Biomedical subjects
D J Simpson
Publications and source records attributed to D J Simpson.
An outbreak of contagious equine metritis in 1977 and its effect the following season.
An outbreak of contagious equine metritis occurred in Newmarket in 1977. This survey records the effect on fertility of 20 of the stallions which were infected. Swabbing of mares since then has detected 37 carrier mares harbouring the organism, most frequently in the clitoral area. This swabbing programme reduced the incidence of new cases in 1978 to 3 mares and 1 stallion.
The experimental infection of ponies with contagious equine metritis.
Four pony mares were readily infected with the organism of contagious equine metritis by intracervical inoculation and one by coitus with an infected stallion. Infected mares developed an acute endometritis with local destruction of the endometrial epithelium. In 2 experimentally infected mares, infection appeared to have been spontaneously eliminated from the genital tract within 3 to 4 weeks. A third mare however remained persistently infected in the clitoral fossa over a long period and was a symptomless carrier. Four pony stallions were readily infected in the urethral fossa and the organism survived for varying periods without giving rise to any signs of infection. From 2 of these animals it appeared eventually to have been eliminated spontaneously. An experimentally infected stallion transmitted infection to a healthy mare by coitus. Bacteriological examination of infected pony stallions may occassionally give false negative results and fail to reveal the organism in the external genitalia. Repeated bacteriological examinations need to be undertaken before it can be concluded that a stallion is free of infection.
Swabbing for contagious metritis tests.
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Plastoglobules of leaf chloroplasts of two cultivars of Capsicum annuum.
The chloroplasts of the leaves of Capsicum annuum cv. Purple Leaf Cherry are characterized by the presence of large electron translucent plastoglobules which comprise a considerable proportion of the plastid volume. The leaf chloroplasts of Purple Leaf Yellow cultivar contain, in addition, large starch granules which are frequently in intimate association with these plastoglobules. There appears to be a controlled expulsion of plastoglobules into the vacuole by the non-degenerating chloroplasts of both cultivars, although the function of this secretion is not known. The chloroplasts of older leaves of Purple Leaf Yellow also contain plastoglobules with a nonhomogenous fine structure. Some have granular segments, membrane-like bands, or myelin-like bands, the latter suggesting the presence of glyco- and/or phospholipids in such plastoglobules.
Intestinal surgery in the foal.
Intestinal surgery in the foal is seldom necessary but some conditions in which it is essential are well recognized. The foal is a good surgical subject but success depends mainly on operating promptly before irreversible degenerative changes take place. Exploratory laparatomy is recommended whenever mechanical obstruction is suspected. Indications fall broadly into two main categories: 1. Cases arising from congenital defects. These form a miscellaneous group and present considerable difficulties in diagnosis and effective treatment. 2. Cases related to acute onset of obstruction, mainly due to volvulus or torsion. By far the most important condition in this category is volvulus of the ileum close to the ileocaecal valve. Aetiological factors are discussed, and the value of resection of affected small intestine and creation of a new jejuno-caecal opening is indicated. It is suggested that with improvement of such techniques it will be possible to save a higher proportion of foals suffering from mechanical intestinal obstruction.
Horse strongyles' tolerance to anthelmintics.
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Further studies on the use of synthetic prostaglandin analogues for inducing luteolysis in mares.
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An automatic gate selector device for cattle feeding.
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Intraoperative hemorrhage during patent ductus arteriosus ligation in dogs.
OBJECTIVE: To determine the prevalence of intraoperative hemorrhage in a consecutive series of dogs undergoing patent ductus arteriosus (PDA) ligation at a veterinary teaching hospital, and to describe strategies to reduce the risk of ductus perforation and deal with hemorrhage when it occurs. STUDY DESIGN: Retrospective clinical study. ANIMALS: Sixty-four dogs. METHODS: The records of all dogs undergoing PDA ligation at the University Veterinary Center, Sydney between May 1989 and February 1998 were reviewed and the prevalence and nature of complications identified. RESULTS: Serious hemorrhage occurred in 4 of 64 dogs (6.25%) that underwent PDA ligation. In all cases, hemorrhage resulted from perforation of the craniomedial aspect of the ductus while attempting to expose the tips of the dissecting forceps. Hemorrhage was controlled in 3 dogs by clamping the main pulmonary artery, digital compression of the descending aorta, and completion of ductus ligation during an approximately 5-minute period of circulatory arrest. The remaining dog exsanguinated during an unsuccessful attempt to locate, clamp, and ligate the bleeding point. The mortality rate for PDA ligation was I of 64 dogs (1.6 %). CONCLUSIONS: The technique described in this report permits simple ligation of a range of different ductus morphologies in dogs of varying breeds, weights, and ages. In the event of serious hemorrhage, prompt ventricular outflow occlusion and ductus ligation followed by rapid whole blood transfusion is life saving in most cases.