The resistance of meat chickens vaccinated by aerosol with a live V4 Newcastle disease virus vaccine in the field to challenge with a velogenic Newcastle disease virus

Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.     

Leaf respiratory acclimation to climate: comparisons among boreal and temperate tree species along a latitudinal transect

In common gardens along an ～900 km latitudinal transect through Wisconsin and Illinois, U.S.A., tree species typical of boreal and temperate forests were compared with respect to the nature and magnitude of leaf respiratory acclimation to contrasting climates. The boreal representatives were trembling aspen (Populus tremuloides Michx.) and paper birch (Betula papyrifera Marsh.), while the temperate species were eastern cottonwood (Populus deltoides Bartr ex. Marsh var. deltoides) and sweetgum (Liquidambar styraciflua L.). Assessments were conducted on seedlings grown from seed sources collected near southern and northern range boundaries, respectively. Nighttime rates of leaf dark respiration (R(d)) at common temperatures, as well as R(d)'s short-term temperature sensitivity (energy of activation, E(o)), were assessed for all species and gardens twice during a growing season. Little evidence of R(d) thermal acclimation was observed, despite a 12 °C range in average air temperature across gardens. Instead, R(d) variation at warm temperatures was linked most closely with prior leaf photosynthetic performance, while R(d) variation at cooler temperatures was most strongly related to leaf nitrogen concentration. Moreover, E(o) differences across species and gardens appeared to stem from the somewhat independent limitations on warm versus cool R(d). Based on this construct, an empirical model relying on R(d) estimates from leaf photosynthesis and nitrogen concentration explained 55% of the observed E(o) variation.     

The nutritional status of asymptomatic HIV-infected Africans: directions for dietary intervention?

OBJECTIVE: To compare the relationships between food (nutrient) intakes and biochemical markers of nutritional status of asymptomatic HIV-infected with HIV-uninfected subjects, to gain more information on the appropriate diet for HIV-infected persons at an early stage of infection. DESIGN: Cross-sectional population-based survey. SETTING: North West Province, South Africa. SUBJECTS: Two hundred and sixteen asymptomatic HIV-infected and 1550 HIV-uninfected men and women volunteers aged 15 years and older, recruited as 'apparently healthy' subjects from 37 randomly selected sites. OUTCOME MEASURES: Food and nutrient intakes, measured with a validated food-frequency questionnaire, and nutritional status indicated by anthropometric and biochemical variables, measured by a standardised methodology. RESULTS: The prevalence of HIV infection in the study population was 11.9%. The anthropometric indices and nutrient intakes of HIV-infected and uninfected subjects did not differ significantly, indicating that these 216 HIV-infected subjects were at an early stage of infection. Of the biochemical nutritional status variables, high-density lipoprotein cholesterol and total cholesterol, haemoglobin, albumin and triglycerides were significantly lower in infected subjects. They also had higher globulin and liver enzyme levels than uninfected subjects. In infected subjects, serum albumin correlated significantly with serum lipids, serum vitamin A, serum vitamin E, serum iron, total iron-binding capacity and haemoglobin. The significant positive correlations of the liver enzymes with serum lipids, albumin, vitamin A and iron, observed in HIV-uninfected subjects, disappeared in the infected subjects. Polyunsaturated fat intake showed significant positive correlations with the increased liver enzymes in infected subjects. A principal components analysis indicated that, in infected subjects, increased liver enzymes correlated with higher consumption of maize meal and lower consumption of meat and vegetables. CONCLUSIONS AND RECOMMENDATIONS: This survey indicated that asymptomatic HIV-infected subjects who followed a diet rich in animal foods had smaller decreases in serum albumin, haemoglobin and lipid variables, and smaller increases in liver enzymes, than those who consumed a diet based on staple foods. This suggests that animal foods are associated with improved nutritional status in HIV-infected persons. These results should be confirmed with intervention studies before dietary recommendations for asymptomatic HIV-infected individuals can be made.     

Boundary layer profiles in plasma chemical vapor deposition

A nonlinear optical spectroscopy based on degenerate four-wave mixing has made possible direct measurements of species temperature and concentration profiles through the boundary layer of a reactive plasma at atmospheric pressure. Spectra were obtained for CH and C(2) radicals over a range of conditions including those for the plasma chemical vapor deposition of diamond films. Numerical simulations based on a one-dimensional stagnation-point flow model are in good agreement with the measurements. The CH mole fraction is shown to rise and fall as a function of distance from the substrate, which is compelling experimental evidence for the complex chemistry that is occurring in the plasma boundary layer.     

Tumor DNA structure in plant cells transformed by A. tumefaciens

Crown gall tumors are induced in plants by infection with the soil bacterium Agrobacterium tumefaciens. Because the tumor induction involves transfer of a portion of the tumor-inducing (Ti) plasmid DNA from the bacterium to the plant cells, this system is of interest for the study of genetic exchange as well as tumor induction. The boundaries of the transferred DNA (T-DNA) have been cloned from transformed plant cells of tobacco. Detailed mapping with restriction enzymes and nucleotide sequence analysis of two independent clones were used to study the molecular structure of the ends of the T-DNA. One clone contains the two ends of the T-DNA joined together; the other contains one end of the T-DNA joined to repetitive plant DNA sequences. These studies provide direct evidence that the T-DNA can be integrated into the plant genome. In addition, the data suggest that in the plant, T-DNA can be tandemly repeated. Sequence analysis of the junction of crown gall clone 1 reveals several direct repeats as well as an inverted repeat; these structures may be involved in the transfer of the DNA from Agrobacterium to plant cells.     

Preliminary investigation of concurrent administration of phenylbutazone and romifidine in healthy horses

ObjectiveTo characterize the cardiorespiratory and electrocardiographic effects of the combined administration of phenylbutazone and romifidine.Study designProspective four-period, four-treatment, blinded, randomized, crossover trial.AnimalsFive, healthy, mixed breed horses.MethodsPrior to treatment administration, a catheter was introduced into the intra-thoracic cranial vena cava via the jugular vein and a subcutaneously located carotid artery was catheterised. All treatments were administered intravenously (IV) and consisted of saline placebo (PLC), phenylbutazone (PBZ, 4.4 mg kg^?1) romifidine (ROM, 80 μg kg^?1) and a combination of phenylbutazone (4.4 mg kg^?1) and romifidine (80 μg kg^?1). There was at least a 1 week washout period between treatments. Heart rate (HR), respiratory rate (f_R), systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures and central venous pressure (CVP) were recorded for baseline (prior to drug administration) and at 5 minute intervals thereafter for 30 minutes. Electrocardiographic abnormalities were recorded. Data were analyzed by anova.ResultsFor the cardiovascular variables there were no statistically significant (p > 0.05) differences between horses treated with ROM and PBZ_ROM. Statistically significant (p < 0.05) differences only occurred between treatments with romifidine (ROM and PBZ_ROM) and without romifidine (PLC and PBZ). Within treatments, for ROM, changes over time were statistically significant (p < 0.05) for HR, SAP, DAP, MAP and CVP. For PBZ_ROM, changes over time were statistically significant (p < 0.05) for CVP. Sino-atrial and atrio-ventricular blocks occurred in horses treated with ROM and PBZ_ROM.Conclusions and clinical relevanceThe combined IV administration of phenylbutazone and romifidine had no statistically significant effect on cardiorespiratory variables. These limited data suggest no evidence why both agents should not be included in a preoperative medication protocol for healthy horses but do not exclude the possibility of interactions occurring in a larger population.     

Enzyme electrophoresis of South African Schistosoma mattheei and S. haematobium

As a pilot project of a study undertaken to determine the influence of S. mattheei X S. haematobium hybridization on various South African S. mattheei populations by means of biochemical-taxonomic methods, a comparative electrophoretic study of laboratory-maintained S. mattheei and S. haematobium was performed, using 11 enzymes representing 16 gene loci. Eleven loci were found to be monomorphic, while 5 differed interspecifically. Computation of the results revealed that South African S. mattheei and S. haematobium are fairly closely related when compared with other Schistosoma spp. groups.     

The experimental production of big liver and spleen disease in broiler breeder hens

SUMMARY Big liver and spleen disease (BLS) was reproduced experimentally by intravenous (IV) and oral (PO) administration of BLS inocula to susceptible broiler breeder hens 34 to 36 weeks of age. Serological and pathological signs of BLS similar to those seen in the natural disease occurred in inoculated and in-contact birds. Splenomegaly was the earliest and often the only necropsy finding, with hepatomegaly and kidney enlargement occurring in some birds later in the course of the disease. After IV administration, serum antigen was detected between 2 and 4 weeks, and antibody between 3 and 5 weeks. After PO administration, antigen was detected between 2 and 4 weeks, and antibody between 3 and 6 weeks. Antibody persisted in all birds to the end of the experiment (6 weeks), and horizontal transmission probably occurred since in-contact birds developed BLS. Liver probably contained the highest concentration of BLS agent because it had the highest infectivity.     

Further observations on the electrophoretic characterization of South African Schistosoma mattheei and S. haematobium

Eleven enzymes, which were used to compare South African S. mattheei and S. haematobium in a former study, were employed to study intraspecific variation within S. mattheei, using starch gel electrophoresis and iso-electric focusing where resolution in starch gel was poor. Acid phosphatase varied intraspecifically within S. mattheei in that the most southern population differed from the northern populations. Malate dehydrogenase also varied intraspecifically. Three populations which occur sympatric with S. haematobium had a MDH-1 allele in common with the human schistosome while an allopatric population did not.