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Biomedical subjects

J Arnbjerg

Publications and source records attributed to J Arnbjerg.

At least 37 records · Page 2Linked to original sources

Increased glucose content in the aqueous humour caused by the use of xylazine.

Xylazine has a strong hyperglycaemic effect due to its blocking of the pancreatic insulin release via stimulation of parasympathetic (alpha 2-adrenergic) receptors. Therefore xylazine also increases the content of glucose in the aqueous humour considerably. This increase might be regarded as the inducing factor of the diabetogenic cataractous changes seen in animals with a low tolerance to high glucose levels in the aqueous humour. Xylazine must still be regarded as one of the better combinations with ketamine, because of its reproducible and stable anaesthetic effect in this combination in cats. However, the use of xylazine should be carefully considered, especially in eye surgery, until further controlled information is available.

Animals↗

Myocardial preservation during anoxic arrest. Chemical cardioplegia.

Two types of cardioplegic solution--the potassium arrest and the Bretschneider solution, both at 4 degrees C--were compared with regard to protective effect against ischemic damage during 60 min of anoxic cardiac arrest in the dog heart. Both solutions provided equally good protection, which was superior to that given by hypothermia alone.

Animals↗

Myocardial preservation during anoxic arrest. Premedication with propranolol, verapamil or methylprednisolone.

Anoxic cardiac arrest was studied for one hour in five groups of dogs. Groups I-III were given methylprednisolone (30 mg/kg b.w.) before aortic cross-clamping. Normothermia was used with electrically induced ventricular fibrillation in group I, and without such fibrillation in group II, while group III was studied in local hypothermia. Propranolol (10 micrograms/kg) was given to group IV and verapamil (0.2 mg/kg) to group V before the anoxic arrest in local hypothermia. Judged from the ability of the heart to take over the circulation after anoxic arrest, local cooling preceded by propranolol or verapamil gave working performance comparable with the pre-arrest values. In the cooled, steroid-pretreated hearts the work capacity was depressed to the same degree as in locally cooled hearts without steroid premedication. Methylprednisolone prevented ischemic contracture during normothermic arrest with induced fibrillation, but not in the absence of such fibrillation. As adjuvant to local cooling, pretreatment with metabolism-reducing drugs is favorable for cardiac performance after arrest. Steroid premedication should be considered when normothermic arrest with electrically induced ventricular fibrillation is planned.

Animals↗

Myocardial preservation during anoxic arrest. Experimental model ventricular fibrillation.

An experimental model with anaesthetized healthy mongrel dogs on extracorporeal circulation is described. Anaesthesia and cardiopulmonary bypass are the same as used in clinical practice. Various methods of myocardial preservation were investigated and their protective effect was judged by cardiac performance after termination of 60 min of anoxic arrest. In this study, the first part of an experimental series, electrically-induced fibrillation during 60 min of normothermic and local hypothermic anoxic arrest was investigated. In group I, the hearts were fibrillated immediately after cross-clamping. In group II, which served as controls, the hearts were allowed to fibrillate spontaneously after aortic cross-clamping. All the hearts in group I went into an ischaemic contracture, whereas those in group II showed a 50% recovery, but with a strongly reduced cardiac performance after termination of anoxic arrest and cardiopulmonary bypass. Measurements of myocardial surface pH demonstrated a rapidly developed acidosis during the period of anoxic arrest. The most impressive finding by light microscopy was pronounced myocardial oedema. External cooling by 4 degrees C glucose 5.5% continuously flushed into the pericardial sac in combination with electrically-induced fibrillation proved to be ineffective as a protective method. None of the eight dogs in this group survived. External cooling combined with intraventricular injection of 4 degrees C glucose 5.5% seemed to protect the hearts against ischaemic damage, insofar that all six hearts in this group were able to take over the circulation after declamping. The working capacity was, however, impaired and a relatively long period of mechanical support and stimulation with inotropic drugs was necessary.

Animals↗

Poisoning in animals due to oral application of iron. With description of a case in a horse.

Peroral application of iron salts in various types of anemia was previously considered atoxic. The increased use of iron has, however, led to an increasing number of poisoning in children, taking iron tablets for candy. There have only been reported a few number of spontaneous intoxications in animals, but experimentally it has been possible to produce fatal intoxications in various kinds of animal species. The clinical findings are quite similar in the various animals, starting with vomiting, bloody diarrhoea and metabolic acidosis. If the intoxication is severe, shock and coma may develop, and death occurs quite soon. The histological findings are also similar in the various animals, varying from erosions of the tops of the villi to necrosis of the mucosal membrane of the jejunum. Degenerative changes in the liver as well as in the kidney are seen in several cases. The mentioned case was a horse given about 475 g ferro fumarate over a period of 5 days. The horse developed the classic clinical picture and death occurred on day 7. The diagnosis was confirmed by very high levels of iron in the liver, kidney and serum. The blood values of the enzymes ASAT and gamma GT were extremely high as a sign of a severe damage of the liver.

Administration, Oral↗

[Hypocalcemia in the horse. A case report].

With reference to previous reports on hypocalcemia in horses special attention is given to the principal symptoms such as anxiety, increased muscular tension, esp. of the musculature of the extremities, in severe cases leading to ataxia, and to a pulse-synchronized respiration (Synchronous Diaphragmatic Flutter). The time of appearance of the symptoms are much more variable than it is the case for hypocalcemic agalactia in cows. Furthermore the condition has been reported in foals as well as in geldings. Thus the triggering factor seems to be somewhat different from that of agalactia. Hypocalcemic horses also develop decreased manganese blood-level. Treatment with Ca-borogluconat in the horse can be as efficient as is the case in agalactia in the cows, but quite often it is necessary to repeat the treatment. This is illustrated by the fact that the relatively high dose (17 mg Ca/kg) administered to the present patient only increased the Calcium blood level to somewhat below normal. The triggering condition, estrus, weaning of the foal, stress, hard (sweat-provoking) work etc., in many cases perhaps a kind of mental stress, must be adequately treated. An all-round and sufficient feed ration in accordance with the working load and eventually with milk production may prove to be much more essential than realized so far for the prevention of hypocalcemia in horses.

Animals↗

[Clinical use of ketamine-xylazine for anaesthesia in the cat (author's transl)].

Based on experiences from anaesthesia of approximately 7000 cats in a four year period the effects of a combination of 20--25 mg/kg Ketamine and 0.5 mg/kg Xylazine given i/m are described. In the present study the Xylazine has been applied in considerably lower doses, compared with previous reports on these drugs, and this change has reduced the unwanted side effects, without at the same time reducing the effect on the muscular tension and the psychical disturbances induced by the Ketamine. Ketamine and Xylazine were given in one injection after being taken in the named sequence and mixed in the syringe. Indication for anaesthetizing the cats were, besides routine surgery in the out-patient clinic, operations of weakened animals for pyometra, foreign bodies, intestinal invaginations with and without resection, removal of abdominal tumors and urolithiasis. Animals with impared liver function were not anaesthetized with these drugs due to the important role of liver metabolism in their excretion. In spite of the fact that the corneal and laryngeal reflexes normally persist, the combination of the two drugs allowed surgery in these organs after application of local anaesthetics as an extra precaution. Premedication with atropine has not been used routinely, and still only very few cases of increased salivation or vomiting have been observed. Aspiration has not been a complication and in the whole material, only 3 deaths have occurred, none of them with a specific post mortem finding besides shock. In these 3 cases the patient died later than 45 minutes after the injection and after ended surgery. Side effects ascribed to phenomena of interaction have not been observed. One cat was anaesthetized a number of times during pregnancy without any effect on the cat or its kittens. It is concluded, that the Ketamine/Xylazine combination, when mixed as prescribed gives a very safe and pleasant narcosis, and that side effects are minimized, if the corneas are moistened with an ophthalmic ointment and the patient is allowed to recover in dark and quiet surroundings.

Anesthesia, General↗

Clinical manifestations of overdose of ketamine-xylazine in the cat.

10 cats were anesthetized with high doses of Ketamine/Xylazine combination (50 mg/kg and 6 mg per cat respectively). 10 other cats were given Ketamine alone (100 mg/kg). The drugs were given i/m. Heart rate and respiratory rate were measured with regular intervals for 3 hours and certain reflexes were checked in the same period. Blood parameters (pH, pO2, pCO2) from arterial blood, were studied 10--15 min. after application. The values measured after application of these high doses never reached critical levels and no clinical signs of cyanosis were observed. Physostigmine has been reported to have an antagonistic effect on Ketamine in humans, but this could not be demonstrated in cats. The increase of dose levels did not improve or lengthen the anaesthetic effect of the drugs, but the period of recovery was highly extended. There were no clinical signs of acute toxicity and it is concluded that even severe misjudgements of the bodyweight should not lead to fatal results.

Anesthesia, General↗

Spontaneous fracture of the navicular bone in the horse.

After a short review of previous literature about fractures of the navicular bone in horses, the symptoms and the pathological-anatomical changes of the condition are described. The most important clinical symptom is acute severe lameness without significant swellings, but with pronounced pain reaction to rotation of the coffin joint. After rest the lameness is reduced considerably, but without treatment it can persist for several years. Adherences between the deep flexor tendon and the site of the fracture and eventual damage to the coffin joint are considered to be the cause of the persisting lameness. Three case reports are given where the horses were shoed with full bar shoes with clips and high calks, and were given two months rest in a box. After that the rehabilitation was started with increasing load on the leg in question in spite of some initial lameness. The three horses all regained their full working capacity after ca. 6 months' treatment. There is no formation of callus at the site of the fracture, but only a firm formation of fibrous tissue which does not bother the horse unless the fragments are too much dislocated giving rise to a greater destruction of the coffin joint. Radiographically the fracture line persists for the rest of the horse's life.

Animals↗

Acid-base status of canine blood during storage.

The changes in pH, pCO2, pO2, based excess, standard bicarbonate and lactic acid during storage of canine blood 24 hours at different temperatures were measured (table I a, b) and illustrated (figs. 1 and 2). A correction table (table V) for determination of the initial acid-base data is constructed based upon regression equations (table IV) of the in vitro changes during storage of the blood. The changes in the acid-base values of canine blood differ from that of bovine and human blood (tables II and III).

Acid-Base Equilibrium↗