Search PubMed⌕ Search

Biomedical subjects

H Petersen

Publications and source records attributed to H Petersen.

At least 19 recordsLinked to original sources
PubMed1992

[Clinical assessment of acute ankle injuries in relation to the need of radiography].

The object of the present investigation was to attempt to assess the value of some selected individual aspect of the clinical examination of patients with acute ankle injuries with tenderness, swelling or haematoma in the neighbourhood of the lateral malleolus. An attempt was made to investigate whether it was possible to differentiate the group of patients in whom radiographic examination of the ankle was necessary and whether this could be done with sufficient certainty on the basis of the clinical parameters examined. The results are presented in the form of calculation of the diagnostic frequencies. Absence of tenderness over the posterolateral edge of the lateral malleolus was found to be the clinical finding which could be employed to exclude fracture with greatest certainty, as the true negative diagnostic frequency was found to be 97.33 (90.70-99.68). This certainty is of the same magnitude as the certainty of previously selected criteria but the examination appears to be simpler and more objective.

Acute Disease↗
PubMed1992

Can NSAIDs cause acute biliary pain with cholestasis?

Two patients had many acute episodes of biliary pain with elevated liver function tests 12-48 h after the last ingestion of nonsteroidal anti-inflammatory drugs (NSAIDs) (including paracetamol) alone or in combination with codeine. One had known intolerance to NSAIDs, but paracetamol had not been previously incriminated in the pathogenesis of the attacks. In this patient the combined use of paracetamol and codeine probably also increased the severity of the episodes. We conclude that in some patients in whom endoscopic cholangiography is normal, biliary pain and abnormal liver function tests could be the result of NSAIDs. A thorough drug history is required in such cases.

Acetaminophen↗
PubMed1992

Cimetidine on-demand in dyspepsia. Experience with randomized controlled single-subject trials.

Double-blind randomized controlled trials in single subjects (N of 1 RCTs) have demonstrated a beneficial symptomatic effect of cimetidine in reflux- or ulcer-like non-ulcer dyspepsia (NUD). However, spontaneous fluctuations in symptoms reduce the validity of such trials when performed as continuous trials with fixed dosages. This study was carried out to identify individual responders to cimetidine in NUD, peptic ulcer disease, and oesophagitis and to confirm the beneficial average effect of cimetidine in these clinical entities. We evaluated N of 1 multi-crossover trial designs, which compare the effects of single doses of cimetidine and placebo taken on-demand for symptomatic relief. Each trial consisted of six cimetidine (400 mg or 800 mg) and six placebo tablets randomized in successive pairs. The symptomatic effect of each tablet was measured 1/2-6 h after the intake. Outcomes were assessed by individual p values and confidence intervals. A minimal clinically important difference was defined, to assess the clinical significance as demonstrated by the confidence intervals. Thirteen of 25 patients (52%) with reflux- and ulcer-like NUD obtained individual p values below 0.20. Similarly, 7 of 9 patients (78%) with oesophagitis and 6 of 12 patients (50%) with peptic ulcer obtained such p values. On the basis of the 80% confidence intervals the corresponding numbers of subjects with clinically significant effect were six (NUD), three, and three. The combined data showed a significantly better effect of cimetidine than of placebo (p less than 0.0001) in each of the three diagnostic groups studied. Cimetidine taken on-demand may have a rapid symptom-relieving effect in dyspepsia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Differential protective effects of O-phenanthroline and catalase on H2O2-induced DNA damage and inhibition of protein synthesis in endothelial cells.

The respective roles of H2O2 and .OH radicals was assessed from the protective effects of catalase and the iron chelator o-phenanthroline on 1) the inhibition of protein synthesis, and 2) DNA damage and the related events (activation of the DNA repairing enzyme poly(ADP)ribose polymerase with the associated depletion of NAD and ATP stores) in cultured endothelial cells exposed to the enzyme reaction hypoxanthine-xanthine oxidase (HX-XO) or pure H2O2. Catalase added in the extracellular phase completely prevented all of these oxidant-induced changes. O-phenanthroline afforded a complete protective effect against DNA strand breakage and the associated activation of the enzyme poly(ADP)ribose polymerase. By contrast, iron chelation was only partially effective in maintaining the cellular NAD and ATP contents, as well as the protein synthetic activity. In addition, the ATP depletion following oxidant injury was much more profound than NAD depletion. These results indicate that: 1) .OH radical was most likely the ultimate O2 species responsible for DNA damage and activation of poly(ADP)ribose polymerase; 2) both H2O2 and .OH radicals were involved in the other cytotoxic effects (inhibition of protein synthesis and reduction of NAD and ATP stores); and 3) NAD and ATP depletion did not result solely from activation of poly(ADP)ribose polymerase, but other mechanisms are likely to be involved. These observations are also compatible with the existence of a compartmentalized intracellular iron pool.

Adenosine Triphosphate↗
PubMed1991

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.

Adult↗
PubMed1991

The symptomatic effect of 1-day treatment periods with cimetidine in dyspepsia. Combined results from randomized, controlled, single-subject trials.

Before endoscopy a double-blind, randomized, controlled, single-subject trial comparing the symptomatic effect of 1-day treatment periods with cimetidine and placebo was conducted in patients with dyspepsia. Results from 339 patients were analysed. The trial lasted 12 days and consisted of 6 treatment days with 400 mg cimetidine three times daily and 6 days with placebo three times daily. The order of the treatments was randomized within six pairs, and a randomization test based on daily measures of global symptoms provided individual p values. Aggregation of the measures from all subjects showed that cimetidine alleviated the symptoms significantly better than placebo in peptic ulcer disease (PUD) (p less than 0.0001), oesophagitis (p less than 0.001), and non-ulcer dyspepsia (NUD) (p less than 0.0001). Twenty-seven per cent of the patients with PUD, 26% of those with oesophagitis, and 12% of the patients with NUD obtained individual p values of less than 0.10 and were defined as responders. The best predictors of the response to cimetidine in NUD were age above 40 years, heartburn or acid regurgitations being the worst symptom, and night pains relieved by food, milk, or antacids. In conclusion, the applied single-subject trial confirmed the overall symptomatic effect of cimetidine in dyspepsia and identified individual responders among patients with NUD with a clinically reasonable profile. The low proportion of responders among patients with PUD or oesophagitis suggests that the model has a low sensitivity for identification of individual responders and that the single-subject trial design in dyspepsia needs further refinement.

Adult↗
PubMed1991

Effect of the histamine-1 antagonist astemizole alone or with omeprazole on rat gastric mucosa.

The stimulation of acid secretion by gastrin may in the rat be explained solely by gastrin-induced histamine release. This study was done to examine whether histamine could mediate the general trophic effect of gastrin on the oxyntic mucosa, by using a long-acting selective histamine-1 antagonist (astemizole) alone or with omeprazole-induced hypergastrinaemia for 90 days in female Sprague-Dawley rats. At day 90, isolated vascularly perfused rat stomachs were prepared to study maximal gastrin- and histamine-stimulated acid and pepsinogen outputs and maximal gastrin-stimulated histamine release. Oxyntic mucosa morphometry, mucosal histamine and pepsinogen contents, and plasma gastrin and histamine levels were also determined. For the first time, omeprazole has been found to inhibit gastric emptying and to increase plasma histamine. As compared with controls, astemizole alone did not influence plasma gastrin, increased plasma histamine in only some rats, and gave a slight increase in all other variables. Together with omeprazole, it further increased variables already stimulated by omeprazole. Thus, mucosal thickness, histamine concentration, and chief-cell density in oxyntic mucosa were significantly higher in astemizole/omeprazole-treated rats than in omeprazole-treated rats. Gastrin-stimulated histamine release was increased in both astemizole- and omeprazole-treated rats. For all rats plasma histamine was significantly correlated with plasma gastrin and with numerical fundic argyrophil cell density. In conclusion, the present study confirms the trophic effect of gastrin and shows a slight trophic effect of astemizole on the oxyntic mucosa. It also shows that plasma histamine may reflect the argyrophil cell density in the oxyntic mucosa and that omeprazole inhibits gastric emptying.

Animals↗
PubMed1991

Histamine and the stomach: introduction.

The physiologic role of histamine in the stomach has for many years been a subject of controversy. The introduction of histamine-2-receptor antagonists and, later, of proton pump inhibitors has not only stimulated the interest in the topic but has also made it relevant for the clinician. The main and still unsettled issue is the interrelationship between histamine and gastrin on the parietal cell.

Gastric Acid↗
PubMed1991

Trophic effect of histamine on the stomach.

On the basis of clinical observations and experimental animal studies it has been established that gastrin has a trophic effect on the oxyntic mucosa. On the other hand, histamine, being at least as efficient as gastrin as an acid secretagogue, has experimentally been reported not to have such trophic effect. However, during the last few years both endogenously and exogenously induced hypergastremia have been shown to have a specific trophic effect on the enterochromaffin-like (ECL) cell and a less pronounced and later detectable general trophic effect on the oxyntic mucosa. Moreover, in the rat (the species in which most of the trophic studies have been done) the acid-stimulatory effect of gastrin may be solely explained by stimulation of histamine release from ECL cells. Therefore, it seemed natural to evaluate whether the general trophic effect of gastrin could also be caused by histamine or another substance released from the ECL cells. In this review we challenge the concept that maximal pentagastrin-stimulated acid secretion only reflects the parietal cell mass, since the acid-stimulatory effect of gastrin is mediated by histamine release. Therefore, maximal pentagastrin-stimulated acid secretion reflects both the ECL cell mass and the parietal cell mass. With regard to the possible trophic effect of histamine, we show that the doses previously used have been inadequate. Furthermore, histamine has been reported to have a trophic effect on the parietal cell in the dog; some patients with hyperhistaminemia have an increased maximal histamine-stimulated acid secretion, suggesting an increase in the parietal cell mass; and there is parietal cell hyperplasia in the oxyntic mucosa surrounding the histamine-producing carcinoids in mastomys.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The controlled single subject trial.

Randomized controlled trials in single subjects ('N of 1 RCT') are double-blind, multi crossover trials in which the effects of two or more treatments are compared within one individual. The aim is to provide a controlled assessment of the efficacy of a new drug in a specific patient. Suitable diseases for single subject trials are particularly those which significantly impair the quality of life and in which there are uncertain treatment effects. Appropriate drugs should have a prompt action, a minimum of carry-over effect, and no side-effects. The trial design is determined by the length, number, and order of successive treatment periods, the outcome measures, and the statistical requirements. Each of these elements may be altered and tailored to the clinical entity and drug(s) applied, thus, providing a large potential for design options.

Double-Blind Method↗
PubMed1991

Combined single subject trials.

Randomized controlled single subject trials are designed as multiple crossovers between the treatments to be compared. Results from such independent trials may be combined and integrated for the purpose of extending the conclusions beyond the single subject. Unlike the conventional crossover group trial, the primary goal of the combined single subject study is not to demonstrate an overall clinical benefit of a drug, but to indicate the features typical for drug responders. The external validity of combined single subject trials depends on the same prerequisites as are employed in group trials: strict entry criteria, uniform treatment procedures, consensus targets for outcome measures, and acceptable statistical tests. In clinical research the main role of combined single subject trials should be to elucidate new insight and generate hypotheses that could optimize the design of subsequent group trials.

Data Interpretation, Statistical↗
PubMed1990

Statistical aspects of controlled single subject trials.

Randomized controlled trials in groups and single subjects differ in several statistical aspects. In group trials the experimental unit is a randomly selected subject from a predefined population and this subject is randomly assigned to a treatment. Outcome is confined to average effects which can be generalized to the specific population, but which do not necessarily apply to individual persons. In single subject trials the experimental unit is a treatment period and each treatment period is randomly allocated in a multiple cross-over sequence of periods. The single subject is only representative of itself, but similar responses in corresponding single subject trials may justify careful extrapolation of the results. Single subject trials have a high risk of Type II errors. However, the randomization procedure chosen and the type of statistical test applied may enhance the statistical power of such trials. Internal validity depends on modeling the trial design to the clinical features, drug properties and statistical requirements, while reliability is determined by the reproducibility of the trial response.

Humans↗
PubMed1990

Dependence of antigen expression on functional state of beta-cells.

Antigen expression corresponding to anti-islet cell surface monoclonal antibodies IC2 and A2B5 was studied. IC2 is a rat-rat hybridoma autoantibody produced from the BB rat; among islet cells, IC2 is beta-cell specific. A2B5 is an anti-ganglioside antibody described as labeling beta-cells. Islets of Langerhans from Lewis rats were isolated and cultured for 18 h in RPMI-1640 with five different glucose concentrations (2.2, 3.3, 5.5, 11.1, and 18.3 mM). In some experiments, islets were precultured for 2 or 3 days. After isolation of islet cells and antibody labeling, the percent of IC2+ beta-cells in the different groups increased from 33.3, 34.5, 40.9, and 57.2 to 58.6% (P less than 10(-6). For A2B5, the percent of labeled islet cells increased from 37.4, 41.8, 46.7, and 53.8 to 56.2% (P less than 10(-4). Thus, increasing glucose concentration leading to higher beta-cell activity implies an increase in antigen expression. Neither A2B5 nor IC2 reacts with insulin, as shown by absorption experiments and immune electron microscopy of binding sites. Electron microscopy of IC2-gold-labeled islet cells substantiated the beta-cell specificity of IC2. In conclusion, expression of the corresponding antigens to IC2 and A2B5 depends on the functional state of the beta-cells; because this has been shown to be an important factor in the development of insulin-dependent diabetes, our findings may be of potential pathogenetic interest.

Animals↗
PubMed1990

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.

Adult↗