Neospora caninum in crows from Israel.

A cross-sectional Neospora caninum seroprevalence study was performed on free ranging crows (Corvus cornix, Corvus monedula and Corvus splendens) from Israel in order to assess their exposure to this pathogen and evaluate their role as potential hosts or as sentinels of infection. Using the modified agglutination test (MAT) with a cutoff titer of 1:100, 30 out of 183 crows (16.4%) were found to be N. caninum seropositive. Positive results were validated and confirmed by the indirect fluorescent antibody test (IFAT). There was 100% agreement between tests when cut-off titers of 1:50 and 1:100 were applied for the IFAT and MAT, respectively. PCR analysis of brain extracts from all crows resulted in the detection of N. caninum DNA for the first time in crows belonging to two species, C. cornix and C. monedula. The high N. caninum seroprevalence in crows suggests that widespread exposure to infection with N. caninum exists especially in central and northern Israel and that crows may act as suitable markers for disease prevalence in the areas in which they are found.

Dopamine-induced apoptosis in human neuronal cells: inhibition by nucleic acids antisense to the dopamine transporter.

Human neuroblastoma NMB cells take up [3H]dopamine in a selective manner indicating that dopamine transporters are responsible for this uptake. These cells were therefore used as a model to study dopamine neurotoxicity, and to elucidate the role of dopamine transporters in controlling cell death. Treatment with 0.05 0.4 mM dopamine changed cells' morphology within 4 h, accompanied by retraction of processes, shrinkage, apoptosis-like atrophy, accumulation of apoptotic particles, DNA fragmentation and cell death. Cycloheximide inhibited dopamine's effect suggesting that induction of apoptosis by dopamine was dependent upon protein synthesis. Dopamine cytotoxicity, monitored morphologically by flow cytometric analysis, and by lactate dehydrogenase released, was blocked by cocaine but not by the noradrenaline and serotonin uptake blockers desimipramine and imipramine, respectively. Attempting to inhibit dopamine transport and toxicity in a drug-free and highly selective way, three 18-mer dopamine transporter antisense phosphorothioate oligonucleotides (numbers 1, 2 and 3) and a new plasmid vector expressing the entire rat dopamine transporter complementary DNA in the antisense orientation were prepared and tested. Antisense phosphorothioate oligonucleotide 3 inhibited [3H]dopamine uptake in a time- and dose-dependent manner. Likewise, transient transfection of NMB cells with the plasmid expressing dopamine transporter complementary DNA in the antisense orientation partially blocked [3H]dopamine uptake. Antisense phosphorothioate oligonucleotide 3 also decreased, dose-dependently, the toxic effect of dopamine and 6-hydroxydopamine. Western blot analysis with newly prepared anti-human dopamine transporter antibodies showed that antisense phosphorothioate oligonucleotide 3 decreased the transporter protein level. These studies contribute to better understand the mechanism of dopamine-induced apoptosis and neurotoxicity.