BACTERIAL ENDOCARDITIS WITH THROMBUS FORMATION AND ABSCESSATION IN A HORSE

A 2.5 year old Appaloosa stallion with progressive weight loss and a heart murmur was diagnosed as having vegetative endocarditis of the right atrioventricular valves with a mass in the right atrium. The ultrasonographic appearance of the lesion was characterized by extreme reverberation. On postmortem examination, a 9 cm diameter thrombus was found within the right atrium and auricle, occupying approximately 80% of the chamber volume. Additionally, a lenticular abscess extended throughout the parietal cusp of the right atrioventricular valve. Histologic examination revealed that the lesions were septic with numerous gram positive cocci in short chains, suggestive of Streptococcus equi , and gram negative rods.     

Thrombocyte aggregation in the cat

Platelet aggregation in healthy and sick cats after adding various aggregating agents is described. Feline platelets aggregate irreversibly in response to 0.15-1.0 micrograms/ml collagen, 1 microM ADP, 0.3 IU/ml test-thrombin and 0.71 NIH/ml Topostasin. Epinephrine, ristocetin and kaolin failed to cause aggregation. The aggregation function was decreased in a cat with liver damage and icterus; in 2 cats with uremia platelet aggregation was normal. Acetylsalicylic acid (ASA) (10 mg/kg iv) inhibits platelet aggregation in the presence of collagen in low concentrations; high concentrations of collagen succeeded in inducing platelet aggregation.     

Effects of α2-adrenergic drugs on blood platelets in sheep

Xylazine (0.2 mg/kg, iv) alone or preceded by atipame-zole (0.125 μg/kg, iv) or by aspirin (10 μg/kg, iv) was administered to 18 sheep. Medetomidine (60 μg/kg, iv) was also administered to 12 sheep. Xylazine, but not medetomidine, significantly reduced the number of platelets. Both atipamezole and aspirin prevented this reduction. It was concluded that α₂-agonists would seem to produce platelet aggregation that may contribute to the development of the respiratory changes that follow the administration of α₂-agonists in sheep, but probably not always to a degree that could result in a significant decrease in the number of circulating platelets.     

Measurement of nitrate leaching losses from arable plots under different nitrogen input regimes

Abstract. Leaching losses of nitrate-nitrogen were measured from a set of eight hydrologically isolated plots on a clay loam soil over the period from September 1987 to February 1990. Variable drainflow recovery from the plots hampered accurate estimation of nitrate loading, but results suggest that, when inorganic nitrogen fertilizer is applied up to the recommended amount, there is little influence of the amount applied on the amount leached. We did, however, observe the following effects on nitrate leaching: leguminous green manure incorporated in autumn increased leaching of nitrate-nitrogen by 10–15 kg per hectare during the winter; autumn cultivation caused some increase in leaching compared with no cultivation in one year; some systematic variations in nitrate leaching occurred between years and between plots, but were unrelated to treatments.
From the results we conclude that green manuring does not provide sufficient nitrogen for organically grown crops on this soil but contributes significantly to nitrate leaching, and that growing spring cereals, with the land remaining in stubble as long as possible in autumn, may be the best strategy to minimize nitrate leaching.     

THE INSENSITIVITY OF 99mTc PERTECHNETATE FOR DETECTING METASTASES OF A FUNCTIONAL THYROID CARCINOMA IN A DOG

This report describes the use of ^99mtechnetium pertechnetate (^99mTcO₄⁻) and ¹³¹[for imaging of a metastatic thyroid carcinoma in a dog. The ¹³¹] imaging showed metastatic lesions undetected by the ^99mTcO₄⁻ imaging on 2 separate occasions. The possible mechanisms for the discrepancies between ¹³¹I and ^99mTcO₄⁻ imaging of thyroid carcinomas are discussed. The use of ¹³¹I for the imaging of functional thyroid carcinomas in the dog is recommended.     

Purification and characterization of hepatic triacylglycerol lipase isolated from rainbow trout,Oncorhynchus mykiss

Trialcylglycerol (TG) lipase was isolated and partially purified from rainbow trout liver. Triacylglycerol lipase activity was assayed by measuring¹⁴C-oleic acid release from¹⁴C-triolein.¹⁴C-oleic acid release was linear for up to two hours. Optimal activity occurred at pH 7.0 and 15°C. Most of the lipase activity was recovered in the cytosolic fraction. A 27,000-fold purification was achieved after Sepharose (Bio-gel A 0.5 M, 200–400 mesh) chromatography of a resuspended 20% ammonium sulfate fraction. The molecular weight of the trout hepatic lipase as determined by size-exclusion chromatography and by SDS-polyacrylamide gel electrophoresis was 40–43 kD. Lipase-mediated hydrolysis of TG resulted in the production of diacylglycerols, monoacylglycerols, and fatty acids. Kinetic analysis indicated that V_max=0.016 nmol/h/mg protein and that K_m=0.28 mM triolein. Lipolytic activity was enhanced in the presence of cAMP/ATP-Mg²⁺. These results suggest that the liver of trout possesses a neutral TG lipase that is responsible for mobilizing stored TG and is catalytically activated by phosphorylation.A part of this work was presented at the Annual Meeting of the American Society of Zoologists, December 26–30, 1990, San Antonio, TX.     

Influence of Low Light Irradiance on Grain Filling in Rice (Oryza saliva L.) cultivars

Time course of grain filling pattern in two rice (Oryza sativa L.) cultivars, grown under normal and low light intensities, was studied. The number of spikelets, partially filled grains and high density grains were monitored at a 5 day interval during grain filling period from uniform panicles tagged at anthesis. The low light tolerant cultivar Swarnaprabha had more high density grains and less partially filled grains throughout the grain filling period and at harvest compared to cultivar Ratna under both normal and low light intensities. Further, the opening of spikelets in two flushes in Swarnaprabha seemed to result in a more efficient resource allocation and hence better yield as compared to Ratna, in which the opening of spikelets was in a single flush on day 10.     

Metal toxicosis in horses.

The ubiquity and stability of metals in the environment make them unique as a pollutant or an essential dietary component. Metals are neither created nor destroyed by chemical processes but are redistributed in the environment. In combination with other elements, metal compounds and alloys are essential materials of the contemporary world. Inappropriate use or distribution in the environment leads to adverse health effects on all biologic systems, including horses. Gastrointestinal upset is a common feature of acute toxicosis with metals in general. Among the metals discussed, arsenic and inorganic mercury have a propensity to do severe damage to the gut. Deposition of cadmium on forage is the source most likely to intoxicate horses. This subchronic to chronic problem in horses is manifest as disease of the musculoskeletal system and kidneys. Iron-containing hematinics are widely used in racetrack horses and occasionally result in hepatopathy when excessive doses are administered. Lead continues to be recognized as the most significant environmental metal pollutant. Poisoning is encountered routinely in humans and animals. Of the animal species of veterinary concern, lead-poisoned horses are not a frequent encounter. Lead-intoxicated horses show signs of peripheral neuropathy (laryngeal hemiplegia), intermittent colic, and mild anemia. Acute mercury poisoning sometimes occurs from the common use of mercury-containing blistering agents, with most clinical findings related to acute renal failure. Chronic excessive intake of zinc by horses is uncommon but devastating in rapidly growing foals. The mechanism of chronic zinc toxicosis is coupled to the induced copper deficiency. The condition is a disease of cartilage in the articular and growth physes.     

Surgical treatment of lameness.

Digital diseases are commonly seen in cattle. Cattle affected by digital disorders do not always respond to conservative therapy and require surgery. Surgical procedures for the common digital disorders are described, with emphasis on the different approaches to the distal interphalangeal joint.