Protective immune response of chickens to oral vaccination with thermostable live Fowlpox virus vaccine (strain TPV-1) coated on oiled rice.

The objective of the present study was to develop and evaluate a local vaccine (strain TPV-1) against Fowl pox (FP) in chickens. Two separate groups of chickens were vaccinated with FP vaccine through oral (coated on oiled rice) and wing web stab routes, respectively. The results showed that the haemagglutination-inhibition (HI) antibody titres in both vaccinated groups were comparable and significantly higher (P < 0.05) than the control chickens. It was further revealed that 14 days after vaccination HI GMT of > or =2 log(2) was recorded in chickens vaccinated by oral and wing web stab routes whereas 35 days after vaccination the HI antibody titres reached 5.6 log(2) and 6.3 log(2), respectively. Moreover, in both groups the birds showed 100% protection against challenge virus at 35 days after vaccination. The findings from the present study have shown that oral route is equally effective as wing web stab route for vaccination of chickens against FP. However, the oral route can be used in mass vaccination of birds thus avoid catching individual birds for vaccination. It was noteworthy that strain TPV-1 virus could be propagated by a simple allantoic cavity inoculation and harvesting of allantoic fluid where it survived exposure at 57 degrees C for 2 hours. If the oral vaccination technique is optimized it may be used in controlling FP in scavenging and feral chickens. In conclusion, the present study has shown that FP vaccine (strain TPV-1) was safe, thermostable, immunogenic and efficacious in vaccinated chickens.

Platelet-activating factor enhanced the pressor response of endothelin-1.

Both endothelin-1 (ET-1) and platelet-activating factor (PAF) have been suggested to play a role in the regulation of the cardiovascular system. In view of the limited data regarding the interaction between ET-1 and PAF, the hemodynamic effects of ET-1 and PAF, either alone or in combination, were investigated in the current study. Anesthetized male Sprague Dawley rats received bolus intravenous injections of ET-1 (1 and 2 nmol/kg) and/or PAF (0.075, 0.15 and 0.3 nmol/kg). In some experiments, the ET receptor antagonist, FR-139317 (2.5 or 5 mg/kg), were injected 5 min before the administration of ET-1 or PAF. ET-1 caused a biphasic response consisting of an initial depressor followed by a delayed but sustained pressor response. Injection of PAF to anesthetized rats resulted only in a decrease in arterial blood pressure. Interestingly, the pressor effect of ET-1 was significantly enhanced in the concomitant presence of PAF. Pretreatment with FR-139317 inhibited the magnitude of ET-1-induced hypertension and increased the duration of the depressor action of ET-1. The time-course of PAF-induced decrease of arterial blood pressure was also prolonged in rats pretreated with FR-139317. These data therefore suggested that ET receptors were activated, either directly or indirectly, by PAF, possibly to facilitate the return of blood pressure to resting level following a depressor response. Thus the activation of ET receptors by PAF might result in the enhancement of the pressor response of ET-1 observed in the current study.