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Biomedical subjects

R Eberhardt

Publications and source records attributed to R Eberhardt.

At least 37 records · Page 2Linked to original sources
PubMed1996

Improved traceability of pH measurements.

Traceability is a prerequisite for the comparability and uniformity of measurements. Although pH-measurements are carried out on a large scale in laboratory and industry, the problems involved in the traceability of pH values have not adequately been solved in the past. The comparability of pH measurements is limited, among other parameters, by the accuracy of the pH values of the standard buffer solutions used to calibrate the pH meter-electrode assemblies. The measured pH(X) value must be traceable to primary standard pH(PS) values through an unbroken chain of comparisons, all values having stated uncertainties. A new primary standard measurement device for pH is used to certify primary pH reference materials from which these secondary reference materials can be derived.

Journal Article↗
PubMed1995

[DMSO in patients with active gonarthrosis. A double-blind placebo controlled phase III study].

BACKGROUND: For the patient, the most important aspect of gonarthrosis is pain and the associated impairment of movement.-- METHOD: In a randomized, placebo-controlled, double-blind study involving 112 patients (56 in each of the two groups test substance and placebo) the efficacy and tolerability of DMSO gel 25% applied over a period of three weeks were investigated in comparison with placebo. In addition to an assessment by the doctor of pain under loading while going about daily activities, rest pain, pain on palpation and of loss of mobility, the patient also kept a pain diary.-- RESULTS: In comparison with the gel base used as placebo, percutaneous treatment with DMSO proved to have a clinically relevant analgesic effect on the intensity of loading pain during everyday activities (p = 0.019). A positive effect of DMSO was also seen for pain intensity at rest (p = 0.015) and pressure pain (p = 0.029). The pain diary also reflected these observations. No serious adverse events or changes in laboratory values were observed.

Administration, Topical↗
PubMed1994

On-line monitoring of an animal cell culture with multi-channel flow injection analysis.

A multi-channel flow injection analysis system was used for on-line monitoring of a continuous animal cell culture with high cell density. With this system, the glucose, lactate and glutamine concentration were determined using immobilized dehydrogenases, ammonium using an aqueous o-phthaldialdehyde solution. Glutamine concentration was determined on the basis of the difference between a glutamine and a glutamate measurement. To prevent disturbance of the measurement and pollution of the system, the analytes in the sample were separated from high molecular compounds by on-line dialysis. On-line gas dialysis was used to avoid interference of other amino groups with the ammonium determination. In addition, dialysis was used as a dilution step. The measurement time for all four components was 42 min. This time included a final washing period after the analysis cycle. The system was calibrated once a day. Two continuous cultivations of a hybridoma cell line immobilized in open-porous glass carriers were monitored, using a fluidized bed reactor as cultivation system. The concentration of glutamine, glucose and ammonium determined with the on-line FIA system were in good agreement with the off-line data determined once a day. Only the lactate data showed some deviation. The immobilized enzyme reactors could be used for up to 3000-5000 injections. During the first cultivation, lasting 200 h, the start up period of the reactor was monitored. The on-line measurements described much better the time-course of the concentrations than the off-line data. It was possible to estimate the growth rate of the cells in the micro-carriers by the on-line data. In the course of the second cultivation, which lasted almost 1000 h, the influence of the dissolved oxygen concentration on the cell metabolism was monitored. It was noted that a sudden change of the glutamine concentration in the feed caused a fast change of the consumption and production rate of the measured metabolites.

Animals↗
PubMed1994

Long-term therapy with the new glucocorticosteroid deflazacort in rheumatoid arthritis. Double-blind controlled randomized 12-months study against prednisone.

The long-term anti-inflammatory and immunosuppressive properties and the safety of deflazacort (Calcort, CAS 14484-47-0) were assessed investigating the effect on clinical symptoms and safety parameters in patients with rheumatoid arthritis compared to prednisone as standard therapy in a randomized double-blind controlled clinical trial. Monitoring was performed according to GCP-guidelines closely in order to have a maximum of the patients entered completed at the end of the 12-month therapy with high data quality. 76 patients, meeting the criteria for classical or definite rheumatoid arthritis and requiring corticosteroid therapy, were randomly allocated to a 12-months treatment with either deflazacort (6 mg/tablet) or the corticoid standard prednisone (5 mg/tablet). Steady state dosage between 1/2 and 3 tablets per day was individually adjusted according to the severity of the clinical symptoms. Due to the close monitoring of the trial in the 6 study centres, 25 patients completed 12 months of deflazacort and 28 patients 12 months of prednisone treatment, being controlled 7 times during the trial. Five efficacy parameters were assessed at each visit: Ritchie Index, duration of morning stiffness, grip strength, effective dosage of study medication and global assessment of disease status. Following safety and tolerance parameters were controlled during the trial: vital signs, weight, Cushing's symptoms and adverse events at each visit; 32 laboratory parameters at 6 visits; ECG at 3 visits; and the global tolerance was assessed at the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Hydrolysis of short acyl chain inositol lipids by phospholipase C-delta 1.

We investigated the relationship between substrate aggregation and activation of phosphoinositide-specific phospholipase C-delta 1 (PLC-delta 1), isolated from bovine brain cytosol. The inositol lipids 1,2-dibutyryl-sn-glycero-3-phosphoinositol (di-C4-PI), 1,2-dihexanoyl-sn-glycero-3-phosphoinositol (di-C6-PI), and 1,2-dioctanoyl-sn-glycero-3-phosphoinositol (di-C8-PI) were prepared from synthetic cytidine diphosphate diglyceride analogs in a reaction with myo-inositol catalyzed by yeast phosphatidylinositol synthase. All three lipids served as substrates for PLC-delta 1 at concentrations significantly below their critical micelle concentration (cmc). Under these conditions, steps that might limit the reaction rate, such as membrane adsorption or penetration into the phospholipid surface, were eliminated. Below the cmc, the concentration of lipid substrate required to produce hydrolysis followed the order: di-C8-PI < di-C6-PI << di-C4-PI. Calcium was essential for hydrolysis of the short chain substrates at all lipid concentrations tested. The dependence of the reaction on calcium suggests that this ion activates PLC-delta 1 at a step other than adsorption to or penetration of the membrane surface. As the concentration of di-C8-PI was raised above the cmc, the reaction velocity increased 2-3-fold. These results are consistent with the idea that micellar or bilayer aggregates of phosphoinositol are not required for PLC-catalyzed hydrolysis, although the reaction rate is enhanced by micelle formation.

Animals↗
PubMed1992

Risk characterization and the extended spaceflight environment.

Recent trends toward prolonged space flights have highlighted concern over potential health hazards for crews occupying a confined habitat for an extended duration mission. Previous spaceflight and remote habitat experiences have identified a large number of compounds that pose potential hazards as space habitat contaminants. A project is underway to prioritize these compounds according to: 1) the degree of potential exposure, 2) known or potential health risks, 3) process- and mission-specific determination of sources of contamination, and 4) preliminary evaluation of mission performance degradations associated with compound contaminant or substitution. An effort is underway to establish a comprehensive database making use of all available national and international data in order to provide a basis from which to evaluate both the impact and the likelihood of long term or transient exposure to these agents. The database will define projected capabilities of Space Station Freedom from early assembly phase through man-tended and permanently-manned capability, previous knowledge of the lunar base environment, and the limited data available from the Viking mission for the Mars environment. This information will then form the basis for mitigation measures including: 1) future process modification or substitution, 2) special provisions for compound containment or use restrictions, 3) re-evaluation of current exposure standards, and 4) reprioritization of information needs (e.g., toxicology, effects on human performance, or re-evaluation of alternative-process mission requirements).

Ecological Systems, Closed↗
PubMed1992

Efficacy and safety of carvedilol in comparison with nifedipine sustained-release in chronic stable angina.

In patients with chronic stable exertional angina pectoris, the antianginal and anti-ischemic efficacies and the safety of 25 mg carvedilol b.i.d. were compared with those of 20 mg nifedipine sustained-release (SR) in a double-blind, randomized, multicenter study. In 22 centers, 166 patients were enrolled. After washout and run-in phases with two symptom-limited seated bicycle exercise tests on placebo, eligible patients were allocated to one of the two parallel treatment groups. After 4 weeks of active treatment, an additional exercise test was performed 12 h after the preceding dose. The patients were issued diary cards to document the daily number of anginal attacks and glyceryl trinitrate applications. Symptom-limited total exercise time, time to onset of angina, and time to 1-mm ST-segment depression increased with both treatments vs. placebo baseline values. The changes were more distinct in the carvedilol group, but the between-group differences were not statistically significant. Angina symptomatology during daily life and glyceryl trinitrate consumption were markedly improved by each treatment. Adverse events on treatment, particularly those correlated to vasodilation, were less frequent in the carvedilol group.

Adrenergic beta-Antagonists↗
PubMed1991

Treatment of chronic stable angina with carvedilol in comparison with nifedipine s.r.

Carvedilol 25 mg b.d. was compared with nifedipine s.r. 20 mg b.d. for subchronic treatment of patients with chronic stable angina. After washout and placebo run-in, 163 patients were randomly and double-blindly allocated to one of the two treatment groups. Two symptom-limited seated bicycle exercise tests were performed on placebo in order to confirm stable baseline conditions. After 4 weeks of active treatment, a further exercise test was performed in the morning, 12 h after the preceding dose. Diary cards were kept by the patients throughout the trial in order to record angina attacks and glyceryl trinitrate consumption. Carvedilol seemed to be somewhat more effective than nifedipine s.r. for improving exercise tolerance and exercise time to onset of angina and 1 mm ST-segment depression. Although there were highly statistically significant differences vs placebo, the two treatment groups did not differ significantly. No difference between treatment with carvedilol and nifedipine s.r. was found regarding angina symptoms and glyceryl trinitrate consumption during daily life. Adverse events were less frequently reported in the carvedilol group than in the nifedipine group. Generally, however, both agents were well tolerated. Carvedilol therapy for chronic stable angina seems to be both efficacious and safe.

Adult↗
PubMed1991

Ulcer relapse rates following initial treatment with bismuth subnitrate as compared with cimetidine respectively.

As part of an open clinical trial, 18 out of 23 (78%) patients were treated with bismuth subnitrate (3 x 700 mg/d) and 15 out of 25 (60%) patients were treated with cimetidine (1 x 800 mg/d) to cure peptic ulcers linked with H. pylori, as ascertained following an endoscopic examination. All patients underwent continued observation after complete healing on completion of four weeks of acute treatment. In order to determine the effect of the initial treatment on the rate of relapse, all patients were asked to return for a check-up to establish any relapse, 6 and 12 months following completion of treatment. Gastroduodenoscopy was performed where a recurrent ulcer was suspected. An immediate control examination was carried out if acute symptoms occurred between the controls. In cases of suspected ulcer recurrence, and endoscopic examination was carried out and biopsy specimens were taken in order to detect H. pylori by biochemical and histological tests. In the bismuth group, three relapses (17%) were endoscopically verified 19 to 34 weeks after completion of treatment; 2 patients showed H. pylori positive results. Of the cimetidine group, 6 patients (35%) suffered a recurrent ulcer from the 9th to the 34th week following completion of the acute therapy. Five out of the six patients were H. pylori-positive. A comparison of relapse rates between the two groups was of no statistical significance. Compared with the initial H2 receptor antagonist treatment, there was a distinctly lower relapse rate in patients who were initially treated with bismuth subnitrate.

Adult↗
PubMed1990

[Evaluation of the cost-efficacy ratio of Pall BB 22 15 filters for the bacterial protection of anesthesia circuits].

The aim of this study is to assess wether the use of the bacteriological filter Pall BB 22 15 placed on the Y piece of the anesthesia equipment decreases contamination and furthermore to evaluate the cost of this practice versus changing anesthetic circuits after every patient. Randomized trials are conducted with three "Engström" machines in three cardiac surgery operating rooms. The Y pieces were examined with qualitative and quantitative bacteriological analysis. Use filters is less expensive than changing circuit for each patient for a comparable efficacy.

Air Microbiology↗
PubMed1989

A placebo-controlled comparison of the efficacy and tolerability of picumast dihydrochloride and terfenadine in patients with seasonal allergic rhinitis.

Of 99 evaluable patients with seasonal allergic rhinitis, 33, 35, and 31 were treated with picumast dihydrochloride (3,4-dimethyl-7-[4-(4-chlorbenzyl)piperazine-1-yl]propoxycoumar in dihydrochloride) 1 mg, terfenadine 60 mg, and placebo, respectively, twice daily for 3 weeks. After 7 days' treatment physicians' assessments of symptomatic improvement showed that the effects of the two active drugs were similar and significantly superior to those of placebo. Some further improvement occurred over the remainder of the study, with no significant differences in efficacy appearing between picumast dihydrochloride and terfenadine. After 2 and 3 weeks of treatment the efficacies of both picumast dihydrochloride and terfenadine were "very good/good" in over 90% of patients. The tolerability of all three treatments was classified as "very good" in 60% to 70% of patients. Physicians were prepared to represcribe the study medication in about 90% of patients given picumast dihydrochloride or terfenadine compared with 52% administered placebo. Similar assessments performed by the patients generally agreed with these results. Withdrawal due to lack of efficacy occurred in 13, 2 and 0 patients treated, respectively, with placebo, terfenadine, or picumast dihydrochloride. Few adverse effects were reported. It is concluded that picumast dihydrochloride offers a comparable alternative to terfenadine in the treatment of seasonal allergic rhinitis.

Adult↗
PubMed1989

Efficacy and tolerability of picumast dihydrochloride in comparison with placebo in asthmatic patients.

In a randomized double-blind study, 107 patients with extrinisic, intrinsic or mixed bronchial asthma and impaired lung function received either picumast dihydrochloride (3,4-dimethyl-7-[4-(4-chlorobenzyl)piperazine-1-yl]propoxycoumarin dihydrochloride) 1 mg or placebo twice daily for 6 weeks after a 2-week placebo phase. Patients given picumast dihydrochloride demonstrated significant improvements compared with baseline in morning and evening peak flow and asthmatic symptoms like morning tightness, cough, dyspnoea, obstruction, number of asthma attacks during night and day, sum of asthmatic symptom scores, in vital capacity and Tiffeneau index, and a significant reduction of inhaled adjuvant medications. In contrast, placebo recipients improved significantly only in daytime asthma attacks, obstruction, sum of symptom scores, and Tiffeneau index. The differences between the picumast dihydrochloride and placebo groups significantly favoured picumast dihydrochloride for improvements in mean number of daytime asthma attacks, morning tightness, aerosol use and sum of symptom scores. Adverse reactions were minor and infrequent; no tiredness occurred with picumast dihydrochloride. Tolerability of both picumast dihydrochloride and placebo was rated as "good" to "very good" by patients and physicians.

Adult↗
PubMed1989

Acceptability, safety and efficacy of picumast dihydrochloride on long-term use in patients with perennial bronchial asthma.

104 adult patients with predominantly extrinsic perennial asthma who were maintained on bronchodilator or glucocorticoid therapy, were entered into a one-year open study designed to evaluate the efficacy, safety and acceptability of picumast dihydrochloride (3,4-dimethyl-7-[4-(4-chlorobenzyl)piperazine-1-yl]propoxycoumarin dihydrochloride) (2 mg twice daily). 74 patients completed the 12-month treatment period and a further 18 (total 92) were followed up for at least 2 months. Adverse drug reactions were reported in 14 patients and 5 of them were withdrawn from the trial for only non serious reactions. 12 patients were excluded from the analysis of efficacy because they dropped out early and no sufficient data were available for a judgement. Although this was an open study, analysis of diary card measurements and clinical assessments indicate that picumast dihydrochloride could represent a new and effective prophylactic therapy in the long-term management of bronchial asthma. Picumast dihydrochloride improved forced expiratory volume in 1 s (FEV1), peak flow and subjective asthmatic symptoms in 51%, 64% and 70% of the patients, respectively. 92% of those who participated in this study were willing to take the study drug again.

Adult↗