Determination of oral tramadol pharmacokinetics in horses

The determination of the pharmacokinetic parameters of tramadol in plasma and a better characterization of its metabolites after oral administration to horses is necessary to design dosage regimens to achieve target plasma concentrations that are associated with analgesia. The purpose of this study was to determine the pharmacokinetics and elimination pattern in urine of tramadol and its metabolites after oral administration to horses. Tramadol was administered orally to six horses and its half-life, T_max and C_max in plasma were 10.1, 0.59 h, and 132.7 ng/mL, respectively. The half-life, T_max and C_max for M1 in plasma were 4.0, 0.59 h, and 28.0 ng/mL, respectively. Tramadol and its metabolites were detectable in urine between 1 and 24 h after the administration. In conclusion, the PK data reported in this study provides information for the design of future studies of tramadol in horses.     

Wool production of sheep chronically infected with Haemonchus contortus

A chronic infection was established in a group of twenty 18-month-old non-reproductive Merino ewes by oral administration of 3000 infective H. contortus larvae twice weekly for 12 weeks. Their live-weights and wool production were compared with those of 20 uninfected ewes grazing the same pasture. In the infected sheep, faecal egg counts increased over a period of 9 weeks to reach a mean of 5000 eggs per gram, accompanied by small, but significant effects on packed-cell volume and live-weight. The effects of infection on wool growth were also small, and not statistically significant, although there was evidence of a faster seasonal decline in wool growth in infected sheep. It was concluded that mortality induced by acute infection is the most important economic effect of this parasite.     

Arthrotomy versus arthroscopy and partial synovectomy for treatment of experimentally induced infectious arthritis in horses.

To evaluate the clinical, laboratory, and histologic effects of 2 methods of treatment for infectious arthritis in horses, Staphylococcus aureus (3.4 to 3.9 x 10(3) colony-forming units) was inoculated into the tarsocrural joints of 8 horses on day 0. Each horse was treated with phenylbutazone (2 g, PO, q 24 h) and gentamicin sulfate (2.2 mg/kg of body weight, IV, q 8 h) for 14 days. On day 2, general anesthesia was induced, and each horse had 1 tarsocrural joint treated by arthrotomy, with removal of accessible fibrin and lavage with 3 L of sterile balanced electrolyte solution. An indwelling plastic drain was placed in the standing horse to provide a means for lavage with 3 L of balanced electrolyte solution twice daily for 72 hours. The contralateral tarsocrural joint was treated via arthroscopic debridement, synovectomy, and lavage with 3 L of balanced electrolyte solution. Arthrotomy and arthroscopic portals were allowed to heal by second intention. Lameness and thermographic examinations, analysis and bacteriologic culture of synovia, CBC, and WBC differential count were performed prior to inoculation and on days 1, 3, 6, 8, and 13. On day 14, each horse was euthanatized, and the joints were measured, opened, and photographed. Synovium and articular cartilage were obtained for semiquantitative histologic (H&E stain) and histochemical (safranin O fast green stain) evaluation. Lameness and joint circumference were significantly (P less than 0.05) greater in limbs treated by arthroscopy, synovectomy, and lavage. Arthrotomy with lavage eliminated the S aureus infection significantly (P less than 0.05) earlier than arthroscopy, synovectomy, and lavage, however, both treatments eliminated the infection in all but a single joint.(ABSTRACT TRUNCATED AT 250 WORDS)     

Incidence of molds and mycotoxins in commercial animal feed mills in seven midwestern states, 1988-1989.

A total of 82 feed manufacturers located within seven midwestern states (Iowa, Nebraska, Minnesota, Illinois, Indiana, Ohio, Michigan) participated in a survey of mold and mycotoxin contamination of corn. Samples were submitted from a composite of the grading samples taken from each incoming load of corn. The survey was initiated in July 1988. During the 12-mo period, moisture content of the corn samples upon receipt at the laboratory ranged from 10.5 to 13.3%. The greatest variation occurred in the springtime. Iowa's corn samples were driest (11.2%), and samples submitted from Ohio were wettest (12.8%). Mold counts averaged 2.63 x 10(4) per gram during the year. The predominant mold found was Fusarium sp. Samples were checked by black light and averaged 25.4% positive during the period. When assayed for mycotoxins, 19.5% of the samples were positive for at least one of the following: aflatoxin, zearalenone, T2 toxin and deoxynivalenol (vomitoxin). Aflatoxin and T2 toxin made up the majority of these samples containing toxin. The highest incidence of mycotoxin-contaminated corn (48%) occurred in samples submitted in July of 1988. Over the 12-mo period, the highest mycotoxin contamination occurred in Iowa, Illinois and Michigan. When samples were subjected to 90% relative humidity and 32 degrees C, an average of 3.9 d was required for mold growth to appear. After incubation, 24.7% of the samples contained one of the four toxins. The data indicate that mold and mycotoxin contamination of mixed samples of corn is widespread, even in the midwestern corn belt of the U.S.     

Baroreceptor control of heart rate in chickens (Gallus domesticus)

The baroreceptor control of heart rate was examined in nonanesthetized, nonrestrained, White Leghorn chickens (n = 10) by measuring the heart period response to modest increases in systolic blood pressure induced by IV boluses of phenylephrine (0.04 micrograms/g). In each animal, a sciatic artery and a femoral vein were chronically instrumented for the measurement of blood pressure and heart rate, together with venous access. Sustained and consistent cardiac slowing was seen in all chickens in response to small increases in systolic pressure. The mean slope of the regression equation between heart period and systolic pressure was 13.9 +/- 0.8 s X 10(-4)/mm of Hg. This sensitivity was reduced to 2.1 +/- 1.5 s X 10(-4)/mm of Hg by anesthetizing the chickens with isoflurane (inspired concentrations of 1%).     

Porcine-specific CpG-oligodeoxynucleotide activates B-cells and increases the expression of MHC-II molecules on lymphocytes

Two CpG-oligodeoxynucleotide motifs, a mouse-specific one (CpG(mouse)) 5'-GCTAGACGTTAGCGT-3' and a porcine-specific one (CpG(pig)), 5'-TGCATCGATGCAG-3' were synthesized by two different companies and tested in vitro for their capacity to stimulate porcine peripheral blood monomorphonuclear cells (PBMC). The porcine-specific motif, consisting of a nuclease-resistant phosphorothioate guanosines at the 5' and at the 3'-end (CpG(pig)-S), enhanced significantly the proliferation of porcine PBMC in comparison with CpG(mouse). The latter motif did not induce any proliferation. Methylation of CpG(pig) diminished the proliferation. Four days of culture with CpG(pig)-S increased the percentage of B-cells as well as B-cell blasting. Moreover, CpG(pig)-S also enhanced the expression of class II MHC in most cultures while there were no changes in percentage of macrophages or in the degree of expression of the macrophage marker (monoclonal 74-22-15). In conclusion, in this study, it was confirmed that 5'-ggTGCATCGATGCAGggggg-3' is a swine-specific CpG-ODN, that activates porcine B-cells and deserves further evaluation in vivo as a potential immunostimulating adjuvant.     

Recovery of Campylobacter jejuni in feces and semen of caged broiler breeder roosters following three routes of inoculation

We previously reported the recovery of Campylobacter (naturally colonized) from the ductus deferens of 5 of 101 broiler breeder roosters, and four of those five positive roosters had previously produced Campylobacter-positive semen samples. Those results prompted further evaluation to determine if inoculation route influenced the prevalence or level of Campylobacter contamination of semen, the digestive tract, or reproductive organs. Individually caged roosters, confirmed to be feces and semen negative for Campylobacter, were challenged with a marker strain of Campylobacter jejuni either orally using 1.0 ml of a diluted cell suspension (log(10)4.3 to 6.0 cells), by dropping 0.1 ml of suspension (log(10)5.3 to 7.0 cells) on the everted phallus immediately after semen collection or by dip coating an ultrasound probe in the diluted cell suspension (log(10)4.3 to 6.0 cells) and then inserting the probe through the vent into the colon. Six days postinoculation, individual feces and semen samples were again collected and cultured for Campylobacter. Seven days postinoculation, roosters were killed, the abdomen aseptically opened to expose the viscera, and one cecum, one testis, and both ductus deferens were collected. The samples were then suspended 1:3 (weight/volume) in Bolton enrichment broth for the culture of Campylobacter. Samples were also directly plated onto Cefex agar to enumerate Campylobacter. Campylobacter was recovered 6 days after challenge from feces in 82% of samples (log(10)4.1 colony-forming units [CFU]/g sample), 85% of semen samples (log(10)2.9 CFU/ml), and on the seventh day postchallenge from 88% of cecal samples (log(10)5.8 CFU/g sample). Campylobacter was not directly isolated from any testis sample but was detected following enrichment from 9% (3/33) of ductus deferens samples. Roosters challenged with Campylobacter orally, on the phallus, or by insertion of a Campylobacter dip-coated ultrasound probe were all readily colonized in the ceca and produced Campylobacter-positive semen and feces on day 6 after challenge. The low prevalence of recovery of Campylobacter from the ductus deferens samples and failure to recover from any testis sample suggests that semen may become Campylobacter positive while traversing the cloaca upon the everted phallus. The production of Campylobacter-positive semen could provide a route in addition to fecal-oral for the horizontal transmission of Campylobacter from the rooster to the reproductive tract of the hen.