Histological changes following Nd YAG laser photocoagulation of canine gastric mucosa

Tissue changes produced in the dog stomach by exposure to a Nd YAG laser varied from mild mucosal oedema to cell vaporisation. Intermediate degrees of damage caused a marked inflammatory response leading to extensive fibrosis in the submucosa and muscularis propria. The true extent of tissue damage was not apparent immediately, and treated mucosa that initially appeared intact sometimes sloughed several days later to leave an ulcer. The extent of damage and the rate of healing depended on the amount of laser energy used. With pulses at optimum laser power (75 w) and exposure time (0.4 sec), however, haemostasis was achieved in induced ulcers with total energy concentrations that did not produce full thickness tissue damage nor alter the healing rate from that observed in untreated ulcers. Thermal contraction was the primary haemostatic mechanism, thrombosis only occurring as a secondary effect.

Nature and extent of histological changes induced by argon laser photocoagulation in canine gastric mucosa

The tissue changes in canine gastric mucosa caused by exposure to an argon laser beam vary from mild mucosal oedema to complete cell destruction. Intermediate degrees of damage cause an inflammatory cell response with the formation of granulation tissue, particularly in the submucosa. The rate of healing is similar to that after other forms of injury to the gastric mucosa. Cell destruction at the surface of the mucosa starts with energies greater than 8 Joules on any one spot, and occurs at greater depths as the energy is increased but, unless cells are actually destroyed, the extent of histological damage is limited to a zone 1 mm lateral to, or below, the area exposed to the laser beam. Haemostasis is achieved by thermal contraction of bleeding vessels and of the surrounding tissue, thrombosis only occurring as a secondary effect.

An outbreak of type C botulism in captive monkeys

In an outbreak of type C botulism in a group of captive primates, six squirrel monkeys, six white throated capuchin monkeys and two weeper capuchin monkeys succumbed rapidly and died. Clostridium botulinum type C toxin was detected in the remains of the chopped chicken feed and in nine of 11 blood samples and one of three stomach contents samples from the affected animals.

NdYAG laser photocoagulation in the dog stomach

Considerable discussion still centres around the relative merits of the Argon and Neodymium Yttrium Aluminum Garnet (NdYAG) lasers for the endoscopic treatment of gastrointestinal haemorrhage, although both are undoubtedly effect. We have carried out experiments to elucidate which factors determine the safety and efficacy of NdYAG laser photocoagulation. Histological studies on normal gastric mucosa showed that the depth of tissue damage depended mainly on the total incident laser energy, whereas the effectiveness of photocoagulation of induced gastric ulcers in heparinised animals depended on the laser power and the exposure time used. Optimum haemostasis with minimum tissue damage was obtained using pulses of 300 to 500 ms duration with energies of 25 to 40 J. We consider these parameters safe and effective for use in pilot clinical studies.

Ligation and sclerosis of the epididymis in the bull

In an attempt to induce permanent aspermia the caudae epididymes of 17 bulls were subjected to ligation or injection with ethanolamine or chlorhexidine in dimethyl sulphoxide. Nylon and polyglycolic acid ligatures had little or no effect on the sperm counts although these materials were used in only three bulls. Steel ligation induced aspermia of several weeks' duration in four of six bulls. Although the effect in at least three of these animals might have been permanent, the trial was discontinued because the other two bulls, treated identically, showed little response. Ethanolamine injected into the epididymis also had little or no effect on the ejaculate. By contrast the chlorhexidine preparation produced an almost immediate aspermia sustained until the bulls were slaughtered a year later.

Argon laser photocoagulation in the dog stomach

Laser photocoagulation is one of a number of methods currently under investigation for the endoscopic treatment of gastrointestinal haemorrhage. The Argon ion and Neodymium Yttrium Aluminium Garnet (Nd YAG) lasers are theoretically suitable as the beam from each may be transmitted via a flexible fibre. Argon laser photocoagulation has been shown to be effective and we have elucidated which factors determine its safety and efficacy. Studies on normal canine gastric mucosa showed that the depth of tissue damage depended chiefly on the total incident laser energy on any one spot, and that below 50 J the risk of perforation was extremely low. The energy density was much less important. The haemostatic effect depended more on the laser power. In artificial bleeding gastric ulcers in heparinised dogs the most effective level was 7--9 W, at which 22 out of 23 ulcers (96%) stopped bleeding completely, compared with one out of 12 controls. Photocoagulation was achieved in these cases with energies well within the safe limits. The procedure was effective endoscopically, and these results justify early clinical studies in man.

Impaired parathyroid response to induced hypocalcemia in thalassemia major

Ethylene diamine tetra-acetic acid-induced hypocalcemia was used as provocative test of parathyroid reserve in eight normocalcemic patients with thalassemia major (age 8 to 26 years) and five young adult control subjects (age 22 to 35). In response to an intravenous infusion of disodium EDTA (50 mg/kg), serum immunoreactive parathyroid hormone rose by 1.97 +/- 1.93 (SD) microliterEq/ml in the patients, controls showing a rise of 10.6 +/- 3.6 microliterEq/ml (t = 5.46, P less than 0.001). There was no relationship between parathyroid response and total iron burden as measured by serum ferritin- or desferrioxamine-induced urinary iron excretion. Impairment of parathyroid reserve is common in transfused patients with thalassemia major and may serve as a marker of significant iron overload.

Megaloesophagus and associated gastric heterotopia in the cat

Two young adult male Siamese cats had heterotopic gastric mucosa in the dilated and inflamed oesophagi. Normally differentiated gastric mucosal glands were present and there was severe ulceration in one cat. It is uncertain whether the gastric heterotopia was a reparative change after oesophagitis or whether it represented a coincidental anatomical anomaly.

Priapism after sedation, neuroleptanalgesia and anaesthesia in the horse

The paper reports 6 cases of priapism with subsequent protrusion and paresis after neuroleptanalgesia and anaesthesia in horses. Five were ultimately treated by amputation of the penis but the sixth horse is responding satisfactorily to conservative treatment at the time of writing. Causative factors, preventive measures and possible methods of treatment are discussed.

Epidemiology of Salmonella infection in calves: the source of calfhood infection by Salmonella dublin

Investigation of the source of neonatal Salmonella dublin infection of calves was undertaken by carrying out caesarean section of cows with a history of excretion of S dublin following either S dublin enteritis or S dublin abortion. No evidence of transplacental infection was detected but six of 10 animals showed evidence of excretion of the organism in the faeces, vaginal discharge or milk in the period immediately following parturition. The strong probability of early infection as a result of contamination of the environment is therefore suggested.

Alpha-adrenergic blockers in prostatism

Thirty patients awaiting prostatectomy with no history of cardiovascular disease were selected for a trial of alpha-adrenergic blocking agents. Twenty-seven patients completed the trial, 19 of them with unpleasant side effects. Eighteen of them found their symptoms were improved and 10 showed urodynamic improvement.

Intestinal obstruction in cattle

Based on a series of 100 cases, the paper reviews the causes, diagnosis and treatment of apparent bowel obstruction in cattle with particular emphasis on non-obstructive tympanitic disorders of the intestine.

Acute respiratory distress in the dog associated with paraquat poisoning

An acute respiratory distress syndrome in 10 adult dogs was usually preceded by vomiting, anorexia and lethargy followed, after a short interval, by dyspnoea. The dyspnoea became increasingly severe, despite oxygen therapy, and cyanotic respiratory failure ensued. All 10 dogs died or were killed after illnesses lasting between one and eight days. Necropsies revealed pulmonary congestion, oedema, collapse and haemorrhage with loss of alveolar epithelial cells. Early alveolar fibrosis was also found. Paraquat was identified in post mortem samples from four of the 10 dogs.

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.