Eiliv Brenna

The Predictive Value of History in Dyspepsia

Symptomatic patients referred to an open-access upper gastrointestinal endoscopy completed a detailed, self-administered questionnaire aimed at assessing the predictive value of history in dyspepsia. Nine hundred and thirty patients were suitable for analysis. Of these, 29% were found to have organic dyspepsia. A substantial overlap of symptoms and demographic data was found among the various endoscopic diagnoses. Discriminating variables were identified by stepwise logistic regression analysis and included in predictive score models. Pain relieved by antacids, age above 40 years, previous peptic ulcer disease, male sex, symptoms provoked by berries, and night pain relieved by antacids and food were found to predict organic dyspepsia with a sensitivity and specificity of approximately 70%, when applied on the observed material. Similar probabilities were found for score models of peptic ulcer and esophagitis. In general, the low prevalence of organic diseases resulted in low positive and high negative predictive values. Accordingly, the main impact of the predictive models may be to reduce the number of negative endoscopies rather than to predict a precise diagnosis. Independent of disease category and age, 41% of the subjects expressed a fear of malignancy, emphasizing the value of reassurance from a negative endoscopy.

Classification of tumours

Tumours are classified according to the most differentiated cells with the exception of carcinomas where a few tumour cells show neuroendocrine differentiation. In this case these cells are regarded as redifferentiated tumour cells, and the tumour is not classified as neuroendocrine. However, it is now clear that normal neuroendocrine cells can divide, and that continuous stimulation of such cells results in tumour formation, which during time becomes increasingly malignant. To understand tumourigenesis, it is of utmost importance to recognize the cell of origin of the tumour since knowledge of the growth regulation of that cell may give information about development and thus possible prevention and prophylaxis of the tumour. It may also have implications for the treatment. The successful treatment of gastrointestinal stromal tumours by a tyrosine kinase inhibitor is an example of the importance of a correct cellular classification of a tumour. In the future tumours should not just be classified as for instance adenocarcinomas of an organ, but more precisely as a carcinoma originating from a certain cell type of that organ.

Neuroendocrine Differentiation in Human Gastric Carcinoma

Distinguishing between neuroendocrine carcinoma and adenocarcinoma may be difficult.

Long-term effects of inhaled nicotine

Tobacco smoking has been reported to be associated with increased risk of cardiovascular disease and cancer, particularly of the lungs. In spite of extensive research on the health effects of tobacco smoking, the substances in tobacco smoke exerting these negative health effects are not completely known. Nicotine is the substance giving the subjective pleasure of smoking as well as inducing addiction. For the first time we report the effect on the rat of long-term (two years) inhalation of nicotine. The rats breathed in a chamber with nicotine at a concentration giving twice the plasma concentration found in heavy smokers. Nicotine was given for 20 h a day, five days a week during a two-year period. We could not find any increase in mortality, in atherosclerosis or frequency of tumors in these rats compared with controls. Particularly, there was no microscopic or macroscopic lung tumors nor any increase in pulmonary neuroendocrine cells. Throughout the study, however, the body weight of the nicotine exposed rats was reduced as compared with controls. In conclusion, our study does not indicate any harmful effect of nicotine when given in its pure form by inhalation.

Review article: the pharmacological inhibition of gastric acid secretion—tolerance and rebound

During the last decade our understanding of the regulation of gastric acid secretion has changed considerably. The recognition that gastrin acts mainly by releasing histamine from the enterochromaffin‐like (ECL) cell is of major importance. It is now necessary to review and seek new explanations for the development of tolerance and for the post‐treatment acid hypersecretion that may be observed when treatment with acid‐secretory inhibitors is discontinued. Tolerance and rebound related to H2‐receptor antagonists has previously been explained as upregulation of gastrin and/or histamine H2‐receptors, and/or an increased parietal cell mass. Experimental evidence for these theories is scarce. On the other hand, tolerance can now be explained by a gastrin‐induced increase in ECL cell‐derived histamine at the parietal cell H2‐receptor competing with the antagonist. The lack of tolerance to proton pump inhibitors may be explained by their mode of action, being non‐competitive and acting at the H+, K+‐ATPase rather than at stimulatory receptors. Post‐treatment rebound acid hypersecretion can be understood as gastrin upregulating and/or stimulating growth of the ECL cell, leading to increased amounts of releasable histamine post‐treatment. Novel experimental data strongly support this view of the development of tolerance and post‐treatment rebound acid hypersecretion.

Relationship between Endoscopic Hiatus Hernia and Gastroesophageal Reflux Symptoms

Little is known about the relationship between hiatus hernia (HH) and gastroesophageal reflux symptoms (GERS). Nine hundred and thirty patients submitted to gastroscopy because of symptoms completed a self-administered questionnaire. Fourteen per cent showed esophagitis (ES) and 17% HH. Forty-nine per cent of the patients with HH had endoscopic ES, and 60% of those with ES had HH. The severity of ES was dependent (p less than 0.05) on both the presence and the size of HH. After exclusion of patients with peptic ulcer and malignancy, patients with and without HH and ES were compared with regard to the presence of single symptoms and a weighted GERS score based on symptoms proven to be typical for ES. Only borderline differences were found between patients with ES and HH and those with ES and no HH. The former group, however, presented with significantly (p less than 0.001) more GERS than the patients with HH only. Nevertheless, the patients with HH as the only pathologic finding had significantly (p less than 0.01) more GERS than the patients with no major endoscopic abnormality. This study indicates a close association between HH and gastroesophageal reflux disease and supports the clinical significance of an endoscopically detected HH.

Detection of chromogranin A in human gastric adenocarcinomas using a sensitive immunohistochemical technique.

Neuroendocrine cells are often disclosed in human gastric adenocarcinomas and may be recognised by their immunoreactivity towards chromogranin A. However, in dedifferentiated neuroendocrine tumour cells, the chromogranin A content may be reduced making it difficult to detect with conventional immunohistochemical methods. We therefore used a sensitive signal amplification technique in order to evaluate chromogranin A immunoreactivity and thus neuroendocrine differentiation in 40 gastric adenocarcinomas.Neuroendocrine cells were visualised by means of a monoclonal chromogranin A antibody and the avidin–biotin peroxidase complex technique, without and with addition of tyramide signal amplification. Double immunohistochemistry towards chromogranin A and Ki-67 were used to disclose proliferation in the neoplastic cells.A marked increase in the number of carcinomas containing chromogranin A-immunoreactive neoplastic cells was noted when applying the tyramide signal amplification technique. In addition, the number of immunoreactive cells within each tumour increased, and in some cases almost all the neoplastic cells became immunoreactive. Chromogranin A-immunoreactive tumour cells showing signs of proliferation were found in the majority of these carcinomas.In conclusion, we have disclosed widespread immunoreactivity towards chromogranin A in a proportion of gastric adenocarcinomas when enhancing the signal with tyramide signal amplification. Neuroendocrine differentiation is thus a common finding in gastric carcinomas when using sensitive methods.

Long-term safety of proton pump inhibitors: risks of gastric neoplasia and infections

After Helicobacter pylori eradication was introduced and largely eliminated the need for maintenance therapy for peptic ulcer disease, gastroesophageal reflux disease (GERD) became the main indication for prolonged gastric acid inhibition. The drug effect on GERD depends on the degree of acid inhibition, thus the efficacious proton pump inhibitors are preferred. The proton pump inhibitors have few immediate side effects, the main concern being the profound hypoacidity and hypergastrinaemia they induce. In short-term, hypergastrinaemia causes rebound hyperacidity, possibly worsening GERD and reducing the efficacy of histamine H2 blockers. In the long-term, hypergastrinaemia causes enterochromaffin-like cell hyperplasia and carcinoids. Since enterochromaffin-like cells may be important in gastric carcinogenesis, iatrogenic hypergastrinaemia may predispose to carcinoma. Gastric hypoacidity also increases gut bacterial infections, and the barrier function of acid against viral and prion infections requires further assessment.

Cytotoxicity of Streptozotocin on Neuroendocrine Cells of the Pancreas and the Gut

Streptozotocin has been used to induce diabetes mellitus in experimental animals and has been thought to have a selective cytotoxic effect on the β-cells in the islets of Langerhans. The aim of the present study was to determine whether streptozotocin has any cytotoxic effect on other neuroendocrine cells of the gastrointestinal tract. Eight female Sprague-Dawley rats received intraperitoneal injections of 100 mg/kg streptozotocin in citric acid buffer; the concentration of streptozotocin was adjusted to 25 mg/ml buffer. Seven rats, serving as controls, received an equivalent volume of the vehicle. The rats were killed after three days and the fundus, antrum, small intestine and pancreas were examined for neuroendocrine cells. Our study confirms that streptozotocin is cytotoxic towards β-cells. In addition, it is cytotoxic towards neuroendocrine cells of the oxyntic mucosa of the stomach. This finding may have clinical significance and suggests that streptozotocin may be used in the treatment of gastric neuroendocrine tumors as well as insulinomas.

Treatment with Proton Pump Inhibitors Induces Tolerance to Histamine-2 Receptor Antagonists in Helicobacter pylori-Negative Patients

BACKGROUND Treatment with H2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) induces hypergastrinemia and causes rebound hypersecretion of gastric acid after treatment, and during treatment with H2RAs tolerance develops. In the present study we investigated whether a treatment period with a PPI induced tolerance to an H2RA. METHODS Thirteen patients with esophagitis were given omeprazole for 90 days. Twenty-four-hour pH monitorings without and with ranitidine were performed before and after treatment with omeprazole. Blood samples and biopsy specimens from the oxyntic mucosa were analyzed for gastrin, histamine, and chromogranin A. RESULTS An increase in mucosal histamine and a reduction in the effect of ranitidine on gastric pH was found 14 days after discontinuing omeprazole compared with before treatment in Helicobacter pylori-negative but not in H. pylori-positive patients. CONCLUSIONS Treatment with omeprazole reduces the effect of ranitidine in H. pylori-negative patients. This is caused by an increase in histamine released by the enterochromaffin-like cell secondarily to hypergastrinemia, corresponding to the tolerance towards H2RAs seen in patients with Zollinger-Ellison syndrome.