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Biomedical subjects

W Erhardt

Publications and source records attributed to W Erhardt.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Does the calcium antagonist verapamil protect from myocardial damage during tocolysis with beta-sympathicomimetics? (author's transl)].

Under general anaesthesia nine mongrel dogs were first injected with fenoteral 0.06 mg/kg/per minute and later with fenoteral 0.06 mg/kg/per minute and verapamil 2 mg/kg/per minute. A microtip manometer was placed into the left ventricle and cardiac pressures continously monitored. The resulting pressure curves were used in micro-computer to calculate the cardiac pressure parameters including the inotropic measurements and the myocardical oxygen consumption. The intravenous infusion of the beta-mimetic fenoterol resulted in marked increase of the cardiac rate and contractility as measured in the different measurement of the ionotrophy. A corresponding increase of the myocardical oxygen consumption was found. The addition of the calcium antagonist verapamil did have no influence of the measured parameters. A protective effect of the calcium antagonist on the myocaridium was excluded in the animal experiment. A protective effect during tocolysis with beta-sympathicomimetics cannot be expected because of the expected low serum concentrations.

Animals↗
PubMed1980

[Examination of plasminogen-activators and plasmin-inhibitors in maternal and fetal rat-lung-tissue after administration of DL-carnitine-hydrochloride (author's transl)].

In the formation and resolution of fibrinous pulmonary hyaline membranes of the type occurring in perinatal respiratory distress, the plasminogen activators and plasmin inhibitors contained in the tissue assume central importance. Carnitine does not change plasminogen activator activity and reduces the plasmin inhibitor content in the foetal rat lung. Hence, no inhibiting action on local fibrinolytic processes can be established for carnitine.

Animals↗
PubMed1980

[Pharmacologic influencing of fetal phospholipid synthesis. Part IV: influencing the DPL(dipalmitoyl-lecithin) content of fetal lung by betamethasone (author's transl)].

Dipalmitoyllecithinic (DPL) is the quantitatively largest and most active portion of the surfactant system. Hence only a quantitative DPL determination allows a relevant statement of fetal lung maturity. The antenatal prophylaxis of RDS should result in an increase of the DPL-level in a fetal lung. A new gaschromatographical method for determination of DPL was developed. The results were secured by gaschromatography-mass-spectrometry-couplings. After treatment with betamethasone an increase of the relative DPL-amount in fetal rat lung lecithin species was found, but not an increase of the lecithin-level in the lung-tissue. Corticosteroids probably induce transesterification of the lecithins.

Animals↗
PubMed1980

[Extracorporeal pig liver perfusion in normo- and moderate hypothermia (author's transl)].

32 allogeneic extracorporeal pig liver perfusions were performed for a period of 3 hours to examine the viability of the isolated liver. The perfusion apparatus consisted of 3 independently regulated pumps and of a semiautomatic flow regulation by a capacitive level transducer. The bile secretion alone gives a rough estimation only when external influences like the temperature are taken into consideration. The oxygen consumption correlated to pressure and flow is a suitable parameter indicating the viability of the extracorporeally perfused liver. By combining these bed-side parameters we were able to determine the functional capacity of an isolated liver properly. Under moderate hypothermia (34 degree to 35 degree C) the oxygen consumption falls by 25%, while the bile secretion falls by 487.8%. The success of an extracorporeal liver perfusion will depend on achieving normothermal conditions. For clinical use one may concentrate on these quick and easy bed-side parameters. Because other tests of viability like clearance methods or assays of metabolites are very time-consuming they are of little value in the immediate control of a running perfusion.

Animals↗
PubMed1980

[Liquid shifts in the lung under fenoterol and verapamil. Experimental study on the origin of pulmonary oedema under tocolysis. III (author's transl)].

The question of the causal relationship between tocolysis and pulmonary edema has been unresolved up till now. Eight mongrel dogs were given infusions of Fenoterol (0.06 mcg/kg/min) and later of Fenoterol (0.06 mcg/kg/min) and Verapamil (2 mcg/kg/min). In the case of infusion of Fenoterol alone measurements by the thermo-dye-technique showed massive shifts of lung fluids from the intravascular to the extravascular space corresponding to interstitial edema. The addition of Verapamil induced no further changes. The intrapulmonary haemodynamical overload by increased cardiac output and pulmonary arterial pressure which we measured after infusion of Fenoterol must be regarded as the main cause of the shifts in fluid volumes. They seem to be amplyfied by central nervous-, metabolic- and localized toxical effects of the betamimetic drug. A direct cardiac cause as well as serious changes in electrolytes and colloidosmotic pressure could be excluded.

Animals↗
PubMed1980

[Respiratory and circulatory parameters under fenoterol and verapamil. An experimental study on the origin of pulmonary oedema under tocolysis. II (author's transl)].

In order to explain the development of pulmonary edema it is, in addition to determine shifts of lung fluids, indispensible that changes in the circulatory system be evaluated as well as changes in the breathing function by means of analysis of blood gases and acid and base status. The relevant parameters were continuously registrated for 8 anaesthesized mongrel dogs after the infusion of Fenoterol (0.06 mcg/kg/min) and later of Fenoterol (0.06 mcg/kg/min) and Verapamil (2 mcg/kg/min). A cardiac disfunction and irregularities in the ventilation process in the lung could be excluded. The proven changes such as an increase in cardiac output with increased venous backflow, and intrapulmonary shunt-formation as well as acidosis after an infusion of the betamimetic drug are to be regarded among the causes of a development of pulmonary edema. Verapamil produced no further changes in the evaluated parameters.

Animals↗
PubMed1980

[Method for measuring physiological changes under fenoterol and verapamil. An experimental study on the origin of pulmonary oedema under tocolysis. I (author's transl)].

Fluidshifts in the lung seem to play an important role in labour inhibition with fenoterol and verapamil. Therefore the experimental procedure for an investigation of these drugs is discussed in detail. The Thermo-Dye-Technic is used for quantitating pulmonary extravascular water. Moreover methods for monitoring pulmonary and systemic hemodynamics, bloodgases and acid-base-balance, metabolic parameters and the realization of the experiment are described.

Animals↗
PubMed1979

[Therapy of Amanita phalloides poisoning. Results of clinical and experimental studies].

On the basis of experimental and clinical results evidence accumulates that supportive therapy is still the milestone in the therapy of death cap poisoning. Today the letality is 20%. The main cause of the intoxication are the amatoxines which inhibit DNA dependent RNA Polymerase II or B. Parts of the supportive therapy are: diuresis with 150--200 ml urin/hour, careful corrections of disturbances in electrolyte and acid-base-metabolism, oral administration of charcoal and oral gut sterilization. In spite of a multitude of experimental and clinical reports on the effectivity of Penicillin G, thiocticacid and steroids there are no controlled studies to demonstrate the advantage of one regimen over the other. The time course of resorption and excretion of amatoxines clearly shows that hemoperfusion and/or hemodialysis are only of value if applied within the first 24 hours after poisoning. At this time neither anamnestic nor biochemical data give any clues to the probable course of the disease. Heterologous baboon liver perfusion may be lifesaving in coma hepaticum grade IV, but the small amount of cases so far does not yet allow any comments on its effectivity.

Amanita↗
PubMed1979

Fluorescein angiography and changes in aqueous humor protein after argon laser photomydriasis in rabbits.

In brown-eyed and blue-eyed rabbits, irises treated with argon laser photomydriasis (ALP) were studied by using fluorescein angiography and by evaluating the aqueous humor protein concentration. The following results were obtained. Immediately after ALP, a breakdown of the blood-aqueous barrier is demonstrated by a marked influx of fluorescein into the ciliary processes and into the anterior and posterior chambers. The dye flow into the aqueous humor decreases to normal values within 3 days. There is no fluorescein leakage from laser impacts themselves. Peripupillary capillary loops are permanently occluded, but in a few cases, recanalization occurs. Neovascularization did not occur during 56 days of observation. ALP initially leads to a six- to eightfold increase in normal aqueous humor protein concentration, which decays to normal values within 3 days.

Animals↗
PubMed1979

Experimental studies on the use of microwaves for the localized heat treatment of the prostate.

High frequency tumor therapy requests heating of a well defined area, whereas the surroundings should be unaffected. This sort of therapy should be more tolerable than a whole body heating. For this purpose a new developed microwave applicator (433.9 MHz) for local heat application was tested in animals. Using this rectally insertable applicator the prostate of dogs were irradiated. The temperature of the rectum, the urethra and the prostate were measured and recorded using specially developed thermistor probes. The effect of hyperthermia on the prostate and the surrounding tissue was analyzed macroscopically and micromorphologically. It was shown that local heating of the prostate of dogs is possible. The induced damages of the prostate and surrounding tissue is not severe enough to be untolerable.

Animals↗
PubMed1979

[Anesthsiological experiences in experimental surgery].

The paper reports experience with methods of anaesthesia in rabbits, rats, mice, guinea-pigs, pigs, sheep, baboons, dogs and cats. Special problems of handling, mode of injection and intubation are discussed. A comprehensive survey of literature provides further information about the proposed patterns of anaesthesia and informs about other anaesthetic methods, not practised by the authors.

Alcuronium↗
PubMed1979

[Diaplacental transfer of verapamil in guinea pigs (author's transl)].

Verapamil (1--50 mcg/kg/min) was given to guinea pigs by intravenous infusion for 30 minutes. The average clinical dosage amounts to 1 (0,5--2) mcg/kg/min. At doses of 1--10 mcg/kg/min we could not find pharmacologically effective concentrations of verapamil in plasma, although concentrations in mother rose corresponding to administered doses. Only at dosage 50 mcg/kg/min we found comparatively to the mother low, but clearly measurable concentrations also in fetal plasma. That means: Verapamil, administered to guinea pigs--hemomonochorial placentation like man--in dosage, given for tocolysis does not appear in fetal plasma with pharmacologically effective concentration.

Animals↗
PubMed1979

[External mechanical cardiac stimulation. Methods and possible application (author's transl)].

External mechanical cardiac stimulation represents a noninvasive method for myocardial stimulation which has significant advantages of external electric stimulation. This paper describes a new method using pressure- and shockwaves for transthoracic cardiac stimulation. On the basis of animal experiments the potential value of external mechanical stimulation for emergency medicine and various other therapeutic and diagnostic procedures are discussed.

Animals↗
PubMed1979

[Induction of fetal lung-maturity. Part III: surfactant-parameters in amniotic-fluid and fetal lung].

In animal experiments we determined surfactant-specific parameters of premature fetal lungs and of samples of amniotic fluid taken fromthe same animal, and compared them with each other. These parameters were, among others: total phospholipids, lecithine and palmitic acid. In these experiments, 75 gravid Wistar rats were treated with NaCl (controls) or drugs in clinically relevant doses for stimulating the fetal synthesis of phospholipids like betamethasone, bromhexine metabolite VIII and D-L-carnitine hydrochloride. A relation between the amniotic fluid and the fetal lung with regard to the quantity of surfactant substances was found - with a security of 95% - with the controls only. The value of amniotic fluid analysis is discussed under this aspect.

Amniotic Fluid↗
PubMed1979

[Healing of argon laser lesions of the rabbit iris (author's transl)].

Healing of perforating and low dose argon laser lesions of pigmented rabbit irides was studied by light microscopy. Low dose coagulation produced brown stained areas with fibrinous exudation of the surrounding tissue. Healing proceeded with little infiltration of leucocytes leading to an atrophic iris scar with numerous pigment macrophages. Laser iridotomies were closed within 28 days by a scar, shaped by proliferating cells and newly formed collagen fibrils. Lesions of the epithelium of the lens were demonstrated by hemalum staining of the nuclei, even in cases, when no lens opacities could be detected by biomicroscopy.

Animals↗