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Biomedical subjects

A Wilke

Publications and source records attributed to A Wilke.

At least 73 records · Page 4Linked to original sources
PubMed1990

[Lung function diagnosis using multi-frequency oscillometry with reference to lung volume].

The ranking of various oscillometry parameters was to be tested in patients with a broad spectrum of disturbances of pulmonary function, objectified by body plethysmographic and technical oesophageal pressure measurement of the respiratory resistance, lung volumes and lung elasticity. For this purpose the oscillatory resistance Rfo and the phase angle phi were measured at 8, 12 and 16Hz and phi was measured as it changed, depending on the lung volume V. It was found that enhanced respiratory resistance values are satisfactorily represented by Rfo for the purposes of preliminary and basic diagnostics. Besides, enhanced Rfo values are markedly dependent on the frequency, phi being shifted to negative values. Difference between Rfo values at 8 and 16 Hz (delta R8-16) less than 0.7 hPa/l/s phi greater than or equal to -10 degrees can be considered as being still normal with the employed measuring principle and are a valuable supplement for assessing the degree of obstruction. The difference between phi in the medium respiratory position and at 90 or 100% total capacity (delta phi) is less than 5 degrees during slow inspiration in 80% of the patients suffering from emphysema. In 80% of the persons with healthy lungs and those suffering from fibrosis there is an inspiratory negativation of phi (delta phi greater than 5 degrees) so that the phi-V relationship appear suitable for distinguishing patients with restricted vital capacity in respect of emphysema and fibrosis. Patients suffering fron fibrosis differ from healthy subjects by slightly more negative phi values. The borderline values for delta R8-16, phi and delta phi were confirmed in two further series of examinations on children and adolescents.

Adult↗
PubMed1990

[Ergo-oxytensiometry--recommendations on methodology and evaluation].

The purpose of this review is to provide recommendations for measurement and interpretation of ergooxymetry relevant to performance in out-patient departments. Ergooxymetry is the most suitable method for assessment of physical work capacity. The examination demands a distinct indication and knowledge of contraindications. On the basis of a standardized 3-step loading (VO2 = 1,050 ml/min, VO2 = 1,350 ml/min, VO2 = 1,650 ml/min; incremental loading without breaks; 6 min for each loading step) criteria for interpretation are given for PaO2, heart rate, arterial blood pressure and FEV1 respectively ROS.

Adult↗
PubMed1989

Role of Ca2+ and Mg2+ for endothelial permeability of water and albumin in vitro.

The permeability of endothelial monolayers grown on a polycarbonate filter membrane and continuously exposed to a hydrostatic pressure of 10 cm H2O was studied. The ionophores A23187 and ionomycin dose dependently (0.1-10 microM) enhanced the hydraulic conductivity of sealed endothelial cell monolayers 10 to 15-fold, at the same time the reflection coefficient of albumin dropped from 0.75 to 0.2. The effects of A23187 were dependent on extracellular Ca2+. In the absence of Ca2+, however, Mg2+ could substitute for Ca2+. Phase contrast- and scanning electron-microscopy showed that the A23187-induced effects were accompanied by gap-formation in the intercellular clefts. These gaps probably are the sites which allowed enhanced fluid exchange. Ionophore-induced effects on permeability could be modified by antagonists of calmodulin function and of arachidonate liberation and metabolism. The data suggest that alterations of endothelial Ca2+-homeostasis induce metabolic events which result in an increased permeability of an endothelial monolayer.

Albumins↗
PubMed1989

[Theoretical and experimental studies of the diagnostic relevance and comparability of mechanical oscillation parameters].

The practical application of the forced oscillation technique for the analysis of the mechanics of respiration is hampered by the fact that the measured frequency-dependent impedance values R(f) and X(f) cannot be related directly to the parameters airway resistance Raw and pulmonary compliance CL. Furthermore, various derived oscillatory parameters are employed which are not directly comparable even with one another. In order to be able to estimate the diagnostic relevance and comparability of the impedance curves R(f) and X(f), their form-specific characteristics R = R(5)-R(20) and X(5), as also the equipment-specific parameters Ros (Siregnost FD5) and Rfo (custo vit), the relationships of these oscillatory parameters to Raw and CL were simulated in a structural model of the respiratory system, and tested in the real system. It was shown that already from frequencies of f greater than 10Hz upwards, R(f) no longer reacts to an increase in resistance in the peripheral region of the lung, and at 20 Hz indicates only the upper airway component of a global obstruction demonstrated body-plethysmographically with Raw. The diagnostic information on peripheral airway obstruction is contained in both components R(f) and X(f) of the respiratory impedance; with increasing obstruction and increasing frequency, it progressively reverts to the X(f) curve. Therefore, by including X(f) in the resistance evaluation for the parameters Ros and Rfo, the underevaluation of R(f) as compared with Raw can in part be compensated for, although an overe stimation at low Raw values with Ros and a large scatter of the Rfo values in the case of large Raw figures has to be accepted.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1989

[Practical experiences with 2 oscillatory measuring procedures, Siregnost FD 5 and custo vit, in the assessment of chronic airway obstruction].

In patients with chronic obstructive airway disease, comparative examinations using body plethysmography were performed with a view to evaluating the effectiveness of two forced oscillation techniques, fixed-frequency and poly-frequency techniques in estimating disorders of respiration mechanics. At slight and moderate elevations in bronchial flow resistance, a better agreement was found between the custo vit resistance figure and body plethysmography. A differentiation of healthy subjects from patients with low-grade obstruction by means of the FD 5, requires the establishment of the phase angle (phi), too, while in the case of the custo vit unit, this is possible by demonstrating the frequency dependence of the impedance. Patients with more severe disease with secondary emphysematous changes, reveal a clear difference between the phase signal (psi) primarily measured on the FD 5, and the phase angle. Forced oscillation usefully supplements spirometery in the respiratory basic diagnostic work-up employed through-out treatment. Fixed-frequency techniques require the determination of the phase angle for assessment of peripheral obstructions; the advantage of the poly-frequency technique can be seen in the largely specific demonstration of the frequency dependency of the resistance.

Airway Resistance↗
PubMed1989

[Oscillometric differentiation of lung fibrosis and lung emphysema].

In three groups of healthy subjects and patients with pulmonary fibrosis or pulmonary emphysema, the secondary periodical oscillatory phenomena observed under conditions of normal breathing and a slow VC manoeuvre on the Siregnost FD 5 were broken down into a volume- and a flow-synchronous component, as also a third component with no correlation with either volume or flow, and which can be observed in the primary parameters Ros and psi, as also the secondary parameters Rre and phi. While both fibrotic patients and healthy subjects revealed a volume-inverse phase behaviour, patients with pulmonary emphysema revealed a volume-proportional phase behaviour. This difference in volume dependence is explained by the difference in elastic recoil in patients with fibrosis as compared with those suffering from emphysema, and the associated different influence on the filling of the lungs with air and blood.

Adult↗
PubMed1989

[Report of a trial of polyfrequent oscillo-resistometry with the custo vit equipment].

With the aim of determining the significance of the principle of the multi-frequency forced oscillation technique employed by the custo vit to determine the airway resistance, measurements were performed on a number of test subjects, employing a unit available with three different software modifications. A comparison with the resistance values obtained with other equipment (whole-body plethysmograph, Siregnost FD5), revealed the diagnostic usefulness of the technique of frequency-dependent resistance. It was also confirmed that the phase angles, also obtainable with the custo vit, play a considerable role in the significant differentiation of the degree of obstruction. The differences in comparison with other methods are critically examined, and proposals made for a further improvement of the forced oscillation technique employed by the custo vit.

Airway Resistance↗
PubMed1988

Bacterial exotoxins and endothelial permeability for water and albumin in vitro.

Effects of Staphylococcus aureus alpha-toxin and Pseudomonas aeruginosa cytotoxin on the permeability of an endothelial monolayer were studied. Porcine pulmonary artery endothelial cells were grown on a polycarbonate membrane, mounted in a chamber, and exposed to a continuous hydrostatic pressure of 10 cmH2O. On application of this trans-endothelial pressure, endothelial monolayer became "sealed," i.e., the filtration rate for water decreased and the reflection coefficient for albumin increased, reaching a plateau after 1-2 h. Sealed monolayer had a hydraulic conductivity of 2.1 X 10(-6) cm.s-1.cmH2O and an albumin reflection coefficient of 0.73. Permeability of the monolayer was increased on addition of an excess of EDTA and reversed on readdition of calcium. Within 60-90 min after addition of 1 microgram/ml alpha-toxin, the filtration rate increased 75-fold, and the albumin reflection coefficient dropped to 0.20. These changes in permeability were accompanied by cell retraction and formation of large intercellular gaps between endothelial cells. Effects of alpha-toxin were abolished by preincubation with neutralizing antibodies and by inhibitors of calmodulin function. Pseudomonas aeruginosa cytotoxin (25 and 50 micrograms/ml) also increased the permeability of the endothelial monolayer, but it was only about one-third as effective as alpha-toxin.

ADP Ribose Transferases↗
PubMed1988

[Theophylline-retard preparations: relation between drug liberation in vitro and their behavior in the human body].

Using theophylline retard preparations, the course of drug concentration in serum can be read from the speed of drug liberation estimated in vitro. For preparations with a strong retard effect we have to calculate a diminished bioavailability. The management of therapy in the therapeutical range and without side effects is possible with preparations with nearly complete bioavailability, nevertheless theophylline remains a problem drug. Firstly, the interindividual deviations are excessive great, with the usual standard dose caused by the different body mass and by the different biotransformation. Secondly, the "Food induced dose dumping" is appearing if taking drug and food is unsuitably coupled. Summarizing the present results, several steps for further optimization of therapy with theophylline retard preparations are proposed.

Administration, Oral↗
PubMed1988

[Therapy of asthma with theophylline preparations].

Theophylline, 1.3-dimethylpurindione-(2.6), is a common component as well of the basic treatment of obstructive lung disease as of the emergency therapy of asthma. Until now, the mode of action of the bronchodilating effect is not elucidated. Probably, the antagonistic action upon adenosine plays a central role. The clearance of theophylline is decisive for the serum level. It varies inter- and intraindividually, depending upon different factors, e. g. simultaneous application of other drugs, coexisting diseases, and circadian rhythms. Slow-release preparations are a progress in the basic treatment of bronchial asthma and chronic obstructive bronchitis. Among other items, they are especially advantageous in the treatment of bronchial obstructions during night-time. Theophylline-ethylendiamine (aminophylline) can be given intravenously and thus is the drug of choice in severe attacks of asthma. For optimal therapeutic effects, serum levels between 8 and 20 micrograms/ml are necessary. Side effects are observed mainly with serum levels above 15 micrograms/ml, concerning gastrointestinal tract, central nervous system, and cardiovascular system. Mild side effects are frequent. The most serious adverse reaction are epileptiform reactions. In perspective, by differentiation of adenosine-receptor-subtypes, the development of new xanthine-derivatives with most favourable action could be feasible.

Asthma↗
PubMed1988

[Clinical use of theophylline retard Oranienburg].

Theophylline retard "Oranienburg" has been applied in mild and intermediate forms of bronchial asthma as monotherapy (n = 40), and in severe forms of the disease in combination with other antiasthmatics (n = 21). With a dose of 560 mg twice daily the drug showed effective antiasthmatic activity which was especially evident from the possible reduction of corticosteroid requirement. The relative high rate of side effects from the drug can be lowered by stepwise increase and individual adjustment of the dose. In general, treatment should start with 2 tablets per day, given with 12 hours interval. To preserve the slow-release action, tablets should not be cut in half. In individual cases, determination of serum level of the drug may be required. The narrow therapeutic margin and the influence of numerous factors upon the clearance of theophylline require a thorough dosage and observation of the patients. Thus, the favourable properties of the preparation (lasting serum levels, improved compliance by patients) can be fully used.

Adrenal Cortex Hormones↗
PubMed1987

[Methodological studies of the metabolism-oriented determination of the lysine requirement in broiler chickens. 1. Influence of the lysine content of the diet on the lysine oxidation rate in short-term food withdrawal before 14C-lysine injection].

For the estimation of lysine requirement 128 male broiler chickens were used at an age of 7 to 21 days posthatching. They received a lysine deficient diet composed of wheat and wheat gluten. To this basal diet L-lysine-HCL was supplemented successively resulting in 8 lysine levels ranging from 5.8 to 23.3 g lysine per kg DM (2.2 to 8.7 g lysine per 16 g N). At the end of the two-week feeding period of the experimental diets 14C-lysine was injected intravenously 1.5 and 5.5 hours after feed withdrawal. During the following 4 hours the excretion of CO2 and 14CO2 was measured. This 4 hours absorption period for 14CO2 was regarded as sufficient according to a preliminary experiment. The highest daily gain of 21.5 g was observed in animals fed 13.3 g lysine/kg DM. Lysine concentrations exceeding 18.3 g/kg DM depressed body weight gain. The CO2-excretion was not influenced by lysine intake. The 14CO2-excretion was low with diets low in lysine content and increased 3 to 4 times with diets meeting the lysine requirement. Based on measurements 1.5 to 5.5 hours after feed withdrawal the saturation value for lysine was reached at 13.3 g/kg DM. This value was lowered (10.8 g/kg DM), however, if the estimation was carried out 5.5 to 9.5 hours after feed withdrawal. These results suggest a higher metabolic lysine requirement during the earlier period after feed intake. Both, reduced weight gain and non linearity in 14CO2-excretion with diets exceeding a lysine content of 18.3 g/kg DM indicate a limited capacity of the organism to degrade excessive lysine. According to the results of this experiment for broiler chickens 3 weeks posthatching a lysine requirement between 10.8 and 13.3 g/kg DM (27% CP and 660 EFUhen/kg DM) was concluded. The range of estimated requirement data could be narrowed by the use of diet with other lysine content.

Animals↗
PubMed1987

[Methodologic studies on the metabolically-oriented determination of lysine requirements in broiler chickens. 2. Effect of the lysine content of the diet on the lysine oxidation rate in a 15-hour feed withdrawal before 14C-lysine injection].

This experiment was designed to narrow the estimated range for lysine requirement of broiler chickens determined by isotopic techniques. In addition the influence of a long-term feed withdrawal previous 14C-lysine-injection on the lysine catabolism was investigated. 120 male broiler chickens 7 to 21 days posthatching received a diet based on wheat and wheat gluten. Lysine content was varied from 8.3 to 16.0 g/kg DM (3.2 to 6.3 g/16 g N) at 8 levels by supplementing the basal diet with L-lysine-HCl. After the feeding period animals of each group were labelled with 14C-L-lysine by intravenous injection 5.5 and 15.5 hours after feed withdrawal, respectively. During the following 4 hours the excretion of 14CO2 and CO2 was measured. Highest body weight gain was observed in the group with 13.8 g lysine/kg DM. In case of 14CO2 excretion measurements starting 5.5 hours after feed withdrawal an increase of 14CO2 excretion was observed if the lysine content of the diet exceeded 11.6 g/kg DM. This estimated range for lysine requirement (11.6 to 12.7 g/kg DM with 26% CP in the DM) was lower compared with the lysine requirement estimated by the growth curve (12.7 to 13.8 g/kg DM). This discrepancy could be explained by the fact that the results of the metabolism oriented determination of lysine requirement represent the requirement at the actual age, while the feeding experiment reflects a mean lysine requirement of the previous period of 14 days. If the animals were labelled with 14C-lysine 15.5 hours after feed withdrawal no clear response in 14CO2 excretion and specific radioactivity of CO2 on the dietary lysine content was observed.

Animal Feed↗
PubMed1987

[Methodologic studies on the metabolism-oriented determination of methionine requirements of broiler chickens].

In a preliminary experiment the time course of 35S-excretion following a single injection of 35S-methionine in male broiler chickens was measured for 5 days. Within 2 days 65 to 69% of the amount of 35S excreted during the whole 5-day-period were recovered. Therefore, in the main experiment excrements for 35S measurement were collected only 2 days. During the main experiment starting 7 days posthatching 48 male broiler chickens received diets based on peas and wheat. The basal diet was supplemented with DL-methionine at 8 levels increasing the methionine content from 3.3 to 7.5 g/kg DM or 1,51 to 3.42 g/16 g N and the content of sulphur containing amino acids varied from 6.8 to 11.8 g/kg DM or 3.11 to 5.02 g/16 g N, respectively. Daily body weight gain was followed up to day 30 posthatching and N-balance was estimated during the 21st to 26th day posthatching. Up to day 26 a methionine content of 3.9 g/kg DM was sufficient for maximum weight gain. However, during the last period of the experiment highest weight gains were observed in animals receiving diets with 4.5 or more methionine/kg DM. Highest N-retention (1.2 g N/d) was measured if the diet contained 3.9 g methionine/kg DM or more. At day 28 posthatching 35S-methionine was injected intravenously and the subsequent 35S-excretion was measured. The 35S-excretion started to increase at a methionine content in the diet of 4.5 g/kg DM and continued to rise up to the highest methionine content of 7.5 g/kg DM. The metabolism oriented methionine requirement determination indicates for male broiler chickens at the beginning of the 5th week posthatching a methionine requirement of 3.9 to 4.5 g/kg DM (1.78 to 2.05 g/16 g N) and a requirement of S-containing amino acids of 7.4 to 8.0 g/kg DM (3.38 to 3.65 g/16 g N). The method used is potential in studying the age-dependent changes in methionine requirement.

Animal Feed↗
PubMed1987

Ambroxol increases the choline but not fatty acid incorporation into lung phospholipids in experimental lung disorders.

Ambroxol, a drug capable of elevating the phospholipid content in healthy rabbit lungs, was tested on two models of experimental lung injury, lung changes in sepsis induced by a peritonitis and in bromcarbamide intoxication. The phospholipid content of the lungs and the synthesis of the individual phospholipids phosphatidylcholine (PC) and sphingomyeline were measured in vitro by incubation of lung slices with labeled phospholipid precursors. Influenced by the drug, the phospholipid content increases to 132% in the peritonitis experiments and to 111% in the bromcarbamide experiments. The peritonitis experiments show the increase in phospholipid synthesis to result from an enhanced choline incorporation into PC up to 192% and into sphingomyeline up to 630%. The values for the bromcarbamide experiments are 411% for PC and 485% for sphingomyeline, respectively. There was no statistically significant difference in the incorporation of fatty acids in the treated and untreated animals. We conclude that ambroxol possibly stimulates the phospholipid synthesis in injured lungs by stimulating the choline phosphatcytidyltransferase, but not the incorporation of fatty acids into PC in those lungs. These findings may be important to the surfactant system of the lung consisting mainly of PC.

Ambroxol↗
PubMed1987

[Pharmacokinetic and therapeutic monitoring in the development of theophylline-retard preparations].

After oral application of a sustained release preparation of aminophylline (2 tabl. of 350 mg b. i. d., i. e. a total doses of 1400 mg) the doses related to body mass and the average individual concentration of theophylline in serum are varying about 50% and more of the mean. The mean individual concentration in serum changes proportionally to the doses related to body mass. Furthermore two groups of patients with different theophylline concentrations can be distinguished. The reason is probably a different biotransformation. The mean concentration of theophylline in serum rises to a maximum at the 5th d. From the 8th to the 29th d of treatment the range of concentration is nearly constant. Reaching the steady state is probably overlapped by processes of enzyme induction. In about 60% of the patients the concentrations of theophylline are in the therapeutical range. When adaptation of doses to body mass takes place a higher portion can be expected. To achieve all therapeutical possibilities it is necessary to correct the doses also for the different types of biotransformation.

Biotransformation↗