Parainfluenza-3 virus: difference in capacity of neuraminidase-weak and strong strains to infect young calves and to elicit cellular immune response.

Calves less than four weeks old could not be infected with a neuraminidase-weak strain of parainfluenza-3 virus (Pi3) but were successfully infected with either of two neuraminidase-strong strains. The criteria for infection were virus excretion, cell-mediated and antibody-mediated immune responses. In the lymphocyte stimulation test, calves infected with the neuraminidase-strong Pi3 strain Tüb-E6 responded more strongly to antigen prepared from this strain than to antigen from the heterologous Pi3 strain Um-23. The non-immunoglobulin haemagglutination inhibition activity of the liquid phase of nasal secretions of newborn calves decreased after treatment with Vibrio cholerae neuraminidase. For virus-bound neuraminidase the liquid phase from newborn calves was a richer substrate than the liquid phase from older animals.     

Perivascular wall tumour presenting as pastern mass in a Standardbred gelding

A 2-year-old Standardbred gelding was referred for a mass on the palmaromedial right front pastern which was accompanied by progressively worsening lameness. The mass was firm to palpation and covered by normal skin. Ultrasonographically, a smooth encapsulated mass was present, medial to the flexor tendons and palmar to the neurovascular bundle. Because of a poor prognosis for future athletic performance without surgical or chemotherapeutic intervention and economic constraints preventing further diagnostics and treatment, the horse was euthanised. Post-mortem magnetic resonance imaging, histopathology and immunohistochemistry revealed the mass to be a perivascular wall tumour, the first record of such a neoplasia in the horse.     

Nonabsorbable dietary fat enhances disposal of 2,2',4,4'-tetrabromodiphenyl ether in rats through interruption of enterohepatic circulation

Polybrominated diphenyl ethers are lipophilic persistent organic pollutants (POPs), which accumulate in the environment, leading to human exposure. The compounds exert a negative impact on human health. Strategies to prevent or diminish their accumulation in humans are required. We investigated in rats whether the disposal rate of 14C-labeled tetrabromodiphenyl ether (BDE-47) could be enhanced by increasing fecal fat excretion through dietary treatment with nonabsorbable fat (sucrose polyester, SPE). As compared to control rats, SPE treatment increased fecal excretion rates of fat (+188%, p < 0.05) and 14C-BDE-47 (+291%, p < 0.05). On the basis of biliary secretion and fecal excretion rates of 14C-BDE-47, SPE effectively inhibited the enterohepatic circulation of 14C-BDE-47. In conclusion, dietary supplementation of nonabsorbable fat can enhance excretion of hydrophobic POPs by interruption of their enterohepatic circulation. Our data indicate that this strategy could decrease concentrations of hydrophobic POPs in the human body and thereby their impact on human health.     

CD46 in meningococcal disease

The human-specific bacterial pathogen Neisseria meningitidis is a major cause of sepsis and/or meningitis. The pili of N. meningitidis interact with CD46, a human cell-surface protein involved in regulation of complement activation. Transgenic mice expressing human CD46 were susceptible to meningococcal disease, because bacteria crossed the blood-brain barrier in these mice. Development of disease was more efficient with piliated bacteria after intranasal, but not intraperitoneal, challenge of CD46 transgenic mice, suggesting that human CD46 facilitates pilus-dependent interactions at the epithelial mucosa. Hence, the human CD46 transgenic mice model is a potentially useful tool for studying pathogenesis and for vaccine development against meningococcal disease.