Biomedical subjects

R Hopert

Publications and source records attributed to R Hopert.

8 recordsLinked to original sources

PubMed2000

[Helicobacter pylori and coronary heart diseases--hypotheses and facts].

In 1994 Mendall et al. (9) have suggested that there might be a correlation between Helicobacter pylori (HP) infection and coronary heart disease (CHD), mediated by a chronic low-grade acute phase reaction with mildly raised serum or plasma concentrations of C-reactive protein and fibrinogen. According to this hypothesis, a gastric HP colonization might be an additional risk factor for CHD. In the meantime, 35 studies have examined whether HP seropositivity is associated with CHD occurrence. However, in 8 publications only CHD was definitively proven (in CHD+ patients) or excluded (in the corresponding control groups) by coronary artery angiography, and in only 2 of them (1 abstract, 1 full-length publication) a significant association between HP positivity (serologically proven) and CHD was ascertained. Additionally, a metaanalysis of 18 studies including 10,000 patients could not demonstrate any correlations between HP seropositivity and different acute phase proteins (66). Thus, a positive correlation between gastric HP colonization and CHD is far from being proven. Further proposed links between HP infection and CHD such as hyperhomocysteinemia (67) or autoimmune mechanisms (71) due to cross-reacting antibodies to HP HSP60/65 (heat shock protein) with human endothel-derived HSP60/65 need further confirmation.

Acute-Phase Reaction↗

PubMed1990

The effect of an anthraquinone laxative on colonic nerve tissue: a controlled trial in constipated women.

Anthraquinone containing laxatives have been accused to cause degenerative changes in the colonic nerve tissue; prospective studies, however, are not available. This article reports the result of a semiprolective study in 11 matched pairs of chronically constipated women. Each pair consisted of one women having regularly taken an anthraquinone containing laxative for at least one year and a control person without such a medication. Six endoscopic biopsies were taken from the left colon and rectum which were evaluated by electron microscopy and subsequent ultramorphometry for the ratio of damaged to intact neurons, density of neurosecretory vesicles, axonal diameter and number of lysosomes. Medians of the three colonic locations were calculated in each individual and for each variable, and they were compared by non-parametric statistics. Medians of the ratio of damaged to intact neurons in anthraquinone treated women and controls were 0.162 and 0.146 (p = 0.0326, one-tail), medians of the number of type I vesicles were 293 and 348.5 per 100 microns 2 (p = 0.0365, one-tail), respectively. None of the other variables were different between groups. These data do not support the hypothesis that anthraquinone containing laxatives are able to provoke relevant degenerative changes in the colonic nerve tissue since the variables are either similar in both groups or only slight differences could be found which are unlikely to be of pathophysiological relevance.

Adult↗

PubMed1989

[The effect of a calcium carbonate-bismuth subsalicylate combination on intragastric acidity over the course of 24 hours. A randomized study of healthy probands].

Bismuth salts are successfully used for the treatment of campylobacter-pylori-associated gastritis. It cannot be excluded, however, that calcium carbonate, which is present in one of the recommended preparations (calcium carbonate/bismuth subsalicylate, Jatrox), may have an additional therapeutic effect due to an increase of intragastric pH. Therefore, the in-vitro H+ buffering capacity of Jatrox was determined in comparison to other antacids using the pH-stat technique, and its effect on intragastric acidity was tested in 15 healthy volunteers using ambulatory 24-hour pH-metry (combined glass electrode in gastric corpus, solid state memory recorder, sampling rate 30/min). At two study sessions, the volunteers received standardized normal meals (8:00 a.m., 12:00 noon, 6:00 p.m.) and, in randomized order, either Jatrox (three times 2 tablets one hour before meals) or no medication. Under in-vitro conditions, the buffering capacity of Jatrox amounts to 7.82 mmol H+ per tablet (equivalent to 47 mmol H+/24 h at recommended dosage), which is relatively low. Under in-vivo conditions, gastric pH only increases significantly during the first hour after medication. This short-lasting effect, however, has no influence on the 24-hour median pH. It is concluded from these results that the calcium carbonate contained in Jatrox probably does not contribute directly towards its therapeutic effect in promoting the healing of gastritis.

Adult↗

PubMed1989

High amount of dietary carbohydrate does not cause an adaptational increase of stimulated human pancreatic amylase secretion.

In order to investigate whether the human pancreas is capable of adapting to a diet with high-carbohydrate, low-fat, and normal protein content, 10 healthy volunteers were given a defined elemental diet (60% of calories as carbohydrates, 22% as fat, and 18% as protein) for 7 d. For the next 7 d they received an elemental diet with a further increased carbohydrate content (76% of calories) and a decreased fat content (10% of calories). A complete secretin-pancreozymin test was carried out at the end of the first wk and at d 14. The results show that an increase in dietary carbohydrate does not provoke an adaptational response of stimulated secretion rates of amylase, trypsin, and chymotrypsin in humans, as expected from animal experiments.

Acclimatization↗

PubMed1989

Recommendations for long-term oesophageal pH monitoring.

Ambulatory 24-h pH monitoring in the distal oesophagus represents a widely accepted tool in the diagnosis of gastro-oesophageal reflux disease. When this method was first established, most attention was drawn to the definition of normal oesophageal pH values; various studies correlated morphological findings in the distal oesophagus with the extent of gastro-oesophageal reflux. We have compared different reflux-related variables under different measuring conditions; reflux time (percentage of time with pH below 4) was found to be much more reliable than variables derived from the recognition of single reflux episodes. The special advantage of long-term ambulatory pH monitoring is, however, in our opinion, its capacity for identifying gastro-oesophageal reflux as the primary cause of chest pain in those patients whose oesophagus has an endoscopically normal appearance. For this purpose, it is vital that the recording system be equipped with a reliable event marker; the oesophageal origin is confirmed by detection of a high coincidence between pain attacks and reflux episodes. The evaluation software for ambulatory pH monitoring must therefore allow for diagrammatic display of a complete 24-h recording where the onset of pain attacks is visible within the pH curve.

Chest Pain↗

PubMed1989

Basic principles of pH registration.

Normally, pH-sensitive electrodes are used for measuring the acidity of an aqueous solution. A second electrode is required as reference and can be integrated in the pH-sensitive electrode (combined electrode); separate reference electrodes must be used, however, when combined ones are not available. Types of electrodes are: glass, antimony, ISFET and polymeric membranes; only glass and antimony electrodes are commercially available. Different factors determine the accuracy of a pH measurement, the most important being: (1) electrical and mechanical properties of the electrodes; (2) ionic strength, temperature and background activity of the test solution; and (3) electrical properties of the pH amplifier and display. The highest accuracy of about 0.1 pH units can be obtained with the glass electrode; the error of measuring systems equipped with antimony electrodes does not normally exceed 0.5 pH units. It is important to define the required accuracy prior to measurement. If, for example, long-term oesophageal pH monitoring is performed in newborns or infants, the best compliance is achieved with the relatively small and flexible antimony electrode. If, on the other hand, the effect of an allegedly weak drug on gastric acidity is to be tested in a volunteer study, only glass electrodes will be appropriate.

Antimony↗

PubMed1982

Three-dimensional structure and cell kinetics at different sites of rat intestinal remnants during the early adaptive response to resection.

In this study the early phase of the morphological adaptation of rat ileum after a proximal resection of 60% has been studied using microdissection and cell labelling techniques. Resected rats and sham-operated controls were killed 2, 4, 6, 10 and 12 days after surgery. Intraperitoneal injections of 3H-thymidine were carried out 24 or 12 h prior to sacrifice. In the latter groups mitotic arrest was achieved by vincristine. A stereo-microscope was used to measure and calculate the following parameters: intestinal diameter; villus: height, width, breadth at base and apex, surface, enterocytes per 100 micrometers length, cell pool, number of villi and absorptive surface per mm2 serosal area; crypt: length, enteroblasts per 100 micrometers length and per column, cell columns and mitoses per crypt, cell pool, crypts, and mitoses per unit serosal area; cell kinetics: migration rate, villus transit time. To test the influence of treatments, postoperative time course and the location of the intestinal segment and their possible interactions, factorial analyses of variance were carried out on the parameters investigated. The main findings, demonstrated for the first time, were: 1. An increase in the villus surface which was achieved by proportional enlargement of villus geometry; 2. This increase in the villus surface led to an enlarged absorptive surface per unit serosal area; 3. A reduction of villus transit time of the individual enterocyte; 4. A most pronounced magnitude of adaptative response in the proximal remnants which was gradually diminished in aboral direction, and 5. A sequential course of adaptative response of the various crypt parameters investigated.

Animals↗

PubMedDate not supplied

Reduction of 24-hour gastric acidity by different dietary regimens: a randomized controlled study in healthy volunteers.

Evidence from animal experiments suggests that intraduodenal infusion of nutrients leads to an inhibition of gastric acid secretion via an enterogastric feedback mechanism. Detailed data are lacking, however, on the difference in circadian gastric acidity between gastric and intraduodenal alimentation in man. We conducted a randomized study in 10 healthy volunteers (5 men, 5 women, age 22-30 yr). From 8:00 am of the first study day until 4:00 pm of the next day, either a standardized normal meal or a liquid polymer diet (Fresubin) was given orally at 8:00 am, noon, and 6:00 pm. In a third experiment, a liquid hydrolysed diet (Survimed OPD) was continuously applied to the duodenum using a portable pump. Daily caloric intake and main nutrient components were comparable in all three diets. From 2:00 pm of the first day until 4:00 pm of the next day, an intragastric pH-metry was performed with a combined glass pH-electrode in the gastric corpus. Median pH-values from predefined time periods (whole day, prandial, interdigestive, nocturnal) were compared between the three groups. The orally applied liquid polymer diet led to a significantly stronger increase in 24-hr and prandial gastric pH than the normal diet. Twenty-four-hr, interdigestive, and nocturnal pH-median values were significantly higher during continuous intraduodenal application of the liquid hydrolysed diet than during the normal diet.

Adult↗