Search PubMed⌕ Search

Biomedical subjects

C Ohmann

Publications and source records attributed to C Ohmann.

At least 127 records · Page 7Linked to original sources
PubMed1985

[Symptomless and complicated peptic ulcer as an extreme clinical form of ulcer disease: consequences for choice between conservative and surgical therapy].

Asymptomatic recurrent ulcers following drugs and surgical therapy are true failures of treatment (Visick IV). Several types of bias at present do not allow any conclusion whether medical treatment and maintenance increase the rate of ulcer complications. The mechanisms of action for medical treatment with cimetidine and operative treatment with SPV are similar, but not identical. Bad compliance and incomplete vagotomies mainly account for success of mutual exchange between the two types of therapy. Using a decision tree with mortality as outcome recommendations are developed for a step-wise therapeutic concept in peptic ulcer patients.

Cimetidine↗
PubMed1985

Sample taking problems in measuring actual histamine levels of human gastroduodenal mucosa: specific and general relevance in clinical trials on peptic ulcer pathogenesis and selective proximal vagotomy.

Changes in histamine storage in the oxyntic mucosa of duodenal ulcer patients and their reversal by vagotomy and the histamine H2-antagonist cimetidine supported the hypothesis that histamine could be a causal factor in peptic ulcer pathogenesis. The specificity of these findings was impaired by problems in biopsy taking, however, and in the preparative steps before measuring the actual histamine contents in all parts of the gastric mucosa and in the duodenum. A prospective trial was carried out in 190 patients to identify these sources of bias and to overcome them by appropriate study designs. Usually a direct correlation was found between weight of biopsy and mucosal histamine content. This problem was solved by selecting a biopsy forceps producing smaller variations in sample size, by limiting the time of cold ischaemia to four to five minutes only and by taking three biopsy specimens for each single histamine value. The actual histamine content of mucosal biopsies remained constant for about four to five minutes only. The 'disappearance' rate was faster in control subjects than in duodenal ulcer patients. Hence by variation of the cold ischaemia time any artefacts of differences between mucosal histamine levels in controls and duodenal ulcer patients could be produced. Using the optimised sample taking procedure mucosal histamine contents of several gastric regions and the duodenal bulb were measured in 24 patients with duodenal ulcer, after selective proximal vagotomy without drainage and in control subjects without any stomach disease (randomised controlled trial). The histamine content was lower in all parts of the upper gastrointestinal tract in duodenal ulcer patients than in controls and was raised again in all regions after selective proximal vagotomy. As the most likely hypothesis it is suggested that vagal reflexes with afferent fibres coming from the oxyntic mucosa stimulate histamine release in duodenal ulcer patients by efferent peptidergic neurones to all parts of the stomach and the duodenum where the ulcer lesion is situated.

Adult↗
PubMed1984

[Acute coronary insufficiency during induction of anesthesia following anthracycline chemotherapy].

Cytostatic treatment with anthracyclines lines can lead to acute or chronic myocardial insufficiency. A cumulative dose of less than 500 mg/m2 body surface area can in general be regarded as safe. A case of acute cardio-circulatory insufficiency during induction of anesthesia is described, in which the total cumulative dose did not exceed 250 mg/m2 body surface area. The pathophysiological mechanisms occurring and the diagnostic and therapeutic measures necessary are discussed.

Anesthesia↗
PubMed1982

Assay and identification of histamine in human gastric aspirate by a fluorometric--fluoroenzymatic technique. Its application in patients with chronic duodenal ulcer.

Histamine assays can be unreliable in individual subjects or samples even though the particular method is in general working very well. Therefore the specificity and accuracy of histamine determination in the gastric aspirate of individual duodenal ulcer patients was thoroughly examined and shown to be satisfactory. Pitfalls of the fluorometric assay were investigated. A native (non-histamine) fluorescence in gastric aspirate which occurs before the addition of OPT was not removed by the original Shore procedure. In the combined assay (Dowex 50 + butanol extraction) this fluorescence no longer interferes with the assay. For the identification of histamine in a single gastric aspirate of an individual duodenal ulcer patient, the reversed blank (3 M HCl added to the reaction mixture before OPT instead after OPT), excitation and fluorescence spectra, the heating test with spectra recorded and the HMT test were found to be reliable. The formaldehyde test and the heating test without recording the spectra were useless since they gave false negative results. Since the HMT test was regarded as a reference method it was thoroughly investigated both by theoretical considerations (enzyme kinetics) and by a series of measurements in a single patient as well as in a group of nine subjects. Samples from the period of peak acid output in response to pentagastrin showed an average histamine concentration of about 8 ng/ml and a histamine output of 1.5 microgram/30 min.

Adult↗
PubMed1982

Histamine release and hypotensive reactions in dogs by solubilizing agents and fatty acids: analysis of various components in cremophor El and development of a compound with reduced toxicity.

Anaphylactoid reactions in man following administration of drugs solubilized with cremophor El (polyethylenglycolglycerol riconoleate) are a considerable clinical problem. Since these reactions occur in dogs on first exposure and in pigs on second exposure, the 'dog model' was used in this communication to analyse components and chemical modifications of cremophor El and its components for their clinical effects, their hypotensive actions and their histamine-releasing capacity. Two series of experiments in 1978 and 1980 were performed in 144 adult mongrel dogs of both sexes. In these studies histamine release was not related to the effect of the solubilizing agents as tensides and was elicited by rather low doses (about 10--100 mg/kg i.v.). The effect of these substances on blood pressure and on blood histamine levels was connected with distinct chemical features: the most potent compounds were oxethylated and additionally esterified unsaturated or hydroxylated fatty acids. Several phases in hypotensive reactions were observed, including an immediate response, a delayed blood pressure response and a late response about 15--20 min after injection. Only the delayed response was associated with histamine release. The combination of cardiovascular effects and histamine release was fatal on some occasions indicating that histamine release can be dangerous. Compared to cremophor El, the tenside effect was equal, but the toxicity was reduced in oxethylated 12-hydroxystearic acid. It is recommended that this solubilizer should be used in further extended studies in animals and - if these are successful - in clinical trials.

Animals↗
PubMed1981

Intestinal diamine oxidase and histamine release in rabbit mesenteric ischemia.

It has been suggested that histamine contributes to lethal circulatory collapse after acute superior mesenteric artery occlusion. The activity of the histamine inactivating enzyme diamine oxidase, the release of the amine, and the effect of histamine receptor antagonists was therefore studied in rabbits. The main results were: (a) Diamine oxidase activity decreased by 60% after intestinal ischemia and reperfusion. A monoexponential dose-response relationship was found between the specific diamine oxidase inhibitor aminoguanidine and reduced survival time. (b) Plasma histamine levels in the right atrium rose only slightly after ischemia, but considerably during reperfusion of the gut, and remained high for at least 20 min. In sham-operated animals the plasma histamine concentration was unchanged throughout the experiment. The histamine content in the intestinal wall did not fall significantly at any time after mesenteric artery occlusion and reperfusion. (c) The aminoguanidine-induced reduction in survival time was completely reversed by pre-treatment of the animals with the H1-receptor antagonist dimethylpyridine and the H2-receptor antagonist cimetidine. This study provides strong evidence for the protective role of intestinal diamine oxidase in intestinal ischemia.

Amine Oxidase (Copper-Containing)↗
PubMed1981

[A clinical study of co2-elimination using a modified bain-system (author's transl)].

Of three groups of anaesthetized and intubated patients (n = 7) under controlled ventilation two received fresh gas flows of 70 ml/kg . min, 100 ml/kg . min and 130 ml/kg . min either in increasing or in decreasing amounts via a Bain circuit, while the third group was ventilated via a conventional semi-closed anaesthesia circuit. Blood gas analyses and cardiovascular parameters were recorded. In one patient temperatures and relative humidities of in- and expired gases were obtained by psychrometry. A modification of the Bain system afforded control of respiratory minute volumes and airway pressures. CO2-elimination proved to be adequate at a fresh gas flow of 130 ml/kg. min. At 100 ml/kg. min it was acceptable still, however pH values were outside normal range. With 70 ml/kg . min mean capillary pCO2 values (42.6 mmHg and 43.2 mmHg) and mean pH values (7.32 and 7.33) in the two respective groups proved a respiratory acidosis. Capillary pO2 was above 100 mmHg in all groups. Temperature and relative humidity of inspired gases were 24 degrees C and 40 per cent, 23 degrees C and 25 per cent, 22 degrees C and 3 per cent at fresh gas flows of 70, 100 and 130 ml/kg . min respectively.

Adult↗
PubMed1980

[Effect of planned treatment policy in patients with upper gastrointestinal bleeding using endoscopic neodymium-YAG laser therapy (author's transl)].

In a prospective trial with and without laser therapy the outcome on 105 patients was evaluated according to a defined protocol and terminology. Only patients with actively bleeding lesions during early endoscopy had laser therapy. Patients showing evidence of recent bleeding or no bleeding had none. Defects of the laser equipment or impossibility of reaching a bleeding lesion prevented its use in some patients (control group). There was no difference concerning rate of recurrent bleeding or mortality. Controlled trials with defined groups of patients are urgently needed.

Adolescent↗
PubMedDate not supplied

Selection of variables using 'independence Bayes' in computer-aided diagnosis of upper gastrointestinal bleeding.

In this paper two problems of computer-aided diagnosis with 'independence Bayes' were investigated: selection of variables and monotonicity in performance as the number of measurements is increased. Using prospective data from patients with upper gastrointestinal bleeding, the stepwise forward selection approach maximizing the apparent diagnostic accuracy was analysed with respect to different kinds of bias in estimation of the true diagnostic accuracy and to the stability of the number and type of variables selected. The results of this study suggest first that the selection of variables should be evaluated against the estimated true diagnostic accuracy obtained using all variables, and secondly that the results of a single selected sequence may be severely biased.

Bayes Theorem↗
PubMedDate not supplied

Proposed definitions for diagnosis, severity scoring, stratification, and outcome for trials on intraabdominal infection. Joint Working Party of SIS North America and Europe.

Analysis of the experience with scientific studies on patients with secondary intraabdominal infection has revealed that problems of interpretation and comparability between studies exist as they relate to variable diagnostic criteria, unmeasured severity of disease, and unclear outcome measures. A consistent system of definitions has been developed to address these deficiencies. Intraabdominal infection is defined as clinical peritonitis requiring both operative and microbiological confirmation for proof of infection. The APACHE II system is proposed for grading the severity of the infection and for stratification of patient risk of mortality. Mortality and time until death, on one hand, and recovery and time until recovery, on the other, are proposed as the main outcome measures, both being independently and positively defined. It is anticipated that this system of minimum rules will produce studies that can be compared, hence, accelerating knowledge and understanding about intraabdominal infection and its best treatment.

Abscess↗
PubMedDate not supplied

Acute acalculous cholecystitis complicating trauma: a prospective sonographic study.

Acute acalculous cholecystitis (AAC) is a well known complication in severely traumatized patients. Existing data of AAC originate from retrospective analyses and episodic case reports. In a prospective study 45 polytraumatized patients admitted to our intensive care unit from January 1989 to June 1990 were clinically and sonographically screened for this condition at defined time intervals. Trauma scoring was performed according to the injury severity score and polytrauma score. AAC was defined as a combination of hydrops of the gallbladder, an increased wall thickness (> 3.5 mm), and the demonstration of sludge. We were able to document this diagnostic triad in 8 (18%) of 45 patients. As a consequence early elective cholecystectomy was performed in 1 of the 8 patients. The remaining patients were treated conservatively. The incidence of AAC in severely traumatized patients is higher than figures so far published suggest. Ultrasound is a reliable method of early detection and follow-up of this complication.

Acute Disease↗
PubMedDate not supplied

Acute acalculous cholecystitis in severely traumatized patients: a prospective sonographic study.

Acute acalculous cholecystitis is a well known complication in severely traumatized patients. Existing data originate from retrospective analyses and episodic case reports. In a prospective ultrasonographic study 25 polytraumatized patients admitted to our intensive care unit between January 1, 1989, and December 31, 1989, were examined in daily intervals for this condition. Trauma scoring was performed according to the injury severity score (ISS) and polytrauma score (PTS). "Stress cholecystitis" was defined as a combination of hydrops of the gallbladder, an increased mural thickness (> 3.5 mm), and the demonstration of "sludge." We were able to demonstrate this diagnostic triad in four out of 25 patients (= 16%). As a consequence early elective cholecystectomy was done in one patient. The remaining patients were treated conservatively. The incidence of stress cholecystitis in severely traumatized patients is probably higher than figures so far published suggest. Ultrasonography is a reliable method of early detection and follow-up for this complication.

Acute Disease↗
PubMedDate not supplied

Prognostic scores and design of clinical studies.

Randomized controlled clinical trials are the preferred scientific method and remain the vital bridge between basic science and improvements in health care according to general agreement. However, discussion has revealed various critical issues in the field of intraabdominal infection. Many of these critical points can be dealt with by prognostic scoring systems. In this paper the application areas for scores in clinical trials on intraabdominal infections are presented. These areas cover: assessment of severity of disease, definition of inclusion/exclusion criteria, analysis of comparability, adjustment for noncomparability, definition of end points and comparison of observed versus predicted outcome. The use of scoring systems in defining treatment policies is still experimental.

APACHE↗