Locomotion and chemotaxis of mononuclear phagocytes

The capacity for locomotion and for chemotaxis is probably very different in monocytes and macrophages from different sources. Numerous techniques have been established for studying the locomotion of these cells. Many of the factors are sparsely documented and the reports are scattered among various cell types. Heterogeneity of locomotion and chemotactic responsiveness is evident when established macrophage lines and mouse peritoneal macrophage are studied. The effects of mononuclear phagocytes and their released products on the locomotion of other cell types are reviewed.     

Experimental evidence that tryptamine alkaloids do not cause Phalaris aquatica sudden death syndrome in sheep

The acute toxicity for sheep of 3 alkaloids that occur in Phalaris acquatica was examined by intravenous and oral administration. The lowest tested dose rates that produced clinically observed signs were, for 5-methoxy dimethyltryptamine, 0.1 mg/kg body weight intravenously and 40 mg/kg orally; for gramine, 10 mg/kg intravenously and 500 mg/kg orally; and for hordenine, 20 mg/kg intravenously and 800 mg/kg orally. All induced the clinical signs observed in the nervous form of phalaris toxicity, but none induced the cardiac, sudden death, syndrome.     

Gibberellin influence on membrane disruption by thiocarbamate herbicides

Vernolate (0, 8, 16, 31, 62, 125.0, or 250.0 ppbw) incorporated into sand inhibited the growth of wheat (Triticum aestivum L. cv Holley) at 125.0 ppbw. These growth inhibition and morphological responses were virtually identical to wheat response to EPTC at 125 ppbw. ¹⁴C from vernolate (carbonyl labeled) (125.0 ppbw) was absorbed into wheat seedlings at approximately 1.8 μM on the presumption that the ¹⁴C present was [¹⁴C]vernolate. Since the response of wheat to the thiocarbamate herbicides resembles a gibberellic acid (GA) deficiency and cell enlargement requires the presence of functional plasmalemmas and tonoplasts, the question of membrane disruption by excessive concentrations of thiocarbamate herbicides and potential reversal thereof by GA₃ was studied by measuring the efflux of K⁺, Na⁺, and Mg²⁺. GA₃ (0.003 μM) stimulated lettuce leaf disc growth in diameter and fresh weight. This GA-stimulated increase in size and weight was reversed by 1 mM EPTC. Betacyanin efflux from beet leaf tonoplasts was increased by 1 mM EPTC and this efflux was not reversed by exogenous GA₃ (0.3 μM). This influence by supraoptimal EPTC concentrations was shown to be via membrane disruption, which obviated any possible GA influence by eliminating the functionality of the membranes requisite to the development of a GA response. It is concluded that viable mode-of-action studies must measure physiological responses consistent with the symptomology of herbicide responses normally observed with each herbicide at field concentrations.     

The pathogenic role of pulmonary intravascular macrophages in acute African swine fever

Recent studies of pulmonary intravascular macrophages have led to the re-examination of the mechanisms giving rise to alveolar oedema. A highly virulent isolate of African swine fever virus was replicated in pulmonary intravascular macrophages, interstitial and alveolar macrophages, fibroblasts and neutrophils. The alveolar oedema — characteristic of acute forms of African swine fever — and the vascular changes observed, which consisted of the formation of fibrin microthrombi in septal capillaries and the vacuolisation of endothelial cells, may have been due, however, to the activation of pulmonary intravascular macrophages, and not to the cytopathic effect subsequent to the replication of the African swine fever virus. Furthermore, it was observed that virus replication in cells not belonging to the mononuclear phagocyte system — such as fibroblasts and neutrophils — occurred earlier than in cells belonging to that system.     

Vaccine efficacy for reducing turbinate atrophy and improving growth rate in piggeries with endemic atrophic rhinitis

Two vaccines, based on formalin-killed whole cells of toxigenic Pasteurella multocida type D and Bordetella bronchiseptica combined with a partially toxoided cell extract of P multocida, were prepared with Freund's incomplete adjuvant (vaccine 1) or by alum precipitation (vaccine 2). Each was tested for safety and efficacy in reducing the severity of nasal turbinate atrophy and improving the growth rate of pigs in three Western Australian commercial piggeries with endemic atrophic rhinitis. In safety experiments with vaccine 1, no adverse clinical effects were observed in vaccinated sows or their progeny. Piglets receiving vaccine 2 showed no injection site abnormalities, pyrexia or turbinate atrophy. In field trials, vaccine 1 significantly reduced the prevalence of moderate to severe nasal turbinate atrophy (Done score 3 to 5) when used in two piggeries (A and B). Progeny from vaccinated sows in piggery B also grew significantly faster than controls. When vaccine 2 was used in piggery A at a later date and in another piggery (C), growth rate was not improved in either piggery and the prevalence of moderate to severe turbinate atrophy was reduced only in piggery C.     

Prothrombin time and activated partial thromboplastin time using a point‐of‐care analyser (Abaxis VSpro®) in Bennett's wallabies (Macropus rufogriseus)

There are few reports of coagulation times in marsupial species. Blood samples collected from 14 Bennett's wallabies (Macropus rufogriseus) under anaesthesia during routine health assessments were analysed for prothrombin time (PT) and activated partial thromboplastin time (aPTT) using a point‐of‐care analyser (POC) (Abaxis VSPro®). The wallabies had an aPTT mean of 78.09 s and median of 78.1 s. The PT for all wallabies was greater than 35 s, exceeding the longest time measured on the POC. Although PT was significantly longer, aPTT was similar to the manufacturer's domestic canine reference range.     

Enriched Topographic Microsites for Improved Native Grass and Forb Establishment in Reclamation

Low seed germination and seedling establishment are the greatest challenges for revegetation success. Topographic microsites are known to enhance seed germination and seedling establishment due to their unique soil properties and provision of shelter from elements and herbivores; soil amendments can supply organic matter and nutrients for plant establishment and growth when limited. We investigated the effect of three topographic microsites and six soil amendments and their additive effects on three disturbed grasslands in central and southern Alberta, Canada. Treatments were topographic microsites of mounds, pits, and flats, with and without amendments (erosion control blanket, hay, straw, manure, hydrogel, control) and were seeded with four native grasses and three native forb species. Seedling emergence and survival and soil temperature and water content were assessed over two seasons and plant cover over three seasons. The effect of microsites and amendments was not additive. The addition of erosion control blanket, hay, and straw to flat sites was just as productive as on topographic microsites. These amendments increased grass and forb emergence and buffered soil temperature. Mounds increased first year forb emergence and reduced over winter survival rates for grasses and forbs. Pits were not beneficial for revegetation. The effect of topographic microsites and amendments was influenced by site conditions.