Description and validation of a magnetic resonance imaging-guided stereotactic brain biopsy device in the dog.

A stereotactic brain biopsy system that is magnetic resonance (MR) imaging-guided has not been validated in dogs. Our purpose was to determine the mean needle placement error in the caudate nucleus, thalamus, and midbrain of a canine cadaver brain using the modified Brainsight stereotactic system. Relocatable reference markers (fiducial markers) were attached to the cadaver head using a dental bite block. A T1-weighted gradient echo three-dimensional (3D) sequence was acquired using set parameters. Fiducial markers were used to register the head to the acquired MR images in reference to a 3D position sensor. This allowed the planning of trajectory path to brain targets in real time. Coordinates (X, Y, Z) were established for each target and 0.5 microl of diluted gadolinium was injected at each target using a 26-gauge needle to create a lesion. The center of the gadolinium deposition was identified on the postoperative MR images and coordinates (X', Y', Z') were established. The precision of this system in bringing the needle to target (needle placement error) was calculated. Seventeen sites were targeted in the brain. The mean needle placement error for all target sites was 1.79 +/- 0.87 mm. The upper bound of error for this stereotactic system was 3.31 mm. There was no statistically significant relationship between needle placement error and target depth (P = 0.23). The ease of use and precision of this stereotactic system support its development for clinical use in dogs with brain lesions > 3.31 mm.

Development of a technique for serial bilateral renal biopsy in steers.

A biopsy procedure was developed to provide serial kidney samples from standing steers. Ten clinically normal steers were given intramuscular injections of gentamicin sulfate, 4 mg/kg body weight. Renal biopsy was performed at 5 separate times. After feed was withheld for 24 h, laparoscopic surgery was performed in standing stocks. Acepromazine, xylazine, and butorphanol were used for sedation and analgesia, and 2% lidocaine was used for local anesthesia. Two incisions approximately 2 cm long were made in the paralumbar fossa to allow for trocar introduction. The abdomen was insufflated with CO2 and, with endoscopic guidance, a biopsy forceps used to remove a kidney sample 2 to 3 mm in diameter, by either a left or a right abdominal approach. Each operation was recorded on videotape, and images were also captured with a digital medical device system. Respiration, heart rate, temperature, appetite, attitude, and postural positions were evaluated at 12, 24, 48, and 72 h after surgery. The 51 laparoscopic procedures provided 48 renal samples (approximately 100 mg each). The 1st and 2nd samples were from the right kidney, and the 3rd sample was from either the left or the right kidney; the 4th and 5th samples were from the left kidney. Adhesions made an approach from the right side difficult for the 3rd sample. No clinical changes were observed in 9 steers after the procedure. One steer died after the 3rd procedure owing to hemorrhage.

Aerobic training, but not creatine supplementation, alters the gluteus medius muscle.

The aim of the present study was to investigate the effect of oral supplementation of creatine on the muscular responses to aerobic training. Twelve purebred Arabian horses were submitted to aerobic training for 90 d, with and without creatine supplementation, and evaluated with respect to BW and BCS and to the area and frequency of the different types of muscle fibers in the gluteus medius. Supplementation consisted of the daily administration of 75 g of creatine monohydrate mixed into the ration for the 90 d of training. Physical conditioning was conducted on a high-performance treadmill, and training intensity was stipulated by calculating the velocity at which blood lactate reaches 4 mmol/L, determined monthly for each animal. The individual intensity of physical force at 80% of aerobic threshold was established. Morphometry of gluteus medius muscle fibers was performed on frozen sections processed for histochemical analysis of myosin adenosine triphosphatase and immunohistochemistry of slow-contracting myosin. The results demonstrated that the animals maintained a moderate BCS without alteration of BW during the course of training, providing evidence of equilibrium between food intake and caloric expenditure during the study period. The present study demonstrated that aerobic training for 90 d caused hypertrophy of fiber types I (P = 0.04), IIA (P = 0.04), and IIX (P = 0.01), as well as an increase in the relative area occupied by type I fibers (P = 0.02) at the expense of type IIX fibers (P = 0.03), resulting in modifications of the contractile and metabolic characteristics of the gluteus medius muscle. It was not possible to show any beneficial effect from creatine on the skeletal muscle characteristics examined.

Use of abdominal ultrasonography in the diagnosis of primary hyperaldosteronism in a cat.

A 13-year-old castrated male cat was examined because of a 2-week history of weakness, cervical ventroflexion, and dysphagia. Clinicopathologic abnormalities included hypokalemia and high serum creatine kinase activity. Abdominal ultrasonography revealed a 15-mm spherical mass in the area of the left adrenal gland. Plasma aldosterone concentration was high, and plasma renin activity was low. Findings were diagnostic of primary hyperaldosteronism. The cat responded well to intravenous and oral potassium supplementation while in the hospital. The owner declined surgery; therefore, repeated follow-up abdominal ultrasonography was recommended. The cat did well clinically with medical management alone until day 334, when it was lost to follow-up.

Effect of endotoxin challenge on hepatic 5'-deiodinase activity in cattle.

Thyroid status is compromised in a variety of acute and chronic infections and toxin-mediated disease states. Conversion of thyroxine (T4) into the metabolically active hormone, triiodothyronine (T3), is catalyzed by 5'-deiodinase (5'D). Our objective was to determine the effect of endotoxin (LPS) challenge with and without L-arginine (Arg) infusion on hepatic activity of 5'D and plasma concentrations of T4 and T3. In a 2 x 2 factorial, beef heifers (275-310 kg b.wt.) were fed low (8% CP; 6.5 kg/d) or high (14% CP; 7.2 kg/d) isocaloric protein diets (1.96 Mcal/kg DM) for 10 d before LPS challenge. L-Arginine in saline (0.5 g/kg b.wt.) or saline alone was infused i.v. throughout an 8 hr period starting 2 hr before bolus LPS injection (Escherichia coli, 055: B5; 0.2 microg/kg; i.v.). Blood samples were collected at -2, 0, 3, 6, 12, and 24 hr relative to LPS injection. Liver samples were obtained 20 hr before, and then 6 and 24 hr after LPS challenge using a biopsy needle. Plasma T4 and T3 concentrations were not affected by dietary CP or Arg. Compared with levels at 0 hr, LPS challenge decreased plasma T4 (P < 0.01) and T3 (P < 0.001), respectively, 8.4% and 28.9% at 6 hr and 19.7% and 31.3% at 24 hr. Consistent with these changes, the T3:T4 ratio was lower than that at 0 hr (P < 0.001) 22.0% at 6 hr and 13.5% at 24 hr. Hepatic 5'D activities 20 hr before LPS injection were 2.80 +/- 0.11 nmol I- x hr(-1) x mg protein(-1) and decreased 24 hr after LPS, respectively, 45.4% (P < 0.01) and 17.6% (P < 0.05) in saline- and Arg-infused heifers. The results indicate that mild LPS challenge in cattle inhibits hepatic generation of T3 and decreases plasma concentrations of thyroid hormones. The data also suggest that the impact of LPS on 5'D activity in liver can be altered by Arg supplementation.

Effect of alpha-tocopherol deprivation on the involution of mammary gland in sheep.

The objective of this study was to investigate the effect of alpha-tocopherol deprivation on mammary gland involution and apoptosis in sheep. Two groups of four single lamb ewes were used. The control group received 100 mg/d of RRR-alpha-tocopherol supplementation and the experimental group received no vitamin E supplementation. After 3 mo of suckling, ewes were dried off, and blood samples from the jugular vein and tissue biopsies from the mammary gland were collected at d 1, 3, 5, and 8 after dry-off. The experimental group had lower plasma concentrations of alpha-tocopherol (1.8 vs. 4.2 micromol/L), lower glutathione peroxidase activity in erythrocytes, and higher concentration of malondialdehyde in plasma than the control group. Immunohistochemical analysis of tissue samples resulted in marked differences of bcl-2 and bax protein expressions during involution and between groups. The bax expression was decreased by alpha-tocopherol deprivation at 1, 3, and 5 d, but not at 8 d, while the bcl-2 score was higher only at 8 d (1.5 vs. 0.0 for experimental and control groups, respectively). As a result, the bcl-2 to bax ratios were increased for the experimental group at 1 and 8 d. During involution, apoptotic counts increased (from 0.12 to 4.06%), but no effects were detected in relation to bcl-2 to bax ratio and alpha-tocopherol. These results indicate that alpha-tocopherol can control bcl-2 expression, but not apoptosis in cells of the mammary gland during involution.

Putative effect of silymarin on sawfly (Arge pullata)-induced hepatotoxicosis in sheep.

The prevention of hepatotoxicity from sawfly larvae (Arge pullata) was studied in 8 lambs by using silymarin, a botanical compound isolated from Silybum marianum. Of 2 lambs dosed orally with larvae only, 1 had a marked toxic response whereas the other responded poorly as judged from clinical parameters, blood biochemistry and pathology. Two lambs treated with penicillin, glucose and silymarin 7 and 24 h after larvae dosing were not affected by toxicosis, whereas 2 lambs treated similarly but without silymarin responded intermediate to the other 2 groups. Our study suggests a favorable effect using silymarin in treatment of sawfly larvae-induced ruminant hepatotoxicosis.

Severe masseter myonecrosis in a horse.

A 6-year-old Quarter Horse was examined because of acute, severely swollen masseter muscles (palpation of which elicited pain response), exophthalmos, severe chemosis, and protrusion of the third eyelids. Blood selenium and vitamin E concentrations, and results of feed analysis and muscle biopsy supported a diagnosis of nutritional myopathy. The horse was treated and was clinically normal 2 weeks after discharge from the hospital.

Laparoscopic-assisted serial biopsy of the bovine kidney.

A serial renal biopsy with endoscopy was done, using 10 calves and a cow. In 8 of the calves, biopsy materials were collected 3 to 5 times over a period of 15 to 41 days. A laparoscope was inserted into the peritoneal cavity from the center of the right paralumbar fossa through the outer cannula of the trocar. Under laparoscopic observation, the renal parenchyma was collected with the cutting prong of a biopsy needle. Of 34 biopsy attempts, 32 were successful; in 2, there was incomplete penetration of the trocar assembly into the peritoneal cavity. In one instance, the trocar was misguided to the small intestine which was closely adherent to the peritoneum. The error may have been the result of the presence of a persistent blood clot resulting from the preceding biopsy. An immediate saline rinse of the blood clot attached to kidney and the surrounding tissues was effective in preventing such adhesions. The size of the average sample obtained was 1.5 mm in diameter and 16 mm (2 to 40 mm) long. The tissues were collected in 61 times from the 72 insertions of the biopsy needle to the renal tissue. The 11 unsuccessful attempts were caused by bluntness of the cutting parts of the needle. Adverse clinical signs were no observed after the serial biopsy of kidney, except for the presence of blood in he urine persisting for 1 to 5 days. Although a dehydrated blood clot was found in the renal pelvis of one animal at necropsy, any complication such as obstruction of urinary flow was not observed.