Evaluation of renal gentamicin depletion kinetic properties in sheep, using serial percutaneous biopsies

Tissue drug residue research often involves the killing of an animal every time tissue concentrations are determined. To decrease the number of animals required to perform tissue depletion studies and to circumvent the statistical problems associated with determining tissue depletion kinetic properties, using multiple animals, the renal depletion profile of gentamicin from individual sheep was studied, using a bilateral renal translocation technique. Seven ewes were surgically altered, allowed to stabilize, and then allocated into 2 groups; group-1 sheep (n = 4) were given 3 mg of gentamicin/kg, IM, q 12 h for 10 days, and group-2 sheep (n = 3) were not given gentamicin. The kidneys from all ewes were biopsied 9 times over 74 days after the termination of gentamicin treatment. The renal concentrations of gentamicin were measured by use of a validated tissue digestion procedure coupled with a liquid-phase fluorescence polarization immunoassay. On days 75 and 77 after the end of gentamicin treatment, all ewes were euthanatized and necropsied. The concentrations of gentamicin in the biopsy specimens ranged from 71.9 to 183 micrograms/g on days 1 and 2 after dosing, and decreased to concentrations ranging from 3.99 to 7.35 micrograms/g on days 73 and 74 after the end of dosing. The decrease in renal gentamicin concentrations was best described by a biexponential equation. The early phase half-life was 2.8 days, whereas the terminal phase half-life was 59 days (harmonic means). There was no difference in the appearance or histologic features of the kidneys from groups 1 and 2. The only lesions noticed were linear fibroses that were attributed to the biopsy procedure.     

Production of a macrophage chemotactic factor by cultured jaagsiekte tumour cells

The increase of alveolar macrophages in jaagsiekte sheep lungs is not caused by excessive surfactant production but is due to a chemotactic factor secreted by the tumor cells. This factor has a molecular mass in the region of 13 kilodaltons, is stable at 56 degrees C but labile at 100 degrees C and, being sensitive to proteases, indicates that it is a small protein molecule.     

Comparison of surface diameters and dissected diameters of bovine ovarian follicles

Comparisons were made between diameters of 54 bovine follicles greater than 5.9 mm from 32 pairs of ovaries measured on the ovarian surface and diameters of the same follicles subsequently dissected from the ovaries. Seventy-eight percent of follicles measured on the ovarian surface were within 1.9 mm of the size measured after dissection. The remaining 22% of follicles measured on the surface had diameters recorded that were 2.0 to 3.9 mm different than their diameter after dissection. Surface diameter tended to underestimate dissected diameter for small follicles (less than 8.0 mm) and to overestimate dissected diameter for large (greater than or equal to 12.0 mm) follicles. The correlation coefficient between surface and dissected follicular diameters was .83. We conclude that measuring the diameter of the largest follicles on the ovarian surface and after dissection yield approximately equivalent results.     

Antimuscarinic premedication in canine anaesthesia: a comparison of atropine, hyoscine and glycopyrrolate

Anticholinergic drugs are commonly given as preanaesthetic medication to reduce secretions and bradycardia. In this trial, clinical cases were given atropine, hyoscine or glycopyrrolate on a logarithmic dose scale. Another group was not given any anticholinergic agent. Anaesthesia was induced with thiopentone and maintained with halothane in oxygen and nitrous oxide. All the anticholinergic drugs decreased salivation although there was also a small fall in salivation in the control group. Pulse rates rose on induction and fell over the course of anaesthesia in the control group but the mean pulse rates did not fall below the normal range. Atropine and hyoscine produced a tachycardia followed by a fall in pulse rate similar to the control group during anaesthesia. Glycopyrrolate maintained the pulse at the same level throughout. In view of the disadvantages of tachycardia, glycopyrrolate is probably the anticholinergic agent of choice when such a drug is indicated.     

Temporary indwelling rectal liner for use in horses with rectal tears

A temporary indwelling liner was surgically installed in 17 horses with grade III or grade IV rectal tears. The rectal tears of 9 of the horses healed. The remaining 8 horses developed peritonitis as a result of peritoneal contamination before surgery, a change in grade of the tear, or material failure.     

Corynebacterium equi: An interhost review with emphasis on the foal

A review of the recent and/or significant literature concerning Corynebacterium equi, including its morphologic, biochemical, immunological, and pathological characteristics in the foal, humans and other animals is presented. The similarity in the tissue responses of mammalian hosts to C. equi and Mycobacterium spp. is discussed.

The antigenic structure and virulence factors associated with C. equi. other corynebacteria and mycobacteria are compared.

The immunological aspects of resistance to C. equi are considered. The evidence suggests that the major immune response elicited in the foal by C. equi is cell-mediated. However, the immunopathogenic mechanism needs clarification. Areas of future research are suggested.