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Biomedical subjects

A Waterman

Publications and source records attributed to A Waterman.

At least 19 recordsLinked to original sources

Chronic intrathecal catheterization in the sheep.

This paper describes a relatively simple and noninvasive method for the chronic implantation of intrathecal catheters in the sheep. The technique has been carried out on 17 occasions in nine sheep, with 60% of attempted catheterizations producing a correctly positioned, functional catheter. The placement and integrity of the catheters were confirmed by radiography using a contrast medium. Correctly placed catheters have been maintained for up to 16 months without problems.

Animals

The influence of chronic pain on the analgesic effects of the alpha 2-adrenoceptor agonist, xylazine, in sheep.

A comparison of the analgesic potency of the alpha 2-adrenoceptor agonist, xylazine, in control healthy sheep and sheep suffering chronic pain from footrot, indicated that the analgesic effectiveness of xylazine was significantly reduced in the animals experiencing chronic pain. This was measured by recording the threshold to a mechanically applied pressure stimulus. Furthermore, when the condition was apparently resolved, by conventional treatment over a period of 2 to 3 weeks, the decreased analgesic effectiveness of the alpha 2-agonist was still apparent although the animals were clinically cured of the footrot.

Analgesia

The management of bovine fractures: a review of 59 cases.

Current trends in bovine fracture repair are reviewed with reference to 59 cases. Thirty-one cases were managed surgically, 14 by external fixation, and six by stall confinement. Eight animals were slaughtered without treatment being attempted. A successful outcome was achieved in 90 per cent of the surgically treated cases, compared with 57 per cent for those treated by external fixation methods.

Animals

Analgesic effects of intrathecally-applied alpha 2-adrenoceptor agonists in conscious, unrestrained sheep.

Intrathecal injections of small volumes of the alpha 2-adrenoceptor agonists, xylazine and clonidine, into the cervical region of the spinal cord of conscious unrestrained sheep produced a dose-dependent analgesia of the forelimbs as measured using a mechanical pressure device. Intravenous injection of the alpha 2-adrenoceptor antagonist, idazoxan completely abolished the analgesic effects of the intrathecally applied alpha 2-adrenoceptor agonists. Subsequent studies using [3H] clonidine injected at a similar dose and volume via the intrathecal catheters, indicated that the volume of drug used, 100 microliter, gave a localisation of the drug limited to about five vertebral segments around the catheter tip.

Adrenergic alpha-Agonists

Techniques for comparison of thermal and mechanical nociceptive stimuli in the sheep.

The assessment of analgesia in conscious unrestrained farm animals presents particular problems. In order to provide a reliable nociceptive stimulus, two devices have been constructed, one that provides a threshold reading for a ramped thermal stimulus of the pinna of the ear and another that measures a threshold reading for a pressure stimulus to the foreleg. Both devices allow the rapid termination of the stimulus once a reaction has occurred and allow repeated readings without causing tissue damage. Examples of the analgesic action of alpha 2-adrenoceptor agonists and opioids measured by using the two pieces of apparatus are shown.

Animals

Antinociceptive actions of intravenous alpha 2-adrenoceptor agonists in sheep.

The antinociceptive activity of the intravenously administered alpha 2-adrenoceptor agonists, clonidine and xylazine, was measured in sheep using thermal and mechanical pressure threshold detection systems. Both drugs demonstrated clear antinociceptive activity for both forms of threshold stimuli and clonidine at 6 micrograms/kg i.v. was more potent and longer lasting than xylazine at 50 micrograms/kg i.v. The antinociceptive effects were reversed by idazoxan (0.1 mg/kg i.v.), but were not affected by naloxone at 0.2 mg/kg i.v. indicating that these effects were mediated by alpha 2-adrenoceptors.

Adrenergic alpha-Agonists

Threads of cultural nutrition: arts and humanities.

Cultural nutrition encompasses a wide sweep of food-related themes within three major categories: arts and humanities, social sciences, and biological-natural sciences. The paper, first of three, considers the arts and humanities. Topics include food and diet expressed through art, film, music, and dance. The essay then examines food and diet in representative works of literature, both ancient and modern. The place of food and diet within folklore, mythology, and religion is treated, with consideration of symbolic roles played by food throughout the human life cycle, especially with birth and infancy, coming-of-age, marriage, and death. Religion, a major theme in cultural nutrition, is explored and the food-dietary patterns of Jews, Christians, Moslems, Hindus, and Shintos are treated. Ethics and philosophy are examined as both relate to programs of international food relief and vegetarianism. The essay concludes with a review of work by historians, especially themes of famine and approaches taken to refeed populations during combat and hostilities.

Culture

The effects of alpha 2 adrenoceptor agonists on airway pressure in anaesthetized sheep.

Xylazine and clonidine, given intravenously, cause an increase in airway pressure in the anaesthetized, ventilated sheep. This increase was dose dependent and was not mediated by histamine, nor was it blocked by the alpha 1-adrenoceptor antagonist prazosin. However, the increase was abolished by the alpha 2-adrenoceptor antagonist, idazoxan. When the alpha 2-adrenoceptor agonists were administered into the cerebrospinal fluid by injection into the cisterna magna there was no increase in airway pressure, although a similar dose given peripherally still produced an effect. These findings would indicate that the increase in airway pressure seen in these sheep, following administration of xylazine and clonidine, was mediated by peripherally located alpha 2-adrenoceptors.

Adrenergic alpha-Agonists

Some physiological effects of ketamine in sheep.

The effects of intravenous injections of ketamine in sheep on the cardiovascular and respiratory systems are compared with the effects of intracerebroventricular injections of the same drug and also with the effects of intravenous barbiturate and steriod anaesthetics. Intravenously administered ketamine caused an initial fall in arterial blood pressure the extent of which was dose dependent. This depression was short lived and was occasionally followed by a mild pressor phase. Intracerebroventricular injection of the drug provoked only a mild transient rise in mean arterial blood pressure. The intravenous injection of ketamine gave a brief period of respiratory depression which was mirrored in the PaO2 and PaCO2 levels followed by a period of respiratory stimulation with elevated PaO2 levels. The comparison of the three injection anaesthetics showed that the blood gas tensions with ketamine showed there was a brief period of respiratory depression similar to that seen with the steroid anaesthetic but that the barbiturate caused a much longer depression similar to that seen with the steroid anaesthetic but that the barbiturate caused a much longer depression. The blood gas tensions following the steroid anaesthetic soon returned to normal while the tensions following ketamine indicated an elevated PaO2 after the initial depression. The blood gas tensions following intracerebroventricular injection of ketamine were difficult to evaluate due to the variable period of apnoea which followed the injection.

Alfaxalone Alfadolone Mixture

Rupture of the diaphragm in the horse.

Four cases of fatal diaphragmatic rupture in the horse are described. In 2 cases there was no history of injury but the other 2 animals had sustained recent thoracic trauma. Three of the horses had signs of colic and bowel obstruction complicated, in 2 cases, by respiratory embarrassment; the fourth died rapidly, presumably of shock. Previously published cases are reviewed and the causes, clinical effects, diagnosis and treatment of the disorder are discussed.

Animals

A review of the diagnosis and treatment of fluid and electrolyte disorders in the horse.

Disturbances of fluid and electrolyte balance may occur in the horse as a consequence of many disease processes. Disorders may be classified into 3 main categories, primary water loss, mixed water and electrolyte depletion and acid base disturbances. This paper reviews the changes which occur with each type of disorder and discusses methods of diagnosis and assessment of such imbalances. The principles of treatment are described and the management of fluid replacement therapy in 3 of the disorders, mainly acute intestinal obstruction, inability to drink and diarrohea is discussed.

Animals

Accidental hypothermia during anaesthesia in dogs and cats.

The rectal temperature of 15 cats and 18 dogs was recoded during anaesthesia and surgery. There was a mean decrease of 3-4 degrees C in animals weighing less than 10kg and of 1-5 degrees C in animals weighing on average 30-2kg. In four dogs which were protected from accidental hypothermia by the use of a circulating warm water blanket, the mean decrease in rectal temperature was 0-5 degrees C.

Alfaxalone Alfadolone Mixture