Retrospective comparison of surgical ligation and transarterial catheter occlusion for treatment of patent ductus arteriosus in two hundred and four dogs (1993-2003)

OBJECTIVE: To compare procedure time, complications, mortality, and short-term outcome in dogs with patent ductus arteriosus (PDA) treated by surgical ligation (SL) or transarterial coil occlusion (TCO). STUDY DESIGN: Retrospective study. ANIMALS: Dogs with PDA (n=204). METHODS: Medical records of dogs treated for PDA were reviewed. Dogs treated by SL when it was the primary method used for PDA treatment (1993-1998) were compared with dogs treated by TCO when it was the primary method used for PDA treatment (1999-2003). Dogs treated during the transition between techniques, dogs treated with SL (1999-2003) and dogs treated with TCO before 1999, as well as dogs with pulmonary hypertension, or bidirectional or reversed (right-to-left) flow through the PDA were excluded from analysis. RESULTS: Age, weight, gender distribution, and procedure times (P=.43) were similar for both groups. Major complications were more common with SL (12% versus 4.3%; P=.035) whereas minor complications were more common with TCO (12% versus 26%; P=.015). Initial success rate was higher for SL (94%) compared with TCO (84%; P=.027). There was no significant difference in mortality between SL (5.6%) and TCO (2.6%; P=.27). CONCLUSIONS: Both SL and TCO are acceptable PDA treatments with comparable mortality; however, SL was associated with a higher risk of major complications and TCO was associated with a lower initial success rate.     

Insecticide resistance in house flies from caged‐layer poultry facilities

The frequency of resistance of eight strains of house flies, Musca domestica L., collected from caged‐layer poultry facilities across New York state, to nine insecticides (dimethoate, tetrachlorvinphos, permethrin, cyfluthrin, pyrethrins, methomyl, fipronil, spinosad and cyromazine) was measured relative to a laboratory susceptible strain. Percentage survival was evaluated at five diagnostic concentrations: susceptible strain LC₉₉, 3 × LC₉₉, 10 × LC₉₉, 30 × LC₉₉ and 100 × LC₉₉. The highest levels of resistance were noted for tetrachlorvinphos, permethrin and cyfluthrin. There was substantial variation in the levels of resistance to the different insecticides from one facility to another, independent of their geographical location. There was very little cross‐resistance detected in these populations to either fipronil or spinosad. Overall, there was a good correlation between insecticide use histories and the levels of resistance. The apparent isolation of fly populations within poultry facilities suggests that there are good opportunities for the implementation of successful resistance management strategies at these facilities. Differences between these results and those of a resistance survey on New York dairy farms in 1987 are discussed. © 2000 Society of Chemical Industry     

Structural modifications increase the insecticidal activity of ryanodine

The toxicity of ryanodine ( 1 ) and 9,21-didehydroryanodine ( 2 ) (the principal active ingredients of the botanical insecticide ryania) to adult female house flies (Musca domestica L.) is attributable to binding to the ryanodine receptor (ryr) and thereby disrupting the Ca²⁺-release channel. These ryanoids, assayed in house flies with piperonyl butoxide (PBO) to suppress cytochrome P450-dependent detoxification, give injected KD₅₀ values of 0·07–0·11 μg g^-1, injected LD₅₀ values of 0·39–0·45 μg g^-1 and topical LD₅₀ values of 12– 50 μg g^-1. They inhibit the [³H]ryanodine binding site of house fly and rabbit muscle with IC₅₀ values of 3–10 nM . This study examines the effect of structure on potency, with 15 variants of the cyclohexane substituents, two 4,6-cyclic boron and two methylated derivatives, and four modifications of the isopropyl and ester substituents. The most effective compound examined was 10-deoxy- 2 ( 3 ) which was more potent than 2 by 2–4-fold on injection and 29-fold applied topically following PBO (LD₅₀ 0·41 μg g^-1). Additional high-potency compounds were 10-oxo- 1 and the cyclohexane variants with lactam, 21-nor-9-oxo and 21-nor-10-deoxy substituents. Other modifications usually reduced toxicity. The injected knockdown potency of the ester ryanoids was generally related to their effectiveness in competing with [³H]ryanodine at the ryr of rabbit skeletal muscle. Two non-ester ryanoids, ryanodol and 9,21-didehydroryanodol, were found to be more toxic than predicted from their potency at the ryr and may therefore act in a different manner such as at a K⁺ channel, as suggested by Usherwood and Vais. Clearly ryanoids are challenging prototypes for a potential new generation of insecticides. © 1997 SCI.     

Increasing Fish Oil Levels in Commercial Diets Influences Hematological and Immunological Responses of Channel Catfish,Ictalurus punctatus

Growth performance, immune responses and disease resistance were studied in juvenile channel catfish, Ictalurus punctatus, fed a commercial diet (35.3% crude protein and 5.6% lipid) supplemented with menhaden fish oil at levels of 0, 3, 6, and 9% for 15 wk. Dietary fish oil levels did not significantly influence growth performance of catfish. Fatty acid compositions of whole‐body and liver reflected dietary fatty acid composition. No differences were found in hematological values, except that fish fed the 9% fish oil diet had significantly lower hematocrit. The resistance of erythrocytes to hemolysis in hypotonic solutions increased with increasing fish oil levels and the highest resistance was seen with the 9% fish oil diet. Fish fed 6 and 9% added fish oil diets had significantly higher serum protein levels than that of control fish. Serum lysozyme activity of fish fed 3 and 6% added fish oil diet was significantly higher than that of the control. Complement activity and chemotaxis ratio significantly decreased in fish fed diets with 6 or 9% added fish oil. The 3% added fish oil diet, however, had significantly highest natural hemolytic complement activity. Mortality from Edwardsiella ictaluri 14 d postchallenge and antibody titers to E. ictaluri did not differ among treatments.     

Quantitative trait loci mapping of seed colour,hairy leaf,seedling anthocyanin,leaf chlorosis and days to flowering in F2 population of Brassica rapa L.

A diversity arrays technology (DArT) map was constructed to identify quantitative trait loci (QTL) affecting seed colour, hairy leaf, seedling anthocyanin, leaf chlorosis and days to flowering in Brassica rapa using a F₂ population from a cross between two parents with contrasting traits. Two genes with dominant epistatic interaction were responsible for seed colour. One major dominant gene controls the hairy leaf trait. Seedling anthocyanin was controlled by a major single dominant gene. The parents did not exhibit leaf chlorosis; however, 32% F₂ plants showed leaf chlorosis in the population. A distorted segregation was observed for days to flowering in the F₂ population. A linkage map was constructed with 376 DArT markers distributed over 12 linkage groups covering 579.7 cM. The DArT markers were assigned on different chromosomes of B. rapa using B. rapa genome sequences and DArT consensus map of B. napus. Two QTL (RSC1‐2 and RSC12‐56) located on chromosome A8 and chromosome A9 were identified for seed colour, which explained 19.4% and 18.2% of the phenotypic variation, respectively. The seed colour marker located in the ortholog to Arabidopsis thaliana Transparent Testa2 (AtTT2). Two QTL RLH6‐0 and RLH9‐16 were identified for hairy leaf, which explained 31.6% and 20.7% phenotypic variation, respectively. A single QTL (RSAn‐12‐157) on chromosome A7, which explained 12.8% of phenotypic variation was detected for seedling anthocyanin. The seedling anthocyanin marker is found within the A. thaliana Transparent Testa12 (AtTT12) ortholog. A QTL (RLC6‐04) for leaf chlorosis was identified, which explained 55.3% of phenotypic variation. QTL for hairy leaf and leaf chlorosis were located 0–4 cM apart on the same chromosome A1. A single QTL (RDF‐10‐0) for days to flowering was identified, which explained 21.4% phenotypic variation.     

N<Subscript>2</Subscript> fixation by faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.) in a gypsum-amended sodic soil

The response of faba bean to the application of four rates of gypsum (0, 2.5, 5.0, 10.0 t ha⁻¹) to a non-saline, alkaline sodic soil was measured in terms of grain yield, dry matter (DM) production, N accumulation and the proportional dependence of the legume on symbiotic N₂ fixation (P _atm). A yield-independent, time-integrated ¹⁵N-dilution model was used to estimate symbiotic dependence. A significant decrease in the exchangeable sodium percentage and significant increases in exchangeable Ca⁺⁺ and the Ca⁺⁺:Mg⁺⁺ ratio in the 0–10-cm soil layer were measured 30 months after application of 10 t ha⁻¹ gypsum. Despite low and erratic rainfall during crop growth, faba bean DM and N uptake responded positively to gypsum application. The symbiotic dependence of the legume at physiological maturity was little affected by sodicity (P _atm = 0.74 at zero gypsum and 0.81–0.82 at 2.5–10 t ha⁻¹ gypsum). The increase in fixed N due to gypsum application was mainly due to increases in legume DM and total N uptake. At 10 t ha⁻¹ of gypsum, faba bean fixed more than 200 kg N ha⁻¹ in above-ground biomass.     

Grain dormancy in fixed lines of white-grained wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) grown under controlled environmental conditions

Pre-harvest sprouting (PHS) in wheat (Triticum aestivum L.) can be a significant problem, causing deleterious effects on grain quality. However, the adverse impacts of PHS can be reduced by introgressing genes controlling grain dormancy into white-grained bread wheat. Screening for grain dormancy typically involves germination testing of harvest-ripe grain grown in a glasshouse or field. However, the more uniform environmental conditions provided by temperature controlled glasshouses (i.e. controlled environmental conditions—CEC) may provide significant benefits for the assessment of grain dormancy. In this study, the dormancy phenotype of grain grown under CEC incorporating an extended photoperiod, was compared with 2 years of data from field grown material. Four dormant double haploid lines (derived from SW95-50213 and AUS1408) and two locally adapted non-dormant cultivars EGA Gregory and EGA Wills were compared in three replicated experiments grown under CEC (22 ± 3°C and 24 h photoperiod). The germination response of harvest-ripe grain was examined to assess the expression of grain dormancy. Two measures of germination, the predicted time to 50% germination (G ₅₀) and a weighted germination index, both clearly differentiated dormant and non-dormant lines grown under CEC. In addition, levels of grain dormancy were similar to field-grown plants. These results demonstrated that CEC with an extended photoperiod can be used for rapid and reliable characterisation of grain dormancy in fixed lines of bread wheat.     

Effects of Yeast Oligosaccharide Diet Supplements on Growth and Disease Resistance in Juvenile Nile Tilapia,Oreochromis niloticus

Commercially available yeast and yeast subcomponents consisting mainly of β-glucan or oligosaccharide feed additives were added to diets of juvenile (12–18g) Nile tilapia (Oreochromis niloticus) at rates recommended by suppliers. Three experiments were conducted following a basic protocol with varied rates of supplementation, duration of feeding, and stocking densities. Experimental diets were fed twice daily to apparent satiation for a period of two or four weeks, at the end of which feed consumption and weight gain were measured. Following the experimental feeding period, serum components, including protein and immunoglobulin concentrations, as well as lysozyme and complement activities, were measured. A disease challenge was conducted with pathogenic isolates of Streptococcus iniae or Edwardsiella tarda. Weight gains were not significantly different in fish fed the supplemented diets when compared to the control diet. There were significant differences in fed intake within individual experiments; however, this effect was not consistent in all three experiments. Overall feed efficiency was not significantly affected by diet. There were no differences in serum components of fish sampled at two or four weeks. Fish fed the experimental diets did not have lower mortality or morbidity after disease challenge compared to fish fed the control diets. Specific antibody against S. iniae or E. tarda measured by ELISA did not reveal differences in the fish surviving the challenge. We conclude that the incorporation of these commercial yeast component products into the diet of juvenile Nile tilapia at these rates and for these feeding periods had no effect on growth, serum components, antibody responses, or survival following S. iniae or E. tarda infection.