The activity of diagnostic enzymes and the concentration of lipids in the blood vessels of cattle

Blood vessel walls are shown to contain creatine phosphokinase, lactate dehydrogenase, gamma glutamyl transpeptidase and aspartate transaminase activity. The activity of these enzymes in the serum may be enhanced by leakage from damaged blood vessels.The activity of the enzymes alanine transaminase and alkaline phosphatase as well as the content of triglycerides, cholesterol and lipoproteins are very low in the vascular tissue and are unlikely to be of diagnostic value in vascular tissue injury.     

The relationship between the Physicochemical properties of pyrethroid insecticides and their speed of neurotoxic action

The rate of onset of pyrethroid-induced depolarisations of the nerve cell membrane in isolated ganglia of the leech Hirudo medicinalis was measured using intracellular recordings. The speed of neurotoxicity of a series of substituted benzyl (1RS)-trans-cyclopropane-1-carboxylates was related to the size of the groups at C3 and C4 of the benzyl ring, the ability of the ring substituents to donate electrons, and the nature of the substituents at the two terminal positions of the vinyl group subtended by the cyclopropane ring. The speed of action was also related to the electronic environment of the protons subtended by the geminal methyl group held trans to the carboxyl group. Compounds, the partition properties of which were sensitive to interactions between the pyrethroid and solvent molecules, tended to act rapidly. There was no simple relationship between the speed of neurotoxic action in isolated leech ganglia and the knockdown potency to mustard beetles.     

Differentiation of sexual behavior in cattle, sheep and swine

Gonadal steroid hormones influence an animal's sexual behavior through two primary means. During development they affect differentiation of the brain (primarily in males), and after puberty, circulating concentrations of steroids influence expression of sexual behaviors. In mammals, sexual behaviors of females are regarded as inherent (independent of steroids secreted by the developing ovary). Males, on the other hand, must undergo active differentiation that is brought about by actions of testicular steroids on the brain during discrete sensitive periods of early development. Sexual differentiation in mammals is referred to as processes of defeminization and masculinization. Defeminization is loss of behavioral traits inherent to females and occurs prenatally in sheep but postnatally in swine. Comparative data are lacking for cattle, but preliminary evidence indicates prenatal defeminization of sexual behaviors. Masculinization is acquisition of behavioral traits characteristic of males. Adult females of all three species show mounting behavior after prolonged treatment with testosterone, and in cattle and swine, there is, as yet, no strong evidence that males undergo masculinization of sexual behaviors. In sheep, limited observations are suggestive of two sensitive periods for masculinization; one prenatally and one postnatally. The earlier concept that differentiation of sexual behaviors in mammals occurs prenatally in species with a long gestation and postnatally in species with a short gestation must now be modified in view of recent findings in swine, in which defeminization occurs postnatally. Further studies will likely identify additional species differences with respect to differentiation of sexual behaviors.     

Further studies on the diagnostic value of gamma-glutamyl transpeptidase and 5'-nucleotidase in cattle, sheep and horses

The distribution of 5'-nucleotidase (5'-NT) and gamma-glutamyl transpeptidase (gamma-GT) is similar in the tissues of the sheep, calf and horse, except that there is relatively less gamma-GT in calf liver than in the liver of the other two species. The liver lesion produced by the oral administration of chloroform is similar in the three species and is accompanied by the release of 5'-NT into the plasma of the sheep and calf but not of the horse. Conversely, gamma-GT is released into plasma of the horse but not of the sheep or calf. This difference is not related to the tissue distribution of the two enzymes. The kidney lesion in sheep produced by the intravenous administration of mercuric chloride is accompanied by a reduction in the rate of excretion of an injected dose of inulin and by an increase in the concentration of urea in plasma and in the activity of gamma-GT in plasma and urine. There was no increase in 5'-NT activity in plasma or urine.     

Viability of split-thickness skin grafts attached with fibrin glue.

Full-thickness, circular, cutaneous wounds (4 cm diameter) were created on metacarpi and metatarsi of 5 horses. On day 6, all 4 wounds on each horse received a stored autogenous split-thickness sheet graft. Grafts were obtained from the horse's ventrolateral thorax with a pneumatic dermatome at the time the cutaneous wounds were created. Grafts were coapted to the granulation bed of 2 wounds of each horse with fibrin glue. Grafts were coapted to the cutaneous margin of all 4 wounds of each horse with cyanoacrylate glue. Bandages were changed daily until the study ended at 14 d. When the bandages were changed, ointment containing neomycin, polymyxin B, and bacitracin was applied to all wounds. The viable area of graft was measured on post-grafting d 14 and calculated with a micro-processor. Split-thickness sheet-grafts attached to granulation beds on the metacarpi and metatarsi with fibrin glue had no greater survival than did grafts attached without fibrin glue (P > 0.05).     

Specific effects of blood plasma from beef cows fed pine needles during late pregnancy on increasing tone of caruncular arteries in vitro.

Consumption of Ponderosa pine needles by cows during late pregnancy results in the premature delivery of viable calves. Previous observations made at necropsy suggested that vascular insufficiency in the caruncular bed was associated with this induced parturition. The present studies used the perfused caruncular arterial bed of an isolated bovine placentome to determine whether blood plasma collected from cows fed pine needles contained a vasoactive factor(s). Changes in caruncular arterial tone (i.e., long-term changes in vessel diameter) and phasic contractility (i.e., transient reductions in vessel diameter) were evaluated. Tone was quantified as the pressure exerted against a constant intraluminal flow and as the force of contraction during K(+)-stimulated depolarization of membranes. Phenylephrine, an alpha 1-adrenergic agonist, was used to stimulate a phasic contractile response. Jugular blood was collected from beef cows fed pine needles (n = 4) or a control diet (n = 4), during the last 3 d of gestation, and plasma was used for two studies. In Study 1, placentomes were perfused with decreasing dilutions (1:150 to 1:40) of plasma pooled over the last 3 d of pregnancy from cows fed pine needle or control diets. Caruncular arterial perfusion pressures and responses to K+ progressively increased (P less than .05) with decreasing dilutions of plasma from cows fed pine needles, and responses to phenylephrine remained constant. Caruncular arterial perfusion pressures and responses to K+ and phenylephrine remained constant during perfusion of plasma from cows fed the control diet. In Study 2, the changes in vasoactivity of plasma (1:60 dilution) from cows fed pine needles was evaluated during the last 3 d of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Idiopathic hyperchylomicronaemia in miniature schnauzers

Several authors have reported the presence of fasting hyperlipidaemia in adult miniature schnauzers presented with either paroxysmal abdominal pain, vomiting or diarrhoea. Acute pancreatitis is commonly confirmed. There appears to be no sex predilection for the condition although the majority of affected dogs are middle aged and older. Lipid profiles of affected dogs reveal extreme elevations of fasting serum triglyceride (TG) concentrations ranging from 5·5 mmol/litre to over 90 mmol/litre; the hyperlipidaemia is almost exclusively attributed to chylomicron excess. To date, the reviewer's studies have not shown a correlation between TG levels and severity of signs. However, miniature schnauzers with fasting TG levels greater than 5·5 mmol/litre are considered to be at significant risk and should be further evaluated as candidates for dietary intervention.