Of mice and men: olfactory neuroblastoma among animals and humans

Olfactory neuroblastoma (ONB) is a rare tumour of nasal cavity and paranasal sinuses that arises from the olfactory neuroepithelium and has unpredictable clinical course. As the sense of smell is phylogenetically one of the first senses and olfactory neuroepithelium is evolutionary conserved with striking similarities among different species, we performed an extensive analysis of the literature in order to evaluate the similarities and differences between animals and humans on the clinical, morphological, immunohistochemical, ultrastructural and molecular level. Our analysis revealed that ONB was reported mainly in mammals and showed striking similarities to human ONB. These observations provide rationale for introduction of therapy modalities used in humans into the veterinary medicine. Animal models of neuroblastoma should be considered for the preclinical studies evaluating novel therapies for ONB.     

Evaluation of tizanidine as a marker of canine CYP1A2 activity

The dog CYP1A2 enzyme is likely an important contributor to the metabolism of veterinary drugs. Dog CYP1A2 is expressed in liver, plus it is inducible and polymorphic, creating the potential for intersubject differences in pharmacokinetics. Hence, the ability to probe dog CYP1A2 activity and inhibition is relevant toward veterinary drug development and drug–drug interaction assessment. Previous studies have relied on human probes with questionable specificity for CYP1A2, so it was hypothesized that recombinant CYP1A2 could be used to find a specific CYP1A2 substrate. Intrinsic clearance experiments demonstrated that tizanidine was a substrate of CYP1A2. Profiling of tizanidine metabolites generated by CYP1A2 identified the imidazole metabolite that was detectable in dog plasma. The imidazole metabolite was subsequently used to evaluate tizanidine as a CYP1A2 probe. Co‐administration of the CYP1A inhibitor enrofloxacin with tizanidine significantly decreased (30%; n = 3) the formation of the imidazole metabolite vs. control experiments. As enrofloxacin is a weak inhibitor, further studies are required to confirm the sensitivity of tizanidine as an in vivo probe. However, tizanidine may be a more selective CYP1A2 probe than phenacetin when conducting in vitro studies due to the presence of other phenacetin‐metabolizing enzymes in dog liver microsomes.     

Pharmacokinetic indices for cefovecin after single‐dose administration to adult sea otters (Enhydra lutris)

Seven sea otters received a single subcutaneous dose of cefovecin at 8 mg/kg body weight. Plasma samples were collected at predetermined time points and assayed for total cefovecin concentrations using ultra‐performance liquid chromatography and tandem mass spectrometry. The mean (±SD) noncompartmental pharmacokinetic indices were as follows: C_Max (obs) 70.6 ± 14.6 μg/mL, T_{Max (obs)} 2.9 ± 1.5 h, elimination rate constant (k_el) 0.017 ± 0.002/h, elimination half‐life (t_1/2kel) 41.6 ± 4.7 h, area under the plasma concentration‐vs.‐time curve to last sample (AUC_last) 3438.7 ± 437.7 h·μg/mL and AUC extrapolated to infinity (AUC_0→∞) 3447.8 ± 439.0 h·μg/mL. The minimum inhibitory concentrations (MIC) for select isolates were determined and used to suggest possible dosing intervals of 10 days, 5 days, and 2.5 days for gram‐positive, gram‐negative, and Vibrio parahaemolyticus bacterial species, respectively. This study found a single subcutaneous dose of cefovecin sodium in sea otters to be clinically safe and a viable option for long‐acting antimicrobial therapy.     

Abusive use of antibiotics in poultry farming in Cameroon and the public health implications

1. The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined.

2. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics.

3. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined.

4. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities.

5. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues.

6. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested.

7. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

     

Effect of supplementing broiler chicken diets with green tea extract on the growth performance,lipid profile,antioxidant status and immune response

1. A trial was conducted to explore the effect of feeding graded concentrations of green tea extract (GTE; 125, 250, 500, 1000 and 2000 mg/kg) on the growth performance, serum lipid profile, liver glutathione-reduced, thigh muscle malondialdehyde and humoral immune response against Newcastle disease virus vaccines of broiler chickens from hatching to 42 d of age. The results of broilers fed on GTE were contrasted to those fed on butylated hydroxytoluene (BHT; 125 mg/kg) or unsupplemented controls.

2. The obtained results revealed no significant difference among treatments in the measured growth performance parameters (body weight, average daily gain, average daily feed intake and feed conversion ratio), per cent liveability and serum lipid profile (total lipid, total cholesterol, high-density, low-density and very low-density lipoprotein cholesterols).

3. Dietary intake of GTE resulted in a significant increase in the liver glutathione-reduced level compared to the control. The glutathione-reduced level of broilers fed on the BHT diet was not significantly different from that of broilers fed on GTE or control diets. Feeding GTE or BHT resulted in a significant decrease in the malondialdehyde level of meat tissue.

4. The specific antibody titre against Newcastle disease virus vaccines was significantly increased at 28 and 35 d of age in broilers fed on diets supplemented with GTE but not with BHT.

5. In conclusion, GTE was found to possess antioxidant and immunostimulant characteristics for broilers when supplemented to their diets, and its optimum inclusion level ranged from 125 to 500 mg/kg.