Comparison of inhibition of polymerisation of mammalian tubulin and helminth ovicidal activity by benzimidazole carbamates

The correlation between the inhibition of hatching of Haemonchus contortus eggs and inhibition of mammalian tubulin polymerisation by benzimidazole carbamates has been investigated. The hatching process was observed to be independent of the biomass (eggs plus debris) over a 6-fold range and the early (E1-E3) stages of egg development, but was dependent on the concentration of co-solvent (DMSO) and time of incubation. Benzimidazole carbamates with strong inhibitory activity against mammalian tubulin were potent inhibitors of egg hatch, while non-inhibitors failed to prevent hatching. It is postulated that the primary mode of action of these drugs on nematode eggs is the inhibition of microtubule-dependent processes within the developing egg. The implications and limitations of this correlation are discussed.     

Clinical pathologic alterations in horses during a water deprivation test

A 72-hour water deprivation test was performed in 12 horses to determine clinical pathologic changes. Reference values for electrolyte (X) clearance, expressed as a percentage of creatinine clearance (CLCR; %CLCRX), were also determined. A comparison was made between urine concentration measurement techniques. Results of %CLCRX determination in 12 horses before water deprivation were 0.034 +/- 0.095 %CLCRNa, 42.4 +/- 9.8 %CLCRK, 0.352 +/- 0.190 %CLCRCl, and 0.710 +/- 0.250 %CLCRP. During water deprivation, there was individual variation for electrolyte clearances, but Na excretion increased significantly (P less than 0.01) at 24 and 48 hours. After 48 hours' water deprivation, %CLCRNa decreased significantly, but was still greater than the initial clearance. Plasma protein was a better indicator of water deprivation (dehydration) in the horse than was PCV. Electrolyte concentrations in serum and urine were determined. Little significant (P less than 0.01) change in acid-base values was noticed after 72 hours' water deprivation. Urine osmolality (as determined by osmometry) was compared with sp gr (determined by refractometry) in determining urine concentration. Initially, sp gr correlated well with urine osmolality determinations, but this correlation decreased after 48 hours.     

Type-I hypersensitivity as a component of eosinophilic myositis (muscular sarcocystosis) in cattle

Eight bovine hearts with lesions of eosinophilic myositis (EM) and 2 bovine hearts without EM lesions were collected at slaughter. Blood samples from these 10 hearts, and the heart of a newborn calf also were collected. Histologically, Sarcocystis cruzi was identified in the 8 hearts with EM lesions and the 2 hearts without EM lesions, but not in the heart of the newborn calf. Serum was harvested from the 10 blood samples and was used in homologous, modified, passive cutaneous anaphylaxis tests. Antigen was prepared from S cruzi bradyzoites isolated from the 2 hearts without EM lesions. Serum samples from the 8 cattle with EM lesions reacted positively to S cruzi antigen. When heat-inactivated IgE in serum (56 C for 4 hours) was used, all passive cutaneous anaphylaxis responses were considered negative. Using ELISA, serum IgE concentrations from the 10 cattle with and without EM lesions were 2.2 to 9 U/ml. As determined by radial immunodiffusion, IgM concentrations were 80 to 215 mg/dl. Immunoglobulin G concentrations were 420 to 2,050 mg/dl, but most were less than or equal to 1,700 mg/dl. Immunoglobulin A concentrations were 0 to 62 mg/dl; 1 steer with EM lesions had 0 mg/dl. Double-gel immunodiffusion confirmed the presence of Sarcocystis-specific precipitating antibodies. Sera from the 10 cattle with and without EM lesions formed at least 1 precipitin band.     

Rabies-like inclusions in dogs

Inclusion bodies, indistinguishable from rabies inclusion bodies (Negri bodies), were found in the brains of 8 nonrabid dogs. The inclusions were compared to Negri bodies present in neurons of rabies-positive animals and examined for the presence of rabies virus by a combination of immunoperoxidase staining (7 cases), fluorescent antibody (FA) staining (1 case), and transmission electron microscopy (4 cases). Positive immunoperoxidase staining for rabies was obtained in brain tissues from FA rabies-positive animals. All brain tissues from the 7 dogs stained by the immunoperoxidase method and the brain from the 1 dog stained by the FA method were negative for rabies. Rabies virus was not found in inclusion-containing neurons in the cases examined by transmission electron microscopy. These results emphasize the importance of FA testing and mouse inoculation for the diagnosis of rabies.     

Monorchidism in the horse

Six horses with monorchidism, identified at surgery for cryptorchidectomy, are reported. All six presented with a single scrotal testis. Following surgical removal of one testis, they were either hormonally, anatomically or behaviourally determined to be geldings. Three other horses reported in the literature are reviewed. Of these nine cases of monorchidism, eight were thought to be caused by testicular degeneration and one by testicular agenesis. The vaginal process was present in all of the former and absent in the latter. The left side was involved in five of these eight horses. In seven, the epididymis was absent and, in the remaining two, only the epididymal tail was present. The condition was thought to be congenital in the six horses in this series. A surgical approach to identify accurately monorchid horses is described.     

Effects of the Chernobyl accident on animal husbandry and production, from a Swedish perspective

About 20% of the Swedish land area was considerably contaminated by radionuclides released by the nuclear accident at Chernobyl, Ukraine, in April 1986. However, less than 10% of the arable land was contaminated. The heavy contamination was closely correlated with the amount of rain received during the first days of May 1986. Immediate restrictions on grazing limited the early uptake of contaminants in animal products. Changes in management of animals, especially sheep, goats, and reindeer in the contaminated areas have effectively reduced the transfer of radionuclides to human beings. One important factor was the possibility of obtaining uncontaminated feeds from unaffected parts of the country. The direct costs during the first 2 years after the accident were approximately +10 million for analyses and +90 million for compensation to farmers for condemned products (milk, mutton, and reindeer meat) and reimbursement for purchase of uncontaminated feeds from other parts of the country.