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Biomedical subjects

W Erhardt

Publications and source records attributed to W Erhardt.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Adams-Stokes syndrome and therapy with pacemaker implantation in a dog].

Case report concerning therapeutic pacemaker implantation in a 3 year old West-Highland-White terrier with Adams-Stokes syncopes. EKG's, X-ray-pictures, illustrations of the pulse rate and quality and oxygen measurements with a "Pulsoximeter" before and during surgery are shown. A special place takes the report of selection and control of the anesthesia in this case of a special operation. 17 references and 11 pictures.

Adams-Stokes Syndrome↗
PubMed1990

[Early postoperative intestinal motility following abdominal surgery in an animal experiment].

Gastrointestinal myoelectrical activity was registered in 6 dogs after different surgical procedures such as laparotomy, segmental resection of the jejunum and right hemicolectomy. Animals were studied in the fasted- and fed state and after pharmacological stimulation with Ceruletide. The electrical activity was recorded by means of 6 bipolar electrodes implanted along the intestinal wall. Abdominal surgery abolished normal motility in the stomach and small intestine only for a short period of time. The time for the reappearance of regularly recurring activity fronts varied with the type of the surgical procedure from 3 h after segmental resection of the jejunum to 49 h after colon resection. Severe disturbances of the BER (basic electrical rhythm) in the stomach as tachygastria and tachyarrhythmia persist even after restoration of the MMC (migrating motor complex) in the small intestine. Feeding induced a typical fedpattern but never before restoration of the MMC. Stimulation of the intestine during postoperative ileus with Ceruletide increases segmental myoelectrical activity. The period of postoperative ileus was not reduced.

Animals↗
PubMed1990

The cardiorespiratory effects of intrathecal xylazine in the conscious rabbit.

The alpha 2 agonist xylazine produced a dose-dependent decrease in mean arterial blood pressure in conscious rabbits when injected intrathecally (i.t.) through a cannula previously implanted under general anaesthesia. Intrathecal administration of 200 and 400 micrograms of xylazine produced a significant reduction in arterial blood pressure from control values (maximum depressions of 25% and 33%, respectively). There was little effect on cardiac output and arterial carbon-dioxide tension and no effect on respiratory rate, arterial oxygen tension and pulse rate. Intrathecal injection of 100 microliters of 0.9% saline had no effect. Intravenous (i.v.) tolazoline (0.5 mg/kg) abolished xylazine-induced hypotension (200 micrograms) in four rabbits. Contrast radiography revealed that 100 microliters of solution injected i.t. in anaesthetized rabbits spread distally over eight vertebral spaces. There was little rostral spread. It was concluded that xylazine-induced hypotension following i.t. injection was due to local activation of alpha 2 adrenoceptors present in the thoracic spinal cord. It is postulated that spinal alpha 2 adrenoceptors may play an important role in the hypotension recorded in animals after parenteral injection of xylazine.

Animals↗
PubMed1990

Chicken egg antibodies for prophylaxis and therapy of infectious intestinal diseases. III. In vivo tenacity test in piglets with artificial jejunal fistula.

Large quantities of specific egg antibodies can be produced with little effort by immunization of laying hens. Several antibody containing egg preparations were subjected to a tenacity test against digestive activity taking piglets with artificial jejunum fistulas as a model. Even with high doses of orally administered yolk lyophilisate no antibody activity could be found in the distal jejunum. The additional feeding of egg white, however, showed a significant protective effect on the yolks antibodies during the digestive act. No difference between egg white of immunized hens and egg white of unimmunized hens could be detected. Buffering the acidic gastric environment with sodium bicarbonate increased the antibody activity in the intestine by an average of 40%. Eggs administered in hot (70 degrees C) beef stock had higher antibody titers than eggs that were boiled for 4 minutes. Tenacity in antibodies fed in pellets was significantly lower than in powdered feed.

Animals↗
PubMed1990

[Combination anesthesia in sheep with ketamine-(fentanyl)-guaifenesin (My 301)-laughing gas-halothane].

The concept of combined anaesthesia, the centrally-acting muscle relaxant guaifenesin (My 301) in a 5% solution with ketamine (and/or fentanyl) in addition to the inhalation of nitrous oxide and halothane is based upon the principle of "balanced anaesthesia". Guaifenesin amplifies the effect of several anaesthetics, which complement one another, allowing the dosage to be decreased and thereby reducing the cardiovascular stress. To induce anaesthesia, the combination of a cataleptic anaesthetic (ketamine = Ketanest, Ketolar) and a centrally acting skeletal muscle relaxant (guaifenesin = Myolaxin, My 301) is used. Because of the risk of aspiration the animal should be intubated as soon as possible. Anaesthesia will be prolonged by the carrier gas nitrous oxide (65%, weakly analgesic)/oxygen (65%), low concentrations of halothane (1.0 to 0.6 to 0.4%, weakly hypnotic and analgesic) and by a continuous drip infusion of 5% guaifenesin (relaxing, mild analgesic and sedative). The effect of all the other anaesthetics is increased by guaifenesin. To increase the analgesia and to control the cardiovascular parameters the additional injection of ketamine or fentanyl is recommended. The recovery period is short and the general condition is good both after a lengthy anaesthesia of 9 hours (n = 32) and after anaesthesia of 2 hours. No significant adverse effects on the cardiovascular system were detected.

Anesthesia↗
PubMed1990

[Orotracheal intubation in rats].

A detailed description of the technique of orotracheal intubation under visual control in rats is given. This method was used successfully in 190 animals, the complication rate being 3.2%. The hazards consisted of laryngospasm (1.6%) and fatal bleeding (0.5%). Intubation was proved to be a safe, reliable, simple and atraumatic way to establish a patent airway in this laboratory animal.

Animals↗
PubMed1989

[Pulse oximetry--a non-invasive method for direct and continuous monitoring of oxygen saturation and pulse rate--comparative studies with blood gas analysis and hemoreflectometry in the dog, swine and sheep].

The use of pulse oximeters as a non-invasive, real time and online method for the continuous monitoring of oxygen saturation is discussed and compared to other methods like hemoreflectometry, and blood gas analysis. Analyses of linear regression show extraordinarily good correlations between all three monitoring systems. Pulse oximetry and hemoreflectometry on the one hand and blood gas analysis on the other hand sometimes show quite differing values of oxygen saturation. This phenomenon is due to the fact that the measuring methods are based on different working principles as well as it can be explained by the various hemoglobin-types. The pulse rate also measured by the pulse oximeter is nearly completely identical to the heart rate of the ECG. A slight temporal delay between the two acoustic signals is noticed and justified. Pulse oximetry seems to be superior to other oxygen monitoring systems because of its continuous noninvasive measuring technique.

Animals↗
PubMed1989

[The antagonism of ketamine/xylazine anesthesia ("Hellabrunn mixture") in wild zoo ruminants].

The ability of the antagonists tolazoline, yohimbine and the combination of yohimbine with 4-aminopyridine to reverse the effects of the xylazine-component of the "Hellabrunn mixture" (125 mg/ml xylazine and 100 mg/ml ketamine) on nondomestic zoo ruminants is discussed. Arousal time, recovery time and changes in the parameter of circulatory and respiratory functions after antagonization are shown. Tolazoline is able to antagonize the xylazine effect completely within a short time. Using a dosage of 3-5 mg/kg there is a marked negative effect on the cardio-vascular system. Yohimbine in the used dosage of 0.25-0.3 mg/kg in non-domestic ruminants did not approve in its effects. Combining yohimbine (0.25-0.3 mg) with 4-aminopyridine (0.5 mg/kg) recovery time is about 30 minutes. The negative effect on the cardio-vascular system is less pronounced compared with tolazoline.

4-Aminopyridine↗
PubMed1989

[CO2-stunning of swine for slaughter from the anesthesiological viewpoint].

For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.

Abattoirs↗
PubMed1988

Laser induced shock wave lithotripsy--biologic effects of nanosecond pulses.

Laser energy of a Nd-YAG laser (1064 nm. wave length, 8 nsec pulse duration) was directed against various tissue cultures and the urothelium of the ureter, bladder and kidney parenchyma in pigs. Single pulse energy was 50 to 120 mJ with a repetition rate of 20 Hz. Urothelium and kidney parenchyma were irradiated in seven pigs. Tissue samples were examined histologically and electron microscopically directly, two, four, eight and 12 days after irradiation. No macroscopic lesion could be found. Maximum energy caused a small 'rupture cone' of 40 micron. depth. No thermic effects or necrosis resulted, so that no harm is to be expected with unintentional irradiation during laser stone disintegration.

Animals↗
PubMed1988

[The principle of "balanced anesthesia" in high risk canine patients].

The concept of balanced anaesthesia aims at an anaesthetic method for high risk patients by combination of different anaesthetic drugs. The anaesthetics and muscle-relaxants have to work in a way as to potentiate their effects and to reduce the side effects as well as the applied dosage. With this sensible regime the circulation and the metabolic energy should be less burdened. For the introduction of balanced anaesthesia, a combination of benzodiazepines (relaxing and sedative), morphine (analgetic and sedative) and quickly metabolizing hypnotics of the imidazol group (hypnotic and relaxing) is used. A fentanyl-drip-infusion continues and deepens the analgesia. After endotracheal intubation with the help of the carrier-gas nitrous oxide (weakly analgetic) and oxygen (2:1) a low concentration of volatile inhalation anaesthetics (weakly hypnotic) is added. Under artificial respiration low doses of competitive antidepolarizing neuromuscular blockers help to potentiate and reduce drug amounts of other anaesthetics especially of that for inhalation. At the end of balanced anaesthesia an antagonization of benzodiazepines, morphines and competitive neuromuscular blockers is recommended for emergency situations only because of possibly occurring changes of cardiovascular parameters.

Anesthesia↗
PubMed1987

[Meniscus transplantation--animal experiment study].

The possibility of repairing meniscus lesions by transplantation was studied in 30 sheep. Grafting of the meniscus was performed in 15 animals each either with lyophilised homologous menisci that had been sterilised by gamma rays, or with deep frozen homologous menisci. 27 menisci could be evaluated over a period of 48 weeks. Besides the clinical, microscopical and scanning electron microscopical evaluation, the grafts were also examined microangiographically and biomechanically. Both lyophilised and deep-freeze menisci are suitable for transplantation, but the processes of transformation of the grafts are significantly different: Whereas complete transformation takes place in the lyophilised transplant during the study period of 48 weeks, the deep-frozen transplant is accepted and heals without any remarkable transformation process to full function. Although the biomechanical stress tests yielded good stress tolerance for both types of transplants, the deep frozen homologous menisci appear to be more favourable with regard to possible clinical aspects since they do not undergo any transformation.

Animals↗
PubMed1987

Animal experiments on hemostasis with a collagen-fibrin tissue-adhesive sealant in the nephrostomy tract.

After a median laparatomy, nephrostomy was performed on 22 porcine kidneys: puncture, dilatation and introduction of a 26-French operating sheath through the parenchyma into the renal pelvis. At the end of the operation, an 8-French nephrostomy catheter prepared with a collagen-fibrin tissue-adhesive sealant was introduced through the operating sheath and the sheath was afterwards extracted. The hemostasis in the nephrostomy tract was very good in all 22 cases. There were no complications such as wound infection or stone formation during a post-operative period of between one and 95 days. Experimental investigations showed severe bleeding in nontamponade of the nephrostomy tract, in tamponade with an 8-French nephrostomy catheter and in tamponade of the nephrostomy tract with the collagen fleece wrapped around an 8-French nephrostomy catheter but not coated with the fibrin glue.

Animals↗
PubMed1987

[Morphologic examination of the urothelium after irradiation with laser energy].

The energy of a Nd-YAG laser (1,064 nm wave length, 8 ns pulse duration) was used to irradiate the urothelium of the ureter or bladder and kidney parenchyma in pigs. Single pulse energy was 50-120 mJ with a 20-Hz repetition rate. The horizontal laser beam was reflected 90 degrees down by a 100% mirror and with a specially designed apparatus focussed on the surface of the tissue. Laser light from a quartz glass fiber was also focussed directly onto the tissue. Urothelium and kidney parenchyma were irradiated in 7 pigs. Tissue samples were examined histologically and raster electron microscopically 2, 4, 8 and 12 days after irradiation. No macroscopic lesion could be found. Maximum energy caused a small cone of 40 micron depth. No thermic effects or necrosis resulted, so that no harm is to be expected with unintentional irradiation.

Animals↗
PubMed1987

[The clinical administration of the opioid antagonist naloxone in dogs].

The short introduction gives a review on the complex of exogen and endogen opioids and their receptors as well as on their pharmacodynamics, pharmacokinetics and toxicity of naloxone. The clinical efficacy of naloxone as an opioid antagonist is described. Applications of naloxone for the dog are specified: antagonisation of etorphine, morphine, levomethadone and fentanyl, antagonisation of exogen and endogen opioids in puppies and treatment of lactomania in the bitch. The mean effective dose to antagonize morphines is 0.003 mg/kg bodyweight. If persisting analgesia is indicated the dose of naloxone in titrating steps in 0.001 mg/kg bw. To antagonize postpartal hypoxia in puppies 0.02 mg per animal naloxone have to be injected. For treatment of lactomania a dose of 0.01 mg/kg bodyweight twice a day for a couple of days is recommended. The clinical effectivity of naloxone is proved doubtlessly. Compatibility and safety are very high.

Animals↗
PubMed1986

The ingrowth quota of autologous spongiosa from different points of removal--experimental study in sheep. A preliminary report.

The importance of the point of removal for the ingrowth quota of autologous spongiosa was examined in seven sheep. In six sheep spongiosa was taken from five different regions (proximal radius, olecranon, pelvic crest, trochanter major, and proximal tibia) and was transplanted autologously. Defined corticalis defects of the tibia were the chosen sites for the heterotopic implantations. The ingrowth quota were tested by X-ray as well as scintigraphically, histologically, and fluorescent-microscopically; one animal was taken for control. A judgement was made by quantifying scintigraphy and fluorescent-microscopic histometry. Better ingrowth quota were found for spongiosa from the pelvic crest, proximal tibia, and trochanter major as compared to qualitatively clearly worse transplants from radius base and olecranon. The results from the animal experiments prove the clinical experience.

Animals↗