Immunization of pigs with a purified Shiga-like toxin II variant toxoid.

Passive transfer of neutralizing antibodies and active immunization with a toxoid of purified Shiga-like toxin II variant (SLT-IIv, edema disease toxin) were used to protect pigs against challenge with SLT-IIv. Six 6-week-old pigs were passively immunized by intraperitoneal administration of an immunoglobulin preparation from porcine antiserum against purified SLT-IIv. Six 6-week-old pigs and twelve 2-week-old pigs were actively immunized by two intramuscular injections of 25 micrograms of SLT-IIv toxoid given 2 weeks apart. The 24 immunized pigs and an equal number of age-matched unimmunized control pigs were all challenged by intravenous injection of purified SLT-IIv (6 ng/kg body weight). The six passively immunized pigs acquired neutralizing SLT-IIv antibody titers of 1280 or 2560 and the 18 actively immunized pigs mounted a serum immune response with toxin neutralizing titers ranging from 128 to 10,240. All 24 immunized pigs survived the challenge but nine pigs with the lowest titers showed mild clinical signs of edema disease. All 24 control pigs died within 30 hours of challenge.     

The role of conserved forages in the nutrition of the dairy cow

Forages are universally popular ingredients in dairy rations because of (1) their agronomic properties, (2) their economy as sources of energy and essential nutrients, and (3) their physiological role in digestion. The contribution that forages make in support of milk production is limited by the cow's capacity for feed intake, especially in early lactation. While varying greatly from cow to cow, feed intake is more highly correlated to daily milk yield in mid-lactation than earlier. Factors affecting intake of forage are discussed. Early harvesting in combination with proper conservation are shown to maximize the potential of forage for supporting milk production.The effects of forage quality and quantity in mixed diets are discussed in relation to rumen fermentation and milk yield response. It is emphasized that although liberal grain feeding is needed to attain high milk yield, restricted forage allowance may seriously affect milk yield and milk composition. It is concluded that the importance of forages generally declines compared to concentrates with increased milk production but that liberal feeding of high quality forages is needed to maintain normal digestion and high milk yield under practical farm conditions.     

Olfactory discrimination in the rabbit olfactory glomerulus

Slow potentials evoked by odor stimulation were recorded from individual glomeruli in the olfactory bulb. Systematic analysis of responses to nine different, arbitrarily selected stimuli strongly suggests a certain amount of discrimination. This fact seems to reflect in the first synapse of the olfactory tract the type of discrimination that was recently demonstrated within olfactory neuroepithelium.     

Clinical efficacy and safety of recombinant canine erythropoietin in dogs with anemia of chronic renal failure and dogs with recombinant human erythropoietin-induced red cell aplasia

The efficacy and safety of recombinant canine erythropoietin (rcEPO) therapy was evaluated in 19 dogs with anemia of chronic renal failure (group 1) and 6 dogs with chronic renal failure and recombinant human erythropoietin (rhEPO)-induced red cell aplasia (group 2). Hematocrit (Hct) and absolute reticulocyte count (ARC) were monitored weekly for the first 8 weeks, CBC (including ARC) and serum iron profiles were evaluated monthly, and serum biochemical analyses were performed every 2 months for 6 (group 2) to 12 (group 1) months. For group 1 dogs, median Hct and ARC increased significantly during the 1st week of rcEPO treatment, and median Hct was sustained at >35% after week 5. In contrast, median Hct and ARC for group 2 did not change significantly with rcEPO treatment, even with doses greater than those used in group 1. Nevertheless, 2 (33%) of the 6 dogs in group 2 developed erythroid hyperplasia, reticulocytosis, and increases in Hct with rcEPO treatment. Although median systolic blood pressure did not change significantly in either group, 5 dogs developed systolic blood pressures > or = 180 mm Hg during the study. Appetite and energy level improved in most group 1 dogs with increases in Hct. Recombinant cEPO stimulated erythrocyte production in dogs with nonregenerative anemia secondary to chronic renal failure without causing the profound erythroid hypoplasia that can occur in rhEPO-treated dogs. Unfortunately, rcEPO was not as effective in restoring erythrocyte production in dogs that had previously developed rhEPO-induced red cell aplasia.     

Climate change and the cetacean community of north-west Scotland

1. Climate change is thought to affect the composition and structure of local ecological communities. We investigate whether ocean warming around north-west Scotland since 1981 has been associated with changes in the local cetacean community.2. Analysis of strandings from 1948 to 2003 found that no new species per decade were recorded in north-west Scotland between 1965 and 1981. This rose to 2.0 new species per decade from 1988 onwards. The new species recorded since 1988 are generally restricted to warmer waters, while those recorded prior to 1981 regularly occur in colder waters.3. In the period 1992 to 2003, the relative frequency of stranding of white-beaked dolphin, a colder water species, has declined while strandings of common dolphin, a warmer water species, have increased. Similarly, sightings surveys conducted in May-September 2002 and 2003 show that the relative occurrence and abundance of white-beaked dolphins have declined and common dolphins increased in comparison to previous studies.4. These observations are consistent with changes in the local cetacean community being driven by increases in local water temperature. If such temperature changes continue, some formerly abundant cold-water species, such as white-beaked dolphins, may be lost from this cetacean community. In a wider context, such changes may lead to populations of cetaceans moving out of areas specifically designated for their protection as they respond to changes in local oceanic conditions.     

Qualitative and quantitative strategies of thermal adaptation of grass carp (Ctenopharyngodon idella) cytoplasmic malate dehydrogenases

Malate dehydrogenase isozymes of grass carp,Ctenopharyngodon idella, were identified by mitochondrial preparation and thermal denaturation. The structural and kinetic characteristics of chromatographically separated thermostable and thermolabile cMDHs were different in (1) half-life at 42°C, 10 min and 24 h, respectively, (2) optimal substrate, oxaloacetate and malate, concentrations, and (3) the apparent Michaelis-Menten constants of NADH and oxaloacetate.Total MDH activity in white muscle of 11°C-acclimated fish was about twice that of the 30°C-acclimated group. In addition, the ratio of the thermostable to thermolabile cMDH activity in white muscle of 30°C-acclimated fish was significantly higher than that of 11°C-acclimated fish. These results suggest that temperature acclimation can induce temperature compensation in MDH activity and differential expression of thermostable and thermolabile cMDH isozymes in freshwater fish.     

Rapid monitoring of species abundance for biodiversity conservation: Consistency and reliability of the MacKinnon lists technique

Effective monitoring of biodiversity for conservation requires information on spatial and temporal variation in species’ abundances. As conservation resources are limited, monitoring methods are required that enable rapid and cost effective data collection. There are many traditional methods of estimating absolute abundance, such as territory mapping and distance sampling. However, these typically require more time, expertise and finances than are available across much of the globe. This is especially so in the tropics, where high species richness, low densities of many species and structurally complex environments also make monitoring particularly challenging. The MacKinnon lists technique is a rapid assessment methodology designed for use in species rich environments. This method is typically used to estimate species richness, but it has also been suggested that it can generate consistent abundance indices, even when observer experience and environmental conditions vary. If this suggestion is correct, the MacKinnon lists method could be used to assess spatial or temporal changes in abundance using diverse survey data. Here, we provide the first detailed assessment of intra- and inter-observer consistency of the Mackinnon List method in generating species abundance indices that could be useful for conservation monitoring purposes. As a case study, we use one of the world’s most diverse avifaunas, that of the forested Bolivian Andes. We show that MacKinnon lists can provide species abundance indices that are consistent between observers of markedly different experience of the focal avifauna (zero to six years), and between assessments carried out in different stages of the breeding season, between which detectability of individuals differed significantly. We believe this is the first time that a biodiversity monitoring method has been demonstrated to produce consistent abundance indices for a highly diverse avian tropical assemblage. We also suggest that the MacKinnon lists methodology has the potential to be a very useful conservation monitoring tool for many taxa in species rich environments, such as the tropics.     

Comparison of biological activity and safety of recombinant canine erythropoietin with that of recombinant human erythropoietin in clinically normal dogs.

OBJECTIVE: To determine whether recombinant canine erythropoietin (rcEPO) stimulates erythropoiesis in dogs without causing the immunogenicity problem (ie, erythroid hypoplasia) associated with recombinant human erythropoietin (rhEPO). ANIMALS: 13 clinically normal dogs. PROCEDURE: Dogs were randomly assigned to 2 groups; 1 group (n = 6) received rhEPO, whereas the other group (7) received rcEPO. Both groups received SC injections of diluent for 4 weeks before initiating treatment with erythropoietin (100 U/kg of body weight, SC, 3 times/wk). Hematocrit and absolute reticulocyte count were monitored weekly, CBC were done monthly, and bone marrow aspirates for cytologic evaluation were obtained before and at 4, 8, 16, and 24 weeks during treatment. RESULTS: Weekly mean Hct and absolute reticulocyte count increased in both groups of dogs during the first 2 weeks of treatment. For dogs receiving rhEPO, precipitous decreases in reticulocyte number and more gradual decreases in Hct were associated with development of erythroid hypoplasia. Dogs receiving rhEPO developed erythroid hypoplasia by week 4 (n = 4), 8 (1), or 16 (1). With cessation of rhEPO treatment after diagnosis of erythroid hypoplasia, RBC production recovered 5 to 11 weeks (median, 7 weeks) later. In contrast, rcEPO treatment caused sustained increases in Hct and reticulocytosis. None of the dogs receiving rcEPO developed erythroid hypoplasia. CONCLUSIONS: rcEPO stimulated erythrocyte production in clinically normal dogs during a 24-week period without causing the erythroid hypoplasia encountered in rhEPO-treated dogs. CLINICAL RELEVANCE: Because rcEPO did not cause erythroid hypoplasia, rcEPO may represent an improved option, compared with rhEPO, for treatment of erythropoietin-dependent anemia in dogs.     

Rod origin of prolonged afterimages

Afterimages fade against any unchanging background but generally reappear if the background changes suddenly. Under some conditions, however, a change of background color fails to revive a faded afterimage. This happens only if the interchanged backgrounds equally stimulate the rod receptors. It follows that afterimages seen under these conditions are generated by rods.     

Continuous automated recording of ruminal pH in sheep nourished entirely by intragastric infusions

A method is described whereby the rumen pH in sheep entirely nourished by infusion of volatile fatty acids was determined continuously. The electrodes used were standard laboratory combination electrodes connected to a digital pH meter, a multi-channel chart recorder and an isolation module. The correlation between pH readings from the bench samples and from electrodes immersed in the rumen for periods of up to 28 days was 0.980 +/- 0.015 for 250 observations. There were fairly regular patterns of change in ruminal pH. The pH rose and fell by approximately 0.1 to 0.2 units over a period of about one hour. These changes were thought to be associated with periods of pseudorumination.