Oxytetracycline hydrochloride in the horse: serum, synovial, peritoneal and urine concentrations after single dose intravenous administration

Six adult mares were given a single intravenous injection of oxytetracycline HCl (50 mg/ml) at a dosage of 5 mg/kg. Serum, synovial fluid, peritoneal fluid, and urine oxytetracycline concentrations were measured serially over a 48-h period. The highest measured serum oxytetracycline concentration was 8.01 mcg/ml at 1/2 h. Oxytetracycline was detected in synovial fluid and peritoneal fluid, which obtained mean peak oxytetracycline concentrations of 4.43 mcg/ml and 4.20 mcg/ml, at 1/2 h and 1 h, respectively. These concentrations steadily declined in parallel with serum concentrations and were not measurable at 48 h. Urine oxytetracycline concentration was relatively high, with a peak concentration of 1565.2 mcg/ml at 1/2 h after drug administration.     

The radiological features of primary lung tumours in the dog: a review of thirty-six cases

Thirty dogs with primary lung tumours and six dogs with lymphomatoid granulomatosis were referred to the University of Bristol Veterinary School between 1970 and 1985. Clinical, radiographic and pathological findings were recorded in each case. Analysis of these findings allowed assessment of those features most helpful in reaching a definitive diagnosis and prognosis in such cases.     

Prospective Evaluation of Two Intracorporeally Sutured Prophylactic Laparoscopic Gastropexy Techniques Compared with Laparoscopic-Assisted Gastropexy in Dogs

Objective— To report technique, surgical time, complication rate, and postoperative activity in dogs undergoing 2 intracorporeally-sutured total laparoscopic gastropexy (TLG) techniques compared with a laparoscopic-assisted gastropexy (LAG) technique.
Study Design— Randomized clinical trial.
Animals— Dogs (n=30) weighing >25 kg.
Methods— Dogs were randomly assigned to 1 of 3 groups. Two TLG techniques were performed using a median 3 portal technique. One of 2 suturing techniques was used to approximate corresponding incisions made in the stomach and body wall; using intracorporeal hand-suturing or a suture-assist device (Endostitch^™). In a 3rd group, a previously reported LAG technique was used. All dogs had an activity monitor placed for 7 days pre- and postoperatively. Linear regression analyses were performed to evaluate the association of surgical procedure on gastropexy time and the percentage change in activity counts.
Results— Median gastropexy time was 28 minutes (range, 20–41 minutes) for LAG, 48 minutes (range, 39–61 minutes) for the hand suture TLG technique, and 56 minutes (range, 30–90 minutes) for the Endostitch^™ TLG technique. LAG was performed faster than TLG ( P <.05). LAG dogs had a greater decrease in postoperative activity than TLG dogs ( P =.005); however there was no difference in surgical time or postoperative activity between TLG techniques.
Conclusions— TLG can be performed safely and effectively in dogs and although it takes longer, it has less impact on postoperative activity compared with LAG.
Clinical Relevance— TLG techniques may have advantages over LAG as measured by a greater willingness of dogs to move around postoperatively.     

Pharmacokinetics of intravenous ceftiofur sodium and concentration in body fluids of foals

The objectives of this study were to determine pharmacokinetics of intravenous (i.v.) ceftiofur in foals, to compare ultra-high performance liquid chromatography tandem mass spectometry (UPLC-MS/MS) and microbiologic assay for the measurement of ceftiofur concentrations, and to determine the minimum inhibitory concentration ( MIC ) of ceftiofur against common equine bacterial pathogens. In a cross-over design, ceftiofur sodium was administered i.v. to six foals (1–2 days-of-age and 4–5 weeks-of-age) at dosages of 5 and 10 mg/kg. Subsequently, five doses of ceftiofur were administered i.v. to six additional foals between 1 and 5 days of age at a dose of 5 mg/kg q 12 h. Concentrations of desfuroylceftiofur acetamide (DCA), the acetamide derivative of ceftiofur and desfuroylceftiofur-related metabolites were measured in plasma, synovial fluid, urine, and CSF by use of UPLC-MS/MS. A microbiologic assay was used to measure ceftiofur activity for a subset of plasma samples. Following i.v. administration of ceftiofur at a dose of 5 mg/kg to 1–2 day-old foals, DCA had a t _½ of 7.8 ± 0.1 h, a body clearance of 74.4 ± 8.4 mL/h/kg, and an apparent volume of distribution of 0.83 ± 0.09 L/kg. After multiple i.v. doses at 5 mg/kg, DCA concentrations in CSF were significantly lower than concurrent plasma concentrations. Ceftiofur activity using a microbiologic assay significantly underestimated plasma concentrations of DCA. The MIC of ceftiofur required to inhibit growth of 90% of isolates of Escherichia coli , Pasteurella spp, Klebsiella spp, and β-hemolytic streptococci was <0.5 μg/mL. Intravenous administration of ceftiofur sodium at the rate of 5 mg/kg every 12 h would provide sufficient coverage for the treatment of susceptible bacterial isolates.     

Characterization of exotoxin produced by a shellfish-pathogenic Vibrio sp.

Abstract. Broth filtrate of a Vibrio species, isolated from spontaneously occurring epizootics among cultured oyster larvae, Crassostrea virginica (Gmelin), was shown to contain an exotoxin. Bioassays demonstrated that LC₅₀ value was less than 46.6 μg of toxin/l culture of oyster embryos. This quantity was produced by 2.9 × 10⁹ colony-forming units. Purified toxin showed neither proteolytic nor amylase activity; it did, however, demonstrate bacteriostatic capability. Studies showed that the toxin was heat-labile and that exposure to heat-produced toxoid had a beneficial effect on oyster embryonic development. Data revealed that although toxin was inactivated by heating, the bacteriostatic capability of the metabolite was not lost. Molecular weight of the toxin was estimated to be 68000.     

MICROBIAL POPULATIONS AND NITROGEN IN SOIL GROWING CONSECUTIVE CEREAL CROPS INFECTED WITH TAKE-ALL

Annually, for the past 12 years, a consecutive cereal-cropping sequence was begun. During 1969–72 soil was collected from plots with similar fertilizer treatments, but with different sequences of crops. In 1971 and 1972 wheat seedling bioassays showed that take-all disease became miximal after two or three crops, decreased to the fifth or sixth crop and then remained fairly constant in the‘take-all decline’state. The sequence with maximum disease had most NH₄⁺ -N and least NO₃^- -N in the rhizosphere soil in spring 1972, but there were no similar relationships in bulk soil in either of 2 years. Soil and rhizoplane populations of ammonifying and denitrifying bacteria were notably smaller in autumn 1970 and 1971 in short cereal sequences (2-5 yr.) than in the longer sequences. After γ-irradiating or autoclaving irradiated soils, all sequences contained much NH₄⁺ -N and although disease developing from added inoculum differed among soils, it did not follow the take-all decline pattern. Diffusate from sterilized soil favoured growth of the pathogen (Gaeumannomyces graminis var. tritici) least when it originated from the sequence that supported maximum disease.