Failure to respond to endogenous or exogenous melatonin may cause nonphotoresponsiveness in Harlan Sprague Dawley rats

Background  

Responsiveness to changing photoperiods from summer to winter seasons is an important but variable physiological trait in most temperate-zone mammals. Variation may be due to disorders of melatonin secretion or excretion, or to differences in physiological responses to similar patterns of melatonin secretion and excretion. One potential cause of nonphotoresponsiveness is a failure to secrete or metabolize melatonin in a pattern that reflects photoperiod length.     

Evaluation of a long‐acting injectable formulation of omeprazole in healthy dogs

BackgroundTo evaluate the efficacy of a single intramuscular adminsitration of long‐acting omeprazole (LA‐OMEP) in increasing gastric pH in dogs.HypothesisWe hypothesized that LA‐OMEP would meet in healthy dogs the clinical goals defined for human patients for treatment of gastroduodenal ulceration.AnimalsNine healthy research dogs.MethodsProspective experimental study. Dogs were given a 4 mg/kg intramuscular injection of LA‐OMEP. Intragastric pH was continuously recorded on treatment days 0 to 7. Daily mean pH and mean percentage time (MPT) intragastric pH was ≥3 or ≥4 were determined.ResultsThe mean onset of action for the LA‐OMEP was 98.11 min (SD 46.39). The mean number of days the dogs'' pH met established goals for MPT pH ≥3 was 5.5 days (range, 3‐7) and 5.25 days for MPT pH ≥4 (range, 3‐7). Long‐acting omeprazole met the human clinical goals pH ≥3 for 72 hours in 8/8 of the dogs and MPT pH ≥4 for 96 hours in 7/8 of dogs.Conclusions and Clinical ImportanceThe LA‐OMEP formulation produced gastric acid suppression in healthy dogs for an average of 5 days and up to 7 days, after a single intramuscular injection. No major adverse effects were observed.     

A Non‐Reciprocal Autosomal Translocation 64,XX,t(4;10)(q21;p15) in an Arabian Mare with Repeated Early Embryonic Loss

Balanced autosomal translocations are a known cause for repeated early embryonic loss (REEL) in horses. In most cases, carriers of such translocations are phenotypically normal, but the chromosomal aberration negatively affects gametogenesis giving rise to both genetically balanced and unbalanced gametes. The latter, if involved in fertilization, result in REEL, whereas gametes with the balanced form of translocation will pass the defect into next generation. Therefore, in order to reduce the incidence of REEL, identification of translocation carriers is critical. Here, we report about a phenotypically normal 3‐year‐old Arabian mare that had repeated resorption of conceptuses prior to day 45 of gestation and was diagnosed with REEL. Conventional and molecular cytogenetic analyses revealed that the mare had normal chromosome number 64,XX but carried a non‐mosaic and non‐reciprocal autosomal translocation t(4;10)(q21;p15). This is a novel translocation described in horses with REEL and the first such report in Arabians. Previous cases of REEL due to autosomal translocations have exclusively involved Thoroughbreds. The findings underscore the importance of routine cytogenetic screening of breeding animals.     

Greenhouse gas emissions from decomposition of biosolids as affected by stabilization method and soil moisture

Computational models are useful to estimate agricultural greenhouse gas emissions at regional scales. However, empirically based parameter values are required for the models to accurately represent carbon (C) and nitrogen (N) mineralization rates of different organic amendments in more and less humid regions or during wet and dry periods of the growing season. A controlled environment study was conducted to assess the rates of C and N mineralization in differently processed sewage sludge (biosolids) in wet and dry soil. Parameter values were estimated for use in modelling the degradation of three types of biosolids. A loam soil with either 49% water-filled pore space (WFPS) or 29% WFPS was amended with mesophilic anaerobically digested (digested), alkaline-stabilized, or composted biosolids. Headspace samples were collected and analysed for carbon dioxide (CO₂) and nitrous oxide (N₂O), and soil samples for nitrate (${\mathrm{NO}}_3^{-}$) and ammonium (${\mathrm{NH}}_4^{+}$). Four different first-order models were fitted to the cumulative CO₂–C and N₂O–N data (R² > 0.98), and soil ${\mathrm{NO}}_3^{-}$ (R² > 0.65) and ${\mathrm{NH}}_4^{+}$ (R² > 0.93) concentrations. CO₂–C data indicated that C mineralization was higher in soil with 49% WFPS than in soils with 29% WFPS. Seventy-nine percent of the C compounds in digested biosolids degraded in soil with 49% WFPS, compared with 52% for alkaline-stabilized biosolids and 8% for composted biosolids. The fitted coefficient values were similar for all of the four first-order models used in this study and provide useful information for parameterizing more sophisticated mechanistic models of the degradation of biosolids in soil.