Cardiopulmonary, blood and peritoneal fluid alterations associated with abdominal insufflation of carbon dioxide in standing horses.

REASONS FOR PERFORMING STUDY: Abdominal insufflation is performed routinely during laparoscopy in horses to improve visualisation and facilitate instrument and visceral manipulations during surgery. It has been shown that high-pressure pneumoperitoneum with carbon dioxide (CO2) has deleterious cardiopulmonary effects in dorsally recumbent, mechanically ventilated, halothane-anaesthetised horses. There is no information on the effects of CO2 pneumoperitoneum on cardiopulmonary function and haematology, plasma chemistry and peritoneal fluid (PF) variables in standing sedated horses during laparoscopic surgery. OBJECTIVES: To determine the effects of high pressure CO2 pneumoperitoneum in standing sedated horses on cardiopulmonary function, blood gas, haematology, plasma chemistry and PF variables. METHODS: Six healthy, mature horses were sedated with an i.v. bolus of detomidine (0.02 mg/kg bwt) and butorphanol (0.02 mg/kg bwt) and instrumented to determine the changes in cardiopulmonary function, haematology, serum chemistry and PF values during and after pneumoperitoneum with CO2 to 15 mmHg pressure for standing laparoscopy. Each horse was assigned at random to either a standing left flank exploratory laparoscopy (LFL) with CO2 pneumoperitoneum or sham procedure (SLFL) without insufflation, and instrumented for measurement of cardiopulmonary variables. Each horse underwent a second procedure in crossover fashion one month later so that all 6 horses had both an LFL and SLFL performed. Cardiopulmonary variables and blood gas analyses were obtained 5 mins after sedation and every 15 mins during 60 mins baseline (BL), insufflation (15 mmHg) and desufflation. Haematology, serum chemistry analysis and PF analysis were performed at BL, insufflation and desufflation, and 24 h after the conclusion of each procedure. RESULTS: Significant decreases in heart rate, cardiac output and cardiac index and significant increases in mean right atrial pressure, systemic vascular resistance and pulmonary vascular resistance were recorded immediately after and during sedation in both groups of horses. Pneumoperitoneum with CO2 at 15 mmHg had no significant effect on cardiopulmonary function during surgery. There were no significant differences in blood gas, haematology or plasma chemistry values within or between groups at any time interval during the study. There was a significant increase in the PF total nucleated cell count 24 h following LFL compared to baseline values for LFL or SLFL at 24 h. There were no differences in PF protein concentrations within or between groups at any time interval. CONCLUSIONS: Pneumoperitoneum with CO2 during standing laparoscopy in healthy horses does not cause adverse alterations in cardiopulmonary, haematology or plasma chemistry variables, but does induce a mild inflammatory response within the peritoneal cavity. POTENTIAL RELEVANCE: High pressure (15 mmHg) pneumoperitoneum in standing sedated mature horses for laparoscopic surgery can be performed safely without any short-term or cumulative adverse effects on haemodynamic or cardiopulmonary function.

Pharmacokinetics of fluconazole following intravenous and oral administration and body fluid concentrations of fluconazole following repeated oral dosing in horses.

OBJECTIVE: To determine the pharmacokinetics of fluconazole in horses. ANIMALS: 6 clinically normal adult horses. PROCEDURE: Fluconazole (10 mg/kg of body weight) was administered intravenously or orally with 2 weeks between treatments. Plasma fluconazole concentrations were determined prior to and 10, 20, 30, 40, and 60 minutes and 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, and 72 hours after administration. A long-term oral dosing regimen was designed in which all horses received a loading dose of fluconazole (14 mg/kg) followed by 5 mg/kg every 24 hours for 10 days. Fluconazole concentrations were determined in aqueous humor, plasma, CSF, synovial fluid, and urine after administration of the final dose. RESULTS: Mean (+/- SD) apparent volume of distribution of fluconazole at steady state was 1.21+/-0.01 L/kg. Systemic availability and time to maximum plasma concentration following oral administration were 101.24+/-27.50% and 1.97+/-1.68 hours, respectively. Maximum plasma concentrations and terminal half-lives after IV and oral administration were similar. Plasma, CSF, synovial fluid, aqueous humor, and urine concentrations of fluconazole after long-term oral administration of fluconazole were 30.50+/-23.88, 14.99+/-1.86, 14.19+/-5.07, 11.39+/-2.83, and 56.99+/-32.87 microg/ml, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Bioavailability of fluconazole was high after oral administration to horses. Long-term oral administration maintained plasma and body fluid concentrations of fluconazole above the mean inhibitory concentration (8.0 mg/ml) reported for fungal pathogens in horses. Fluconazole may be an appropriate agent for treatment of fungal infections in horses.

Tissue strength and wound morphology of the equine linea alba after ventral median celiotomy.

OBJECTIVE: To evaluate the tensile strength and wound morphology of the equine linea alba at intervals over 6 months after ventral median celiotomy. STUDY DESIGN: Linea alba tensile strength and wound morphology were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Linea alba samples from 3 unoperated horses were used as controls. ANIMALS: Eighteen adult horses, weighing 400 to 500 kg, 4 to 15 years old. METHODS: Tensile strength and thickness of incised linea alba samples collected at 2, 4, 8, 16, and 24 weeks after ventral median celiotomy were compared with control linea alba samples. Additional samples were subjectively evaluated for wound morphology, notably collagen morphology. RESULTS: Control linea alba had a mean (+/-SEM) tensile strength of 484.9 +/- 58.3 N and was significantly (P < or = .05) stronger than at 2 weeks (87.7 +/- 61.4 N) after surgery. The tensile strength of 4-week (305.8 +/- 61.7 N), 8-week (465.4 +/- 56.5 N), and 16-week (477.8 +/- 57.2 N) samples were not significantly different from control linea alba. At 24 weeks, the tensile strength (721.0 +/- 57.9 N) was significantly stronger than control. The 2-, 4-, and 8-week samples were significantly thicker than controls, whereas the 16- and 24-week samples were not different from controls. On microscopy, control samples were characterized by dense mature collagen bundles. At 2 weeks, samples consisted primarily of granulation tissue, whereas at 4 weeks, samples had immature collagen fibers that were not formed into bundles, and at 8, 16, and 24 weeks, all samples had abundant mature collagen fibers formed into bundles. CONCLUSIONS: At 8 weeks, incised and sutured equine linea alba had a tensile strength comparable with non-incised linea alba and was characterized by mature collagen. CLINICAL RELEVANCE: Based on tensile strength and wound morphology, horses that have had an uncomplicated recovery after ventral median celiotomy should be able to return to controlled exercise as early as 60 days after surgery.

Closed one-stage functional end-to-end jejunojejunostomy in horses with use of linear stapling equipment.

OBJECTIVE: To use gastrointestinal linear stapling instrumentation to perform a closed one-stage functional end-to-end jejunojejunostomy in adult horses as an alternative to a stapled side-to-side jejunojejunostomy. STUDY DESIGN: Clinical outcome, anatomic and histological architecture, and anastomotic dimensions were determined at 2, 4, 8, 16, and 24 weeks postoperatively. ANIMALS OR SAMPLE POPULATION: 18 adult horses. METHODS: The anastomosis and peritoneal cavity were inspected for adhesions. The diameter and circumference of the anastomosis and jejunum oral and aboral to the anastomosis were determined from digitized contrast radiographs and linear measurements. Healing of anastomotic sites was evaluated histologically. RESULTS: Three horses were euthantized in the immediate postoperative period. In the 15 surviving horses, there were no peritoneal adhesions or distortion of the anastomoses and stomas remodeled in an end-to-end fashion. The mean anastomotic staple line (7.48 cm) and mucosa (6.89 cm) diameters were significantly (P < .05) larger than the mean jejunal diameter oral (6.03 cm) and aboral (6.01 cm) to the anastomosis. The mean anastomotic luminal circumference (13.61 cm) was significantly (P < .01) larger than the mean oral (11.43 cm) and aboral (11.12 cm) jejunal circumference. Histologically, there was adequate mucosal and muscularis mucosae reapposition with a moderate degree of fibrosis and inflammation. CONCLUSIONS: Closed one-stage functional end-to-end jejunojejunostomy resulted in an acceptable functional anastomosis. CLINICAL RELEVANCE: This technique appears to be an acceptable alternative to linearly stapled, side-to-side jejunojejunostomies performed in horses.

Epididymal swelling attributable to generalized lymphosarcoma in a stallion.

Aspermia was diagnosed in a 12-year-old Thoroughbred stallion with generalized lymphosarcoma. Invasion of the epididymus by neoplastic cells caused thickening and enlargement of both epididymes. The testes were not affected. The nodular ultrasonographic architecture was similar to that in previously reported cases of infectious epididymitis.

Cytogenetic studies of human brain tumors and their clinical significance. II. Meningioma.

Cytogenetic study of 45 meningiomas from 31 female and 14 male patients are reported. No chromosomal abnormalities were found in nine (20%). These were predominantly meningotheliomatous, and were from younger patients (average age, 46 years). Monosomy 22 was noted in only 20% and in 12 patients (27%) with other losses and rearrangements. Among the latter, 50% were either recurrent or recurrent and invasive, the majority were fibromatous and occurred in older patients. Nonrandom loss was observed of the Y and abnormalities of chromosomes #1, #7, and #14 and, to a lesser extent, chromosomes #18, #19, and #20. Meningiomas may begin with no chromosomal abnormalities, having meningotheliomatous histopathologic appearance, occur in younger patients, and are less aggressive. Karyotypic evolution following loss of a chromosome #22 continues with losses and rearrangements of other chromosomes with apparent nonrandom involvement of chromosomes #1, #7, #14 and Y. This karyotypic change is associated with aggressive tumor behavior and fibromatous morphology.

Cytogenetic studies of human brain tumors and their clinical significance. 1. Medulloblastoma.

Four medulloblastomas were studied cytogenetically with clinical follow-up of the patients. Three of these lesions were diploid and the patients manifested no recurrence at 40, 37 and 36 months respectively. The remaining tumor was aneuploid with 52 chromosomes and the patient expired of the medulloblastoma in 7 months. These findings are compared to nine previously reported karyotypes of primary medulloblastomas only two of which had clinical follow-up of the patients. On the basis of our results and these previously reported cases it appears that medulloblastomas with a diploid chromosomal pattern have a better prognosis than those with aneuploidy.

Pregnancy and the herniated lumbar disc.

During the last decade, five pregnant patients with symptoms and signs of a herniated lumbar disc were identified among a series of 48,760 consecutive deliveries at William Beaumont Hospital, an incidence of 1:10,000. In all cases, clinical evaluation and electromyography complemented conservative treatment during the final stage of pregnancy. Each patient was delivered by cesarean section. Large lumbar disc herniations in each case were subsequently identified by myelography. In all five cases, lumbar laminectomy was successful in facilitating the eventual resolution of the signs and symptoms of the radiculopathy. Although the mechanical and postural stresses of pregnancy have been cited as predisposing causes of a herniated lumbar disc, this study suggests otherwise. Lumbosacral vertebral disc ruptures of pregnancy, while relatively rare, should nevertheless be recognized early, distinguished from other causes of lumbosacral gestational plexopathy, and promptly treated.

Scrotal measurements in beef bulls: heritability estimates, breed and test station effects.

Heritability estimates for scrotal circumference and testicular tone at weaning (225 d) and yearling (365 d) were determined from records on 565 bulls from a purebred Angus herd; year, station and breed effects were determined from scrotal circumference records on 2,420 bulls at five tests stations. Year, breed and breed X year effects on scrotal circumference, length, width and volume were determined from records on 347 bulls at one station. Heritability estimates (+/- SE) were .60 +/- .17, .28 +/- .18 and .25 +/- .18 for weaning scrotal circumference, right and left tone, and .38 +2- .16, .72 +/- .18 and .52 +/- .17 for yearling scrotal circumference, right and left tone, respectively. With the exception of low negative correlations of 205-d weight and longissimus muscle area with yearling scrotal circumference (-01 and -.02, respectively), correlations of growth and live-estimated carcass traits with weaning or yearling scrotal dimensions were low and positive (0.8 to .35). In the second data set, Simmental and Angus had greater (p less than .01) yearling scrotal circumferences than Charolais or Herefords; means were 35.3, 35.0, 33.7 and 33.5 cm, respectively. Station and station x breed effects were significant (P less than .01), with the latter effect indicating that breeds did not rank similarly in scrotal circumference at different test stations. In the third data set, scrotal circumference and volume were essentially the same as scrotal length and width in ranking breeds. year X breed interactions were nonsignificant for all scrotal traits, indicating that breeds were ranked similar in different years with respect to scrotal dimensions. These results indicate that bulls of different breeds should not be compared to established standards; a more acceptable procedure would be the use of deviations from the respective breed-station-year means.

Brain abscess as a complication of halo traction.

The occurrence of a brain abscess as a complication of halo traction and immobilization in the management of scoliosis is reported. Previous reports suggest that this complication is rare. Unique in this case is the development of an intracerebral abscess without skull perforation by the halo device and without evidence of contiguous spread of infection. Attention of clinical signs (headache) and the use of computerized axial tomography may allow for early detection and appropriate care.