited release. The stimulatory effect of cholestyramine was abolished by CDC. CDC alone and in combination with the test meal stimulated secretin release. The response of PP to the test meal was not altered by addition of either compound. Cholestyramine and CDC alone caused only a very small increase in CCK levels, whereas PP was stimulated to nearly postprandial values. Meal-stimulated pancreatic and biliary secretion was significantly enhanced by cholestyramine, CDC, and the combination of both. CDC and cholestyramine alone each stimulated enzyme and bile secretion to a greater extent than the test meal. We conclude that intraduodenal bile salts are a modulator of postprandial CCK release. Changes in exocrine pancreatic and biliary and PP secretion do not necessarily parallel CCK concentrations, suggesting that different mediators are involved in the observed bile acid-induced changes in humans.

Adult↗
PubMed1991

Long-term maintenance treatment of reflux esophagitis with omeprazole. Prospective study in patients with H2-blocker-resistant esophagitis.

Thirty-four patients with H2-blocker-resistant reflux esophagitis subsequently healed by 40 mg omeprazole daily entered a maintenance study with 20 mg omeprazole. In 31 evaluable cases the observation period was at least 12 months (mean 24 months). Esophagitis remained in remission in two thirds of patients despite dose reduction. Relapses of esophagitis occurred in 10 cases within six months, which rapidly healed by increasing the omeprazole dose to 40 mg. No further recurrence with 20 mg omeprazole was found later than six months. Peptic strictures primarily requiring repeated dilatation in six patients during healing with omeprazole did not reappear while on omeprazole maintenance. Major side effects that could be attributed to omeprazole were not observed. Gastrin levels remained within or slightly above the normal range in the vast majority. It is concluded that omeprazole maintenance treatment in severe reflux esophagitis is an effective and safe therapy.

Adult↗
PubMed1991

Proliferation of endocrine cells in the rat stomach caused by drug-induced achlorhydria.

Time-related changes of serum gastrin levels, gastrin cell, and enterochromaffinlike cell densities, and proliferation kinetics of these cells have been examined in rats during treatment with the substituted benzimidazole BY 308 over a period of 73 days. Serum gastrin levels increased very rapidly from 74 +/- 6 pg/mL (controls) to 438 +/- 31 pg/mL (day 1) and 727 +/- 68 pg/mL (day 4). Thereafter, a steady increase was observed until day 70 (2097 +/- 208 pg/mL). Enterochromaffinlike cell density was unchanged until day 10, but then increased progressively without reaching a plateau (144% above control on day 73). The labeling index of these cells was enhanced shortly after drug application and remained on a constant elevated level from day 14 to day 73 (about 10-fold to 12-fold above controls from day 14 to day 70). The number of gastrin cells increased rapidly within the first week and reached a plateau after 17 days (96% increase above controls). In contrast to enterochromaffinlike cells, the labeling index did not change immediately but increased on day 7 by 37% and returned beneath control values after day 28. The results suggest that in drug-induced achlorhydria, the progressive increase of enterochromaffinlike cells is explained by an enhanced mitosis, whereas other factors in addition to proliferation are responsible for the augmentation of gastrin cells.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1991

Antral Helicobacter pylori-like organisms in different states of gastric acid secretion.

The frequency of Helicobacter pylori (H.p.) infestation in antral mucosa and the presence of gastritis were investigated in different states of gastric acid secretion. Biopsies were stained by the Warthin-Starry technique and hematoxylin-eosin. Antral H.p. was found in similar frequencies in Zollinger-Ellison syndrome (n = 17; profound acid hypersecretion, associated with duodenal ulcer disease in most cases) and the same number of age-matched controls (35% in each group) whereas H.p. could be detected in 31 out of 33 duodenal ulcer patients (94%). The incidence of H.p. infestation in H2-blocker refractory reflux oesophagitis was low (24%). Treatment of peptic lesions with omeprazole (drug-induced hypochlorhydria) led to a reduction or disappearance of H.p. in 7 out of 10 H.p.-positive patients whereas none of 19 primarily H.p.-negative patients became infected with H.p. during prolonged omeprazole therapy. It is concluded that (1) development of duodenal ulcers (as in gastrinomas) does not necessarily require H.p., and (2) at least in some patients H.p. is reduced in antral mucosa by omeprazole.

Adolescent↗
PubMed1991

[Reduction of gastric acid secretion: pathophysiologic and clinically relevant sequelae].

After proton pump inhibitors (omeprazole) became available, discussions about safety aspects of (particularly long-term) inhibition of gastric acid secretion have been renewed. In contrast to animals, hypergastrinaemia does not seem to be a relevant problem in man: marginal increases of serum gastrin during proton pump inhibition may induce proliferation of gastric endocrine ("enterochromaffin-like"; ECL-) cells in some cases which are without clinical importance, the risk for development of gastric carcinoids seems negligible if existent at all. Other aspects of acid inhibition (e.g. protein malabsorption, diminished iron and cobalamin absorption, bacterial overgrowth of the stomach, risk of gastric cancer) do also not appear to be of clinical relevance. However, data from larger numbers of patients on long-term therapy with proton pump inhibitors should be available until such treatment can be generally recommended.

Animals↗
PubMed1990

Correlation of pancreatic enzyme levels with the patient's recovery from acute edematous pancreatitis.

Levels of total amylase, pancreatic isoamylase, lipase and immunoreactive trypsin were measured in 27 consecutive patients with noncomplicated (methemalbumin negative, no pseudocysts on ultrasound) acute pancreatitis during the acute, subacute, and recovery phases. At the beginning of the recovery phase (no pain, start of oral food intake), amylase and pancreatic isoamylase were below normal, whereas lipase (12% of the patients) and especially trypsin (52% of the patients) were still three times above the upper limit of normal. None of the patients showed a relapse of pain at the time of oral food intake. The conclusion is that amylase and pancreatic isoamylase reflect more accurately the patient's recovery pattern in acute pancreatitis than the other enzymes. Trypsin, however, may be significant in cases of delayed diagnosis. Thus, the decision to start oral food intake should be based on the patient's clinical state rather than on pancreatic enzyme levels.

Acute Disease↗
PubMed1990

Serum gastrin levels during long-term omeprazole treatment.

Serum gastrin was determined in 33 patients during treatment with the proton pump inhibitor omeprazole. After 4 weeks of therapy, gastrin levels increased to a median of 55 pg/ml compared to 15 pg/ml prior to omeprazole (P less than 0.001). There was a close correlation (r = 0.939; P less than 0.001) between pre-treatment gastrin and levels at 4 weeks. Comparison of serum gastrin concentrations at 1 month of omeprazole with levels at 6 (n = 21) and 12 months (n = 12) continuous therapy revealed a close correlation (r = 0.961 and r = 0.882, respectively; P less than 0.001) despite dose adjustment. In marked hypochlorhydria documented by continuous pH monitoring, serum gastrin varied from normal up to profound hypergastrinaemia. These results demonstrate that the serum gastrin increase under powerful acid-inhibitory drug therapy depends upon a number of variables. (a) Only in patients with elevated gastrin levels, prior to omeprazole treatment, can moderate to marked hypergastrinaemia during omeprazole be expected. (b) Gastrin increases reached during the initial period of omeprazole treatment remain constant during long-term therapy. (c) Acid inhibition itself is not necessarily associated with an increase in serum gastrin in every patient, which suggests that the individual sensitivity of the gastrin cell to acid inhibition is more important for serum gastrin changes than the degree of acid inhibition itself.

Esophagitis, Peptic↗
PubMed1990

Prospective evaluation of omeprazole treatment in reflux oesophagitis refractory to H2-receptor antagonists.

The efficacy of omeprazole therapy (40 mg daily) in H2-blocker refractory severe reflux oesophagitis (Grade II-IV; Savary and Miller classification) was investigated in 61 patients. Mean duration of reflux disease and preceding H2-antagonist treatment were 4.3 years and 15 months, respectively. Healing rates at 4, 8 and 12 weeks were 48%, 80% and 92%, respectively. There was a correlation between severity of oesophagitis and duration of omeprazole therapy necessary for healing. Three patients (5%) required higher dosages than 40 mg for healing. Symptomatic responses paralleled healing. It is concluded that omeprazole is a highly effective drug for severe reflux oesophagitis not responding to H2-blocker treatment and that 40 mg daily is the optimal dose.

Adolescent↗