Haematological measurements as an aid to early diagnosis and prognosis of respiratory viral infections in thoroughbred horses.

In late November 1988 large numbers of thoroughbred horses in training in Hong Kong developed a transient pyrexia with, in some cases, the clinical signs of viral respiratory disease. Serial blood samples for haematological examination were taken from 10 of the horses which were stabled in six different blocks. They had developed a high temperature within three days of each other and subsequently seroconverted to equine herpes virus 1 (EHV1). The absolute monocyte count was more than 0.5 x 10(9)/litre in all 10 within the first five days, and nine of them had a high neutrophil/lymphocyte ratio on the first day, which then decreased and reversed within four or five days. Five of the horses had a high plasma viscosity, and a large difference between the viscosity of plasma and serum which in three of them returned to normal within 10 days. In the two and a half months after the initial infection six of nine of the horses, including the five which had a large difference between the viscosity of plasma and serum, developed visible mucopus by endoscopic examination. These haematological and endoscopic changes can be used to detect horses in the acute stages of EHV1 infection and monitor the progress of the disease, before it can be confirmed by isolation of the virus and, or, serology.

Haematological changes in two thoroughbred horses in training with confirmed equine herpesvirus 1 infections.

An outbreak of respiratory disease among thoroughbred horses in training in Hong Kong was caused by equine herpesvirus 1 (EHV-1) subtype 1 (abortion strain). Two of the horses affected by EHV-1 were serially blood sampled over a period of several weeks and their haematological values measured. There was an increase in monocyte count in the first few days which steadily decreased in one horse, but the other had a second monocyte peak after a period of exercise, thus demonstrating the importance of not working animals in the early stages of the disease.

The influence of anaesthesia on plasma spermidine concentration and renal excretion in rats.

Anaesthesia with ether or a mixture of fentanyl and fluanisone diminished the clearance of infused spermidine from plasma in WAG/Rij rats considerably. The renal excretion of infused spermidine in unanaesthetized animals was only very small. The diminished plasma clearance of infused spermidine in anaesthetized animals therefore cannot be explained by loss of renal excretion.

The fate of infused spermidine in the plasma of rats.

An elevation of the plasma spermidine concentration might indicate whether administration of a cytostatic drug harms tumour cells. Such elevations, however, are only small. By infusing various amounts of spermidine into the circulation of rats, spermidine plasma elevations were evoked artificially. During 2.5 h infusion and 1.5 h after infusion spermidine plasma concentrations were measured. It appeared that total amounts of 0.031 and 0.4 mg did not give an appreciable elevation of plasma spermidine concentrations above basic levels. Infusion of 1.0 mg gave rise to an elevation but already showed a trend towards normal levels during the infusion. There is evidence for a first-pass lung effect for spermidine. Blocking of monoamine and diamine oxidase enzymes resulted in a further elevation of spermidine concentrations above basic levels. Which of the two enzymes is the more important for spermidine catabolism could not be determined.