Ultrasonography of the equine neonatal kidney

Ultrasonography is important in the clinical examination of the foal. The ultrasonographic appearance and size of the neonatal kidneys were defined and an imaging protocol established in 6 normal Thoroughbred foals (mean age +/- s.d. 5.0 +/- 3.2 days). Characteristically, in both the heart-shaped right kidney and bean-shaped left kidney, the renal cortex was more echogenic than the medulla. The terminal recesses, renal crest and pelvis were identified, as was the ureter, which contained anechoic urine in its lumen. The renal, interlobar and arcuate vessels were seen. For the right kidney, the ultrasonographic probe was placed at the 14-17th intercostal spaces and paralumbar fossa. For the left kidney, the probe was at the 16th or 17th intercostal spaces and paralumbar fossa. Perirenal structures, including the caudate lobe of the liver, the dorsal extremity of the spleen, the adrenals, the aorta and caudal vena cava were also identified. An understanding of the ultrasonographic appearance of the normal neonatal kidney, accompanied by a routine imaging protocol to ensure that all regions of each kidney are examined, permit a more informed interpretation of renal images in the first few days postpartum.     

Ultrasonography of the equine elbow technique and normal appearance

This study was intended to document normal ultrasonographic appearance of the equine elbow and anatomic landmarks useful in clinical imaging. Both forelimbs of five equine cadavers and both forelimbs of six live adult horses were used (4 Arabian-Barbes, 3 Arabs, 2 Anglo-Arabs, 1 Selle Français, 1 Anglo-Hispano-Arab, three to 18 years old). To facilitate the reading of the scans, a zoning system was developed for some anatomic structures. Ultrasonography was performed with a real-time B-mode semi-portable sector scanner using 7.5 & 5 MHz transducers. On one cadaver limb, MRI was performed on a system at 1.5 Tesla, T1 weighted spin echo, TR of 475 msec, RE of 15 msec, image matrix size 179 × 256 pixels. Ultrasonography images were compared with gross anatomy and with MRI scans to provide the normal ultrasonographic representation of the equine elbow. The lateral collateral ligament, the triceps brachii tendon with its subtendinous bursa, the proximal tendon of the ulnaris lateralis and the articular cartilage of the humeral trochlea were easy to examine ultrasonographically. The medial collateral ligament and the distal biceps brachii tendon required more expertise to assess. Ultrasonographic appearance and course of these structures are described. The 7.5 MHz transducer was best to be used. Ultrasonographic findings correlated well with MRI scans and with gross anatomy in the cadavers' limbs.     

Ultrasonography of the acute abdomen

For many years, ultrasonography has been considered to be one of the most valuable imaging techniques for evaluation of the abdominal cavity and its organs. In most cases, abdominal ultrasonography helps obtain information that leads to a definitive diagnosis. Ultrasonography is also valuable to narrow the list of differential diagnoses obtained with other diagnostic techniques. This article discusses the role of ultrasound for the diagnosis of the most common diseases that can produce clinical signs of acute abdominal pain. Abdominal organs that can be evaluated using ultrasound include the liver, biliary system, pancreas, stomach, small intestine, kidney, urinary bladder, uterus, and prostate. Pathologies of the abdominal cavity and retroperitoneal space can be also diagnosed with ultrasonography. Interventional ultrasound techniques are useful to either assist in getting the definitive diagnosis or to treat certain pathologic conditions.     

Histomorphology of the equine cervix

The cervix provides an effective, morphological barrier between the uterus and the outside world. The aim of this study was to characterize the epithelial morphology and the vascular structures of the equine cervix along the longitudinal and horizontal axis in more detail by light microscopy. For this purpose, cervical tissue specimens that had been removed from five different regions along the caudocranial axis of 10 genitally healthy mares were available. The histological staining was carried out with haematoxylin-eosin, azan according to Heidenhain, periodic acid-Schiff reaction and resorcinfuchsin. An average epithelial cell height of 17.5 +/- 1.7 microm is measured, there being differences in the various areas of the mucosal folds and along the longitudinal axis of the cervix. Three types of cells can be differentiated morphologically. Contrary to the data in the literature, in a large number of cells the free cell membrane shows a clearly discernible border of kinocilia along the total cervical canal. The deep layers of the lamina propria mucosae show pronounced vascularization (46.3 +/- 25.1 vessels/mm2) that mainly consists of veins and venules. Support of the occlusive function of the cervical canal in the form of a cavernous body is assumed to be the function of this vascular plexus.     

Ethmoid hematoma of the equine

Two cases of ethmoid hematoma of the equine are reported. Clinically both horses had intermittent unilateral epistaxis unassociated with exercise. In one horse, diagnosis was based on the use of an endoscope for visualization and for biopsy of a mass associated with the ethmoid turbinates. In the other horse, exploratory trephination of the posterior maxillary sinus was necessary to obtain a diagnostic biopsy specimen. Radiography was helpful in the diagnosis of one case. Surgical removal of the mass was attempted in one case. Histological examination of the biopsies was the single most definitive diagnostic technique in both cases.     

Ultrasonography of the eye and orbit

The eye and orbit are excellent subjects for ultrasonic evaluation. Examination and interpretation are relatively simple procedures. The normal ultrasonic anatomy of the eye and orbit is presented. Some examples of ocular and orbital pathology are discussed also.     

Utilization of stress in the development of an equine model for equine protozoal myeloencephalitis

Neurologic disease in horses caused by Sarcocystis neurona is difficult to diagnose, treat, or prevent, due to the lack of knowledge about the pathogenesis of the disease. This in turn is confounded by the lack of a reliable equine model of equine protozoal myeloencephalitis (EPM). Epidemiologic studies have implicated stress as a risk factor for this disease, thus, the role of transport stress was evaluated for incorporation into an equine model for EPM. Sporocysts from feral opossums were bioassayed in interferon-gamma gene knockout (KO) mice to determine minimum number of viable S. neurona sporocysts in the inoculum. A minimum of 80,000 viable S. neurona sporocysts were fed to each of the nine horses. A total of 12 S. neurona antibody negative horses were divided into four groups (1-4). Three horses (group 1) were fed sporocysts on the day of arrival at the study site, three horses were fed sporocysts 14 days after acclimatization (group 2), three horses were given sporocysts and dexamethasone 14 days after acclimatization (group 3) and three horses were controls (group 4). All horses fed sporocysts in the study developed antibodies to S. neurona in serum and cerebrospinal fluid (CSF) and developed clinical signs of neurologic disease. The most severe clinical signs were in horses in group 1 subjected to transport stress. The least severe neurologic signs were in horses treated with dexamethasone (group 3). Clinical signs improved in four horses from two treatment groups by the time of euthanasia (group 1, day 44; group 3, day 47). Post-mortem examinations, and tissues that were collected for light microscopy, immunohistochemistry, tissue cultures, and bioassay in KO mice, revealed no direct evidence of S. neurona infection. However, there were lesions compatible with S. neurona infection in horses. The results of this investigation suggest that stress can play a role in the pathogenesis of EPM. There is also evidence to suggest that horses in nature may clear the organism routinely, which may explain the relatively high number of normal horses with CSF antibodies to S. neurona compared to the prevalence of EPM.