Objective—To determine whether thalidomide
inhibits the growth of primary and pulmonary
metastatic canine osteosarcoma in mice after xenotransplantation.
Animals—Athymic nude mice.
Procedure—Canine osteosarcoma cells were injected
SC in 50 mice. Mice were randomly placed into
the following groups: control group (n = 13; DMSO
[drug vehicle] alone [0.1 mL/d, IP]); low-dose group
(12; thalidomide [100 mg/kg, IP]), mid-dose group (13;
thalidomide [200 mg/kg, IP]); and high-dose group
(12; thalidomide [400 mg/kg, IP]). Starting on day 8,
treatments were administered daily and tumor measurements
were performed for 20 days. On day 28,
mice were euthanatized and primary tumors were
weighed. Lungs were examined histologically to
determine the number of mice with metastasis and
tumor emboli. Mean area of the pulmonary
micrometastatic foci was determined for mice from
Results—Primary tumor size and weight were not
significantly different among groups. The number of
mice in the mid-dose (200 mg/kg) and high-dose (400
mg/kg) groups with micrometastasis was significantly
less than the number of control group mice; however,
the number of mice with tumor emboli was not
affected by thalidomide treatment. Size of
micrometastasis lesions was not affected by thalidomide
Conclusions and Clinical Relevance—Mean area of
micrometastases was not affected by treatment;
however, growth of micrometastases had not yet
reached an angiogenesis-dependent size. Although
thalidomide did not affect growth of primary tumors in
mice after xenotransplantation of canine osteosarcoma
cells, our findings indicate that thalidomide may
interfere with the ability of embolic tumor cells to
complete the metastatic process within the lungs.
( Am J Vet Res 2004;65:659–664)
Objective—To compare neutralizing antibody response
between horses vaccinated against West Nile virus
(WNV) and horses that survived naturally occurring
Design—Cross-sectional observational study.
Animals—187 horses vaccinated with a killed WNV vaccine
and 37 horses with confirmed clinical WNV infection.
Procedure—Serum was collected from vaccinated
horses prior to and 4 to 6 weeks after completion of
an initial vaccination series (2 doses) and 5 to 7
months later. Serum was collected from affected
horses 4 to 6 weeks after laboratory diagnosis of
infection and 5 to 7 months after the first sample was
obtained. The IgM capture ELISA, plaque reduction
neutralization test (PRNT), and microtiter virus neutralization
test were used.
Results—All affected horses had PRNT titers ≥ 1:100 at
4 to 6 weeks after onset of disease, and 90% (18/20)
maintained this titer for 5 to 7 months. After the second
vaccination, 67% of vaccinated horses had PRNT titers
≥ 1:100 and 14% had titers < 1:10. Five to 7 months
later, 33% (28/84) of vaccinated horses had PRNT titers
≥ 1:100, whereas 29% (24/84) had titers < 1:10.
Vaccinated and clinically affected horses' end point
titers had decreased by 5 to 7 months after vaccination.
Conclusions and Clinical Relevance—A portion of
horses vaccinated against WNV may respond poorly.
Vaccination every 6 months may be indicated in certain
horses and in areas of high vector activity. Other
preventative methods such as mosquito control are
warranted to prevent WNV infection in horses. (J Am
Vet Med Assoc 2005;226:240–245)