Identification of heterologous monoclonal antibodies that cross-react with cervine leukocyte subpopulations

The degree to which cross-reactivity between monoclonal antibodies developed against cells of the human, mouse, bovine and ovine immune systems, and cells of the cervine immune system occurs was investigated. It was found that within the ruminants a considerable degree of cross-reactivity does exist while there is virtually none between the cervine and murine or human systems. The highest incidence of cross-reactivity was found between ovine monoclonals and cervine leukocytes (46% cross-reactive) with 25% of bovine monoclonal antibodies cross-reacting with deer leukocytes. Ovine monoclonals were found to be the most useful in identifying a wide range of cervine leukocyte subpopulations. Bioassays showed that ovine anti-class I and II monoclonals detected molecules on cervine leukocytes that are functionally similar to MHC antigens. The possibility that cross-reactive monoclonals detect similar subpopulations in both the homologous and heterologous species is discussed.     

Efficacy of a cold-adapted, intranasal, equine influenza vaccine: challenge trials.

A randomised, controlled, double-blind, influenza virus, aerosol challenge of horses was undertaken to determine the efficacy of a cold-adapted, temperature sensitive, modified-live virus, intranasal, equine influenza vaccine. Ninety 11-month-old influenza-na?ve foals were assigned randomly to 3 groups (20 vaccinates and 10 controls per group) and challenged 5 weeks, 6 and 12 months after a single vaccination. Challenges were performed on Day 0 in a plastic-lined chamber. Between Days 1 and 10, animals were examined daily for evidence of clinical signs of influenza. Nasal swabs for virus isolation were obtained on Day 1 and Days 1 to 8 and blood samples for serology were collected on Days 1, 7 and 14. There was no adverse response to vaccination in any animal. Following challenge at 5 weeks and 6 months, vaccinates had significantly lower clinical scores (P = 0.0001 and 0.005, respectively), experienced smaller increases in rectal temperature (P = 0.0008 and 0.0007, respectively) and shed less virus (P<0.0001 and P = 0.03, respectively) over fewer days (P<0.0001 and P = 0.002, respectively) than did the controls. After the 12 month challenge, rectal temperatures (P = 0.006) as well as the duration (P = 0.03) and concentration of virus shed (P = 0.04) were significantly reduced among vaccinated animals. The results of this study showed that 6 months after a single dose of vaccine the duration and severity of clinical signs were markedly reduced amongst vaccinated animals exposed to a severe live-virus challenge. Appropriate use of this vaccine should lead to a marked reduction in the frequency, severity and duration of outbreaks of equine influenza in North America.     

The purification and characterisation of cervine IgM and IgG

A procedure is described for the isolation of immunoglobulin G (IgG) and immunoglobulin M (IgM) from hyperimmune cervine serum. Hybrids of red deer (Cervus elaphus) and wapiti (Cervus canadensis) were immunised with keyhole limpet hemocyanin (KLH). An immunoglobulin-containing fraction was precipitated from the hyperimmune serum using ammonium sulphate. The antigen-specific immunoglobulins were purified by KLH-conjugated sepharose affinity chromatography and further separated into IgM and IgG by gel-filtration chromatography. Purified immunoglobulin was analysed by polyacrylamide gel electrophoresis and isoelectric focusing. The molecular weights and isoelectric points of the composite chains of cervine IgG and IgM are presented.     

Naphthalophos combinations with benzimidazoles or levamisole as effective anthelmintics for sheep

Objective: To investigate the relative efficacy and safety of the anthelmintic naphthalophos in sheep, either given alone or in combination with benzimidazole (fenbendazole and albendazole) or levamisole anthelmintics.
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option.     

Detection of molecular markers linked to the durable adult plant stripe rust resistance gene Yr18 in bread wheat (Triticum aestivum L.)

Stripe rust of wheat caused by Puccinia striiformis West. f. sp. tritici presents a serious problem for wheat production worldwide, and identification and deployment of resistance sources to it are key objectives for many wheat breeders. Here we report the detection of simple sequence repeat (SSR) markers linked to the durable adult plant resistance of cv. ‘Otane’, which has conferred this resistance since its release in New Zealand in 1984. A double haploid population from a cross between ‘Otane’ and the susceptible cv. Tiritea’ was visually assessed for adult plant infection types (IT) in the glasshouse and field, and for final disease severity in the field against stripe rust pathotype 106E139A⁺. At least three resistance loci controlled adult plant resistance to stripe rust in this population. Quantitative trait loci (QTL) mapping results revealed that two of these, one on chromosome 7DS corresponds to the durable adult plant resistance gene Yr18 and other on chromosome 5DL were contributed from ‘Otane’; while the remaining one on chromosome 7BL, was contributed from the susceptible ‘Tiritea’. Interval mapping placed the ‘Otane’‐resistant segment near the centromere of chromosome 7DS at a distance of 7 cM from the SSR marker gwm44. The stability of QTL in the two environments is discussed. SSR gwm44 is potentially a candidate marker for identifying the durable resistance gene Yr18 in breeding programmes.     

Assessment of obesity and fear of fatness among inner-city Dublin schoolchildren in a one-year follow-up study

BACKGROUND: Positive secular trends in adolescent obesity and an increased prevalence of fear of fatness, particularly among girls, have been documented world-wide. There is a lack of consensus about assessment criteria for childhood obesity and no standard exists for assessing Irish children. In 1990, the Irish National Nutrition Survey used body mass index (BMI) > or =26 kg m(-2) to describe the prevalence of overweight among Irish adolescents. OBJECTIVES: (1) To examine the range in classification of Dublin schoolchildren as overweight according to four standard assessment methods; (2) to assess changes in weight status, prevalence of fear of fatness and accompanying slimming practices in a one-year follow-up; and (3) to compare the prevalence of overweight with that documented in 1990 among adolescents of similar age. DESIGN: A one-year follow-up study of 199 healthy schoolchildren (90 boys and 109 girls; mean age of 11 years at baseline) attending seven fee-paying (six single- and one mixed-sex) and eight non-fee-paying (four single- and four mixed-sex) primary schools in Dublin city centre. MEASUREMENTS: Weight, height, waist circumference and triceps skinfold were measured and used in five definitions of overweight, including published cut-off points of BMI-for-age (Centers for Disease Control and Prevention BMI-for-age charts for boys and girls; BMI reference curves for the UK 1990; International Obesity Task Force age- and sex-specific BMI cut-offs), actual relative weight and BM > or =26 kg m(-2). Assessment of body image perceptions and satisfaction (using figure line drawings) was reported in a questionnaire specifically designed for this study. RESULTS: The prevalence of overweight within the total group differed between the four standard definitions of weight status, by 9% at baseline and 8% at follow-up. Accordingly, increasing trends over the year ranged from zero to 3%. Using the criterion BMI > or =26 kg m(-2), 6% of Dublin schoolchildren were overweight, compared with 1.9% of schoolchildren in 1990. Significantly more girls than boys were affected by fear of fatness and were trying to lose weight. CONCLUSION: A standard method for assessment of weight status is urgently needed for the evaluation of obesity prevention initiatives among Irish schoolchildren. Such initiatives need to be sensitive to the pervasiveness of fear of fatness among adolescent girls.     

Differentiation of physical from chemical toxicity in solid waste fish bioassays

This study showed that particulate (i.e., physical) toxicity was responsible for rainbow trout deaths in bioassays with two separate solid wastes. This conclusion was based on: (1) fish necropsies which indicated physical damage to gills but no evidence of chemical damage to liver or kidney, (2) chemical analyses which indicated that levels of Priority Pollutants and other target compounds were too low to cause the observed toxicity, (3) structural and chemical analyses of the waste particles which showed that these consisted of inert materials, and (4) the use of centrifugation techniques to remove most of the suspended particulate material in bioassay tanks resulting in an elimination of most of the toxicity. The particles associated with the lethal effects were approximately 5 to 10 μm in size. Regulatory testing of solid wastes must distinguish physical and chemical toxicity since disposal options can vary depending on the mode of toxicity. For instance, chemical toxicity raises concern regarding leaching through soils into groundwater, whereas if physical particles are responsible for toxicity, such leaching is not of concern.     

Effects of leaf age and tree size on stomatal and mesophyll limitations to photosynthesis in mountain beech (Nothofagus solandrii var. cliffortiodes)

Mesophyll conductance, g(m), was estimated from measurements of stomatal conductance to carbon dioxide transfer, g(s), photosynthesis, A, and chlorophyll fluorescence for Year 0 (current-year) and Year 1 (1-year-old) fully sunlit leaves from short (2 m tall, 10-year-old) and tall (15 m tall, 120-year-old) Nothofagus solandrii var. cliffortiodes trees growing in adjacent stands. Rates of photosynthesis at saturating irradiance and ambient CO(2) partial pressure, A(satQ), were 25% lower and maximum rates of carboxylation, V(cmax), were 44% lower in Year 1 leaves compared with Year 0 leaves across both tree sizes. Although g(s) and g(m) were not significantly different between Year 0 and Year 1 leaves and g(s) was not significantly different between tree heights, g(m) was significantly (19%) lower for leaves on tall trees compared with leaves on short trees. Overall, V(cmax) was 60% higher when expressed on the basis of CO(2) partial pressure at the chloroplasts, C(c), compared with V(cmax) on the basis of intercellular CO(2) partial pressure, C(i), but this varied with leaf age and tree size. To interpret the relative stomatal and mesophyll limitations to photosynthesis, we used a model of carbon isotopic composition for whole leaves incorporating g(m) effects to generate a surface of 'operating values' of A over the growing season for all leaf classes. Our analysis showed that A was slightly higher for leaves on short compared with tall trees, but lower g(m) apparently reduced actual A substantially compared with A(satQ). Our findings showed that lower rates of photosynthesis in Year 1 leaves compared with Year 0 leaves were attributable more to increased biochemical limitation to photosynthesis in Year 1 leaves than differences in g(m). However, lower A in leaves on tall trees compared with those on short trees could be attributed in part to lower g(m) and higher stomatal, L(s), and mesophyll, L(m), limitations to photosynthesis, consistent with steeper hydraulic gradients in tall trees.