DENTAL RADIOGRAPHY IN THE DOG WITH A CONVENTIONAL X-RAY DEVICE

This study describes a method of using a conventional x-ray device and film-positioning system for dental radiography in dogs. This system is economical, safe and results in high quality dental radiographs.     

COMPARISON OF TRANSCOLONIC 123I-IODOAMPHETAMINE AND PORTAL VEIN INJECTION OF 99mTc-MACROAGGREGATED ALBUMIN SHUNT FRACTION CALCU-LATIONS IN EXPERIMENTAL DOGS WITH ACQUIRED POR-TOSYSTEMIC SHUNTS

Shunt fraction was determined using transcolonic ¹²³I-iodoamphetamine (IMP) and portal vein injection of ^99mTc-macroaggregated albumin (MAA) in a group of eight dogs with chronic cirrhosis and acquired portosystemic shunts subsequent to total common bile duct ligation. Hepatic parenchymal damage was confirmed by alterations in liver function tests and liver histology. Seven of the eight dogs developed portal hypertension and had angiographic evidence of hepatofugal portal blood flow with multiple peripheral portosystemic anastomoses. Shunt fractions determined in the seven dogs with shunts varied from 39 to 100 using IMP and 45 to 93 using MAA. The remaining dog had normal portal pressure, a normal portal angiogram, and normal IMP and MAA scintigraphic studies. There was an excellent correlation between the two methods of shunt fraction calculation (R²= 0.98) and the line of regression was not significantly different from unity (IMP = 1.09 × MAA - 0.03).     

LOW FIELD MAGNETIC RESONANCE IMAGING OF THE CANINE CENTRAL NERVOUS SYSTEM

Magnetic resonance (MR) imaging is a relatively new method of medical imaging. MR studies on the normal canine central nervous system were performed using a low field MR scanner. The regions of interest were the head, neck, and lumbar region. The MR findings in two patients with brain atrophy and cervical neck disc protrusion were also evaluated. Based on our findings it appears that low-field scanners will be satisfactory for use in veterinary diagnostic imaging.     

Multiple, distinct forms of bovine and human protein kinase C suggest diversity in cellular signaling pathways

A new family of protein kinase C-related genes has been identified in bovine, human, and rat genomes. The alpha-, beta-, and gamma-type protein kinase sequences are highly homologous, include a kinase domain, and potential calcium-binding sites, and they contain interspersed variable regions. The corresponding genes are located on distinct human chromosomes; the possibility of even greater genetic complexity of this gene family is suggested by Northern and Southern hybridization analyses.     

The effects of maternal plasma dobutamine levels on fetal oxygenation in anaesthetized sheep

Objective To measure the effects of dobutamine infusion on fetal oxygenation during isoflurane anaesthesia in pregnant ewes. Study design Prospective randomized experimental study. Animals Seven clinically normal adult pregnant Rambouillet‐Dorset cross ewes with fetuses of 117–122 days gestational age. Methods The ewes were anaesthetized with ketamine (2 mg kg^?1) IM, and isoflurane (F_E′ISO 2.0%) in oxygen. After instrumentation and stabilization, dobutamine was infused at 4 µg kg^?1minute^?1 for 60 minutes and 10 µg kg^?1minute^?1 for 60 minutes in random order, separated by a 20‐minute washout period. Catheters were placed in the maternal and fetal carotid arteries; these were used for continuous blood pressure measurement and intermittent blood sampling. Results Maternal mean systemic carotid arterial pressure was 60 mm Hg prior to dobutamine infusion. After 5 minutes of dobutamine infusion, fetal oxygen saturation increased (p < 0.05) from 0.62 (0.17–0.71, minimum–maximum) to 0.72 (0.28–0.78) at a dose of 4 µg kg^?1minute^?1 and to 0.70 (0.20–0.73) at a dose of 10 µg kg^?1minute^?1. These increases were maintained during the infusion and were not significantly different between doses. Maternal oxygen saturation remained constant at 1.0 before and during all infusions. Although maternal heart rate and blood pressure increased (p < 0.05) by 90% and 25%, respectively, with dobutamine, this stimulant effect was not evident in the corresponding fetal variables. Maternal haemoglobin concentration increased 30% (p < 0.05) with each infusion. Conclusions Dobutamine at 4 µg kg^?1minute^?1 increases fetal oxygenation that is not improved by a dose of 10 µg kg^?1minute^?1. This increase is largely due to an increase in maternal haemoglobin concentration that, in turn, increases oxygen delivery to the placenta. Clinical relevance The use of dobutamine to treat hypotension in pregnant sheep during isoflurane anaesthesia improves fetal oxygenation. This may be true in other species.     

Pulsed delivery of nitric oxide counteracts hypoxaemia in the anaesthetized horse

Objective To study the effect of the pulsed delivery of nitric oxide (NO) on pulmonary gas exchange in the anaesthetized horses. Design Prospective, controlled randomized. Animals Five healthy Standardbred trotters, three geldings and two mares. Methods The horses were anaesthetized with thiopentone and isoflurane and positioned in dorsal recumbency. Nitric oxide was added as a pulse to the inspired gas during the first half of each inspiration. In three horses the effect of NO on the ventilation–perfusion distribution was also investigated using the multiple inert gas elimination technique. Data were analysed with repeated measures ANOVA. Results During spontaneous breathing, arterial oxygen tension (PaO₂) increased with NO inhalation, from 14 ± 2 to 29 ± 3 kPa (105 ± 15 to 218 ± 23 mm Hg) (p < 0.001). Arterial oxygen tension also increased, from 17 ± 3 to 31 ± 5 kPa (128 ± 23 to 233 ± 38 mm Hg) (p < 0.05) during intermittent positive pressure ventilation. The increase in PaO₂ was mainly due to a reduced right to left vascular shunt, but ventilation and perfusion matching also improved. The beneficial effect of NO inhalation was lost within 5 minutes of its discontinuation. Conclusion Delivery of NO as a pulse during inspiration is an effective method for counteracting impaired gas exchange caused by anaesthesia in horses. Pulsation has to be continuous because of the transience of NO's therapeutic effect. Clinical relevance Horses with impaired pulmonary gas exchange during anaesthesia can be treated with pulsed NO inhalation.