Plasma amino acid concentrations in aggressive dogs

Following the hypothesis that metabolic screens may be useful tools in the diagnosis of canine aggression we have investigated the blood plasma amino acid levels of dogs which have been found aggressive (N = 10) against dogs or men in comparison to non-aggressive dogs (N = 10). In summary, the aggressive dogs showed elevated plasma concentrations of the neurophysiological active aromatic amino acids tryptophan (46/171 micromol/l, p < 0,001), tyrosine (38/67 micromol/l, p < 0.01) and histidine (74/91 micromol/l, p < 0.01) and lower lysine concentrations (175/151 micromol/l, p < 0.05), which seems to point to a stress situation of these dogs. The nitrogen metabolism is impaired in the urea-cycle in the conversion of ornithine (17/34 micromol/l, p < 0.01) to citrulline (64/47 micromol/l). Higher levels of branched chain amino acids, especially leucine (122/150 micromol/l, p < 0.01), mainly metabolized in muscles, and isoleucin (60/71 micromol/l, p < 0.05) show a high energy potential.The acidose-stimulator methionine (48/78 micromol/l, p < 0.01) proved elevated. The results show that the changed behavior in the aggressive dogs is also reflected in their free amino acid plasma concentrations, independent of the question whether these data are the cause or the result of the aggressivity.     

MAGNETIC RESONANCE IMAGING FINDINGS IN SPINAL CORD INFARCTION IN THREE SMALL BREED DOGS

Fibrocartilaginous embolization (FCE) of the spinal cord is a common disease in large breed dogs. There are only a few reports about this entity in small breed dogs and it has never been reported in chondrodystrophic breed. For definitive diagnosis histopathologic examination is necessary. Magnetic resonance imaging (MRI) as a potential diagnostic tool for intravitam diagnosis of FCE has been mentioned before, but results have not been reported so far. This report describes the neurological findings and MRI results in three small breed dogs, including a Pekingese dog, with FCE of the spinal cord. The disease was suspected in two animals based upon clinical and MRI-appearance and confirmed in the third by histopathological examination. In all three cases, similar focal intramedullary lesions, consisting of hyperintensive signals on T2-weighted images, were detected. Based on these findings, high-field MRI may be used as an antemortem tool for the diagnosis of FCE. It is also shown that FCE can occur in chondrodystrophic dogs.     

Biochemical study of resistance to imidacloprid in B biotype Bemisia tabaci from Guatemala

Systemic uptake bioassays using excised cotton leaves confirmed resistance to imidacloprid in a Guatemalan population of the tobacco whitefly Bemisia tabaci Gennadius. Polyacrylamide gel electrophoresis of naphthyl esterases identified the insects as B-types. Upon collection from the field, resistance was determined to be 58-fold relative to a susceptible strain originating in the Imperial Valley of California. Resistance levels increased to 126-fold in this population during its continuous exposure to systemically treated cotton. In biochemical investigations, there was no detectable NADPH-dependent mixed function oxidase metabolism of 14C-imidacloprid at any time during the selection process. In contrast, microsomal preparations from housefly abdomens readily produced significant amounts of the mono-hydroxy and olefin derivatives of the parent compound. Detoxification of imidacloprid by housefly MFOs may account for reports of lower toxicity of the insecticide towards this insect compared with whiteflies, despite similar binding properties between imidacloprid and the nicotinic acetylcholine receptors in both species.     

Preliminary results on the plasma environment of saturn from the pioneer 11 plasma analyzer experiment

The Ames Research Center Pioneer 11 plasma analyzer experiment provided measurements of the solar wind interaction with Saturn and the character of the plasma environment within Saturn's magnetosphere. It is shown that Saturn has a detached bow shock wave and magnetopause quite similar to those at Earth and Jupiter. The scale size of the interaction region for Saturn is roughly one-third that at Jupiter, but Saturn's magnetosphere is equally responsive to changes in the solar wind dynamic pressure. Saturn's outer magnetosphere is inflated, as evidenced by the observation of large fluxes of corotating plasma. It is postulated that Saturn's magnetosphere may undergo a large expansion when the solar wind pressure is greatly diminished by the presence of Jupiter's extended magnetospheric tail when the two planets are approximately aligned along the same solar radial vector.     

Evolution of supergene families associated with insecticide resistance

The emergence of insecticide resistance in the mosquito poses a serious threat to the efficacy of many malaria control programs. We have searched the Anopheles gambiae genome for members of the three major enzyme families- the carboxylesterases, glutathione transferases, and cytochrome P450s-that are primarily responsible for metabolic resistance to insecticides. A comparative genomic analysis with Drosophila melanogaster reveals that a considerable expansion of these supergene families has occurred in the mosquito. Low gene orthology and little chromosomal synteny paradoxically contrast the easily identified orthologous groups of genes presumably seeded by common ancestors. In A. gambiae, the independent expansion of paralogous genes is mainly a consequence of the formation of clusters among locally duplicated genes. These expansions may reflect the functional diversification of supergene families consistent with major differences in the life history and ecology of these organisms. These data provide a basis for identifying the resistance-associated enzymes within these families. This will enable the resistance status of mosquitoes, flies, and possibly other holometabolous insects to be monitored. The analyses also provide the means for identifying previously unknown molecules involved in fundamental biological processes such as development.     

Increased elastase activity in nasal mucus associated with nasal colonization by Pasteurella haemolytica in infectious bovine rhinotracheitis virus-infected calves.

Four healthy calves were inoculated with Pasteurella haemolytica serotype 1 by instillation of a broth culture into the middle nasal meatus of the left nostril. Four weeks later, calves were exposed to infectious bovine rhinotracheitis virus by aerosol into both nostrils. All calves became ill, from approximately day 3 through day 10 after virus exposure, and shed increased amounts of nasal mucus. Two calves were induced to shed P haemolytica by the virus infection, and 2 calves required reinoculation with P haemolytica for nasal passages to become actively colonized. Elastase activity in nasal mucus increased about 15-fold within 3 days and peaked about 60-fold over baseline by 7 days after virus exposure. Activity of N-acetyl-beta-D-glucosaminidase, a measure of cell damage and serum leakage, increased slightly by day 3 and reached plateau on day 5, almost threefold over baseline activity. Protein and carbohydrate content increased at a rate similar to that of N-acetyl-beta-D-glucosaminidase activity with about 12-fold and sixfold increases, respectively. None of the variables returned to baseline by 19 days after virus exposure. Increased elastase activity preceded colonization by P haemolytica and decreasing elastase activity preceded decreasing P haemolytica concentration in the nasal secretions. A causal relation between elastase activity and P haemolytica colonization could be mediated by cleavage of epithelial cell surface fibronectin and exposure of receptors.     

Origin of Clostridium perfringens isolates determines the ability to induce necrotic enteritis in broilers

Since the ban on growth-promoting antibiotics in animal feed in the European Union, necrotic enteritis has become a major cause of mortality in broiler chickens. Despite the importance of the disease, the pathogenesis is still not completely understood. In the current study, Clostridium perfringens strains isolated from healthy flocks and isolates from outbreaks of necrotic enteritis were evaluated for the ability to cause gut necrosis in an intestinal loop model in laying hens and in an experimental infection model in broilers. High, intermediate and low alpha toxin producing strains were chosen from each isolation source. Only the isolates from field outbreaks induced necrotic gut lesions, independent of the amount of alpha toxin produced in vitro. It was also shown that alpha toxin producing isolates from calf hemorrhagic enteritis cases were not able to induce necrotic enteritis in poultry. These results suggest the presence of host specific virulence factors in C. perfringens strains, isolated from chickens with intestinal necrotic enteritis lesions.     

Antimicrobial resistance and recovery of Salmonella,Campylobacter, and Escherichia coli from chicken egg layer flocks in Canadian sentinel surveillance sites using 2 types of sample matrices

Eggs are important to the diet of Canadians. This product is one of the supply-managed commodities in Canada, but unlike other commodities, where food safety risks are extensively explored and reported, information on the prevalence of enteric organisms (e.g., Salmonella, Campylobacter) and antimicrobial resistance (AMR) in layers in Canada are limited. This study was conducted to determine the prevalence of select bacteria and the associated AMR patterns in layer flocks using 2 sample matrices. Farms were located within FoodNet Canada and the Canadian Integrated Program for Antimicrobial Resistance Surveillance sentinel sites (SS). Fecal samples (Ontario: ON_SS1a, ON_SS1b) and environmental sponge swabs (British Columbia: BC_SS2a) were collected. Salmonella prevalence was 29% and 8% in ON_SS1a and ON_SS1b, respectively, and 7% in BC_SS2a. S. Kentucky and S. Livingstone were the most frequently isolated serovars and no S. Enteritidis was detected. Campylobacter was not detected in the BC sponge swabs but was isolated from 89% and 53% of Ontario fecal samples (ON_SS1a and ON_SS1b, respectively). Seven C. jejuni from Ontario were ciprofloxacin-resistant. Escherichia coli prevalence was high in both sample types (98%). Overall, tetracycline resistance among E. coli ranged from 26% to 69%. Resistance to ceftiofur (n = 2 isolates) and gentamicin (n = 2) was relatively low. There were diverse resistance patterns (excludes susceptible isolates) observed among E. coli in Ontario (10 patterns) and British Columbia (14 patterns). This study revealed that fecal samples are more informative for farm-level monitoring of pathogen and AMR prevalence. Without further validation, sponge swabs are limited in their utility for Campylobacter detection and thus, for public health surveillance.     

In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components

The antibacterial potential of organic acids and essential oil components against Brachyspirahyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitoryconcentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay.In addition, possible synergism was determined. MIC values for the three tested strains were similar. Fororganic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was mostsensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binarycombinations were additive, however, for thymol and carvacrol, synergism could be observed. Invitro results demonstrate the antibacterial action of certain essential oil components and organicacids against B. hyodysenteriae.     

Aktuelle Probleme bei Rückstandsuntersuchungen von Pesticiden in Gemüse und Obst

Zusammenfassung Bei den Pesticiden sorgt die Gruppe der Chlorkohlenwasserstoffe wegen ihrer Persistenz immer wieder für neue Probleme. So wird am Beispiel des DDT der momentane Erfolg einerseits und die oft unerwünschte Neben- und Langzeitwirkung andererseits deutlich, weshalb die Industrie heute spezifisch wirksame Verbindungen auf den Markt bringen will, die relativ rasch abgebaut werden. Wenn solche spezifisch wirksame Mittel in zu hoher Konzentration angewandt werden, so treten momentane Gefahren auf, die durch regelmäßige Kontrollen auf ein Mindestmaß reduziert werden können.Bei den Chlorkohlenwasserstoffen haben wir neben der momentanen Gefahr noch die große Gefahr der Langzeitwirkung, die man nur durch Präventivmaßnahmen, gelegentlich auch als Stuttgarter Modell bezeichnet, einschränken kann. Am Beispiel des früher zugelassenen Brassicols wird gezeigt, daß auch Jahre danach der Anbau bestimmter Kulturen stark gefährdet ist, wenn eine starke und nachhaltige Kontamination des Bodens mit Hexachlorbenzol vorliegt. Ähnliches gilt für stark mit Dieldrin kontaminierte Gewächshauserden, deren Ursache die lang zurüchliegende Anwendung aldrinhaltiger Mittel ist. Durch regelmäßige Kontrolle der Böden wird der Grad der Kontamination ermittelt und aufgrund der Erfahrung aus anderen Untersuchungsergebnissen kann dann die bestehende Gefahr durch Anbau entsprechender Kulturen überbrückt werden.Ein wesentliches Kriterium der Überwachung ist es, nicht nur die momentane Gefahr, sondern darüber hinaus auch die mögliche Langzeitgefahr zu erkennen und den Verbraucher davor zu schützen.

---

Actual problems of residue control in fruits and vegetables

The pesticides esspecially the chlorinated hydrocarbons always create new problems due to their persistence. The DDT e.g. is the best example for its temporary effectiveness as it shows quite clearly long term side effects. That is the reason that chemical industries today try to produce specific substances which loose those effects quickly. However, if such substances are used without care or precautions e.g. too high a concentration and or without the necessary waiting time, there are temporary dangers. These acute problems can be easily diminished with careful controls.The long term effect of the chlorinated hydrocarbons can be only reduced by preventive controls, sometimes called Stuttgarter Modell.It is desribed, that Brassicol^®used years before can cause high contamination of soil and plants. It is also shown, that the soil and some plants can be contaminated with dieldrin years after application of aldrin.First of all the control of soil contamination is necessary. According to the residues of HCB, dieldrin or other chlorinated hydrocarbons the cultivation of certain plants (cress, parsley, carrots, radishes and so on) is at the moment not recommended.It is important, that the official control detects not only the actual danger, more essential is to watch for long term effects and keep it away from people.

---

---

Vortrag, gehalten am 30.9.1976 anläßlich der Jahrestagung der Deutschen Gesellschaft für Qualitätsforschung (Pflanzliche Nahrungsmittel) in Geisenheim/Rheingau.