Immunopathological aspects of canine renal disease

It is now becoming clear that the development of immunity against an infectious agent is not always beneficial to the host and may sometimes be instrumental in exacerbating the disease process. Thus, it is important to define the nature of the immunological processes which undoubtedly play an important role in some of the important renal diseases of the dog.
Deposition of immune complexes in the glomeruli stimulates a range of morphological types of glomerulonephritis. The persistence of leptospiral antigen, alone or complexed with locally produced antibody, in the renal interstitium appears to be responsible for the marked cellular response in acute leptospiral nephritis. In chronic forms of diffuse renal disease, glomerular immune complexes have been detected in chronic glomerulonephritis but not with certainty in chronic interstitial nephritis.     

亚热带松林中强酸性土壤自养和异养硝化作用的研究

The occurrence of nitrification in some acidic forest soils is still a subject of debate. Identification of main nitrification pathways in acidic forest soils is still largely unknown. Acidic yellow soil (Oxisol) samples were selected to test whether nitrification can occur or not in acidic subtropical pine forest ecosystems. Relative contributions of autotrophs and heterotrophs to nitrification were studied by adding selective nitrification inhibitor nitrapyrin. Soil NH₄⁺-N concentrations decreased, but NO₃^--N concentrations increased significantly for the no-nitrapyrin control during the first week of incubation, indicating that nitrification did occur in the acidic subtropical soil. The calculated net nitrification rate was 0.49 mg N kg^-1 d^-1 for the no-nitrapyrin control during the first week of incubation. Nitrapyrin amendment resulted in a significant reduction of NO₃^--N concentration. Autotrophic nitrification rate averaged 0.28 mg N kg^-1 d^-1 and the heterotrophic nitrification rate was 0.21 mg N kg^-1 d^-1 in the first week. Ammonia-oxidizing bacteria (AOB) abundance increased slightly during incubation, but nitrapyrin amendment significantly decreased AOB amoA gene copy numbers by about 80%. However, the ammonia-oxidizing archaea (AOA) abundance showed significant increases only in the last 2 weeks of incubation and it was also decreased by nitrapyrin amendment. Our results indicated that nitrification did occur in the present acidic subtropical pine forest soil, and autotrophic nitrification was the main nitrification pathway. Both AOA and AOB were the active biotic agents responsible for autotrophic nitrification in the acidic subtropical pine forest soil.     

Practical aspects of the estimation of the time of ovulation and of insemination in the bitch

The aims of this study were to assess the precision of the estimates of the time of ovulation derived by various methods, and to define the most appropriate methods for the determination of the optimal time for insemination of bitches with fresh semen (artificial insemination or natural mating), or with frozen-thawed semen. In 11 Labrador bitches, ovulation was estimated (plasma LH surge + 48 h) to occur 9 to 20 d after the start of the cycle, 0 to +4 d after the onset of positive postural reflexes (2 bitches showed no positive postural reflexes), -4 to +7 d after reaching a vaginal cytological eosinophilic index (EI) of 100%, over a range of 2.5 to 5.5 d based on plasma progesterone concentrations of 4 to 10 ng/ml, over a range of 2 to 3 or 4 d based on 2 indirect methods of estimating the time of the plasma LH surge from plasma progesterone concentrations. Assuming fertilisation occurs 2 to 3 d after ovulation, these findings indicate that for fresh semen (with an estimated lifespan of greater than 4 days) an appropriate procedure would be to inseminate/mate on the day after the onset of positive postural reflexes; then 3 days later. For bitches not showing positive postural reflexes, insemination should occur when the vaginal EI = 90% and then each 3 d until day 1 of dioestrus (D1). For frozen-thawed semen (with a lifespan of less than 24 h) insemination should occur 4 to 5 d after the plasma LH surge.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of nitrogen supply on competition between wheat and three annual weed species

Three pot experiments have investigated the effects of nitrogen (N) supply on interspecific competition between three weed species ( Phalaris minor Retz., Chenopodium album L, and Sinapis arvensis L.) and spring wheat ( Triticum aestivum L.) cv, Alexandria. The treatments tested included monocultures of each species and a mix-ture containing them in equal proportions that were combined factorially with two levels of N supply (20, 120 kg N ha^-1). Low N supply decreased net photosynthetic rate (P_n), leaf N percentage, plant dry weight and N uptake of both wheat and weed species and gram dry weight of wheat. The effects of low N on P_n and dry weight of weeds were greater than the effects on wheat. In most cases the decrease in P_n at low N was due to non-stomatal factors. The relative competitive abilities of wheat and weeds were influenced by N supply. At high N, S.arvensis was more competitive than wheat, whereas P. minor was less competitive than wheat. C. album was more competitive than wheat at both N levels. The rank order of competitive ability of the weed species was C. album > P. minor > S. arvensis . The effects of interspecific competition on P_n were smaller than the effects of N supply and were not associated with corresponding effects on leaf N percentage and plant dry weight of both wheat and weed species and grain dry weight of wheat.     

Dysautonomia in a six‐year‐old mule in the United States

Equine dysautonomia, also known as equine grass sickness (EGS), is a well documented disease in several countries. To the authors’ knowledge, EGS has not been reported previously in North America. This report describes EGS in a 6‐year‐old female mule in the USA. Failure initially to consider EGS resulted in a delayed diagnosis. EGS should be considered as a differential diagnosis and appropriate diagnostic tests performed in similar cases in North America.