Transcatheter Thoracic Duct Embolization in the Dog An Experimental Study

Thoracic duct embolization was created by injecting an isobutyl 2-cyanoacrylate/iophendylate (IBCA) mixture through a cannulated mesenteric lymphatic vessel in eight normal dogs. Aqueous contrast lymphangiography was repeated at minute 10 and week 6. Six dogs were euthanatized at week 6 and two dogs at month 6. Embolization with 1.5 to 3.9 ml of the mixture resulted in complete obstruction of the thoracic duct in all eight dogs. Results of lymphangiography in six dogs at week 6 showed a persistent, complete obstruction of the thoracic duct in six dogs and alternate lymphaticovenous anastomoses in four dogs. Histologically, there were a sclerosing granulomatous response surrounding the lymphatic embolus, mild congestive changes in the mesenteric lymph nodes, and mild lacteal dilatation in the jejunum. The procedure was well tolerated with only a few complications. One dog suffered partial thrombosis of the cranial vena cava by the injected material with later dislodgement and embolization of a pulmonary artery branch. Modifications have been made in the injection procedure to avoid this complication. This technique for occlusion of the thoracic duct shows potential for clinical use in the management of canine chylothorax. The obstruction appears to be complete and permanent, and surgical/anesthetic time is decreased greatly from previously described procedures.     

The degradation of simazine, linuron and propyzamide in different soils

Simazine, linuron and propyzamide were incubated in 18 different soils at 25°C and field capacity soil moisture content. The degradation of each herbicide followed first-order kinetics. The half-life of simazine varied from 20 to 44 days, that of linuron from 22 to 86 days and that of propyzamide from 10 to 32 days. The rate of linuron degradation was highly significantly correlated with soil organic matter content, clay content, soil respiration and the extent of herbicide adsorption by the soil. The rate of simazine degradation was significantly and negatively correlated with soil pH, but the rate of propyzamide degradation was not related with any of the soil factors examined.     

Mammary Adenomas in a Male Dog—Probable Oestrogenic Neoplasms

Abstract— The case history is recorded of a male bilateral cryptorchid dog presented with rapidly developing mammary adenomas. A Sertoli-cell tumour was suspected and, after surgical removal of the adenomas, bilaterai orchidectomy was performed. The right retained testicle was found to be the site of a large Sertoli-cell tumour, the left of a seminoma. The pathological findings are described and a probable oestrogenic aetiology is postulated for the adenomas.
Résumé— On rapport l'histoire d'un chien måle présentant une cryptorchidie bilatérale coexistant avec des adtnomes mammaires à développement rapide. On suspecte une tumeur des cellules de Sertoli et après ablation chirurgicale de l'adéome, on a entrepris une castration bilateralé. Le testicule droit présentait une irnportante tumeur des cellules de Sertoli et le gauche un séminome. Les résultats de l'analyse anatomopathologique sont rapportés et il est avancé l'hypothèse d'une étiologie oestrogénique pour les adénomes de la glande mammaire.
Zusammenfassung— Der Fall eines Hundes mit beidseitigem Kryptorchismus und schnell wachsenden Brustdrusenadenornen wird beschrieben. Es bestand Verdacht auf einen Sertolizel-lenturnor, und nach der operativen Entfernung der Adenome wurde eine beidseitige Orchidek-tomie durchgefuhrt. Der rechte verhaltene Hoden enthielt eiene großen Sertolizellentumor, der linke ein Seminom. Die pathologischen Befunde werden beschrieben, und es wird als wahrs-heinlich angenommen, daß die Adenome östrogenischer Ätiologie sind.     

Diagnostic ultrasound in veterinary practice: How safe is it?

This paper provides information on the safety of ultrasonic diagnostic procedures as currently used in veterinary practice. The known mechanisms of action are described and selected literature on biological effects of ultrasound is reviewed. Current international consensus is presented on the safety of medical ultrasound with respect to thermal effects. To date, there is no independently verified clinical evidence that the level of exposure delivered to the tissues during scanned grey-scale (‘B-mode’) imaging has any adverse effects. Lung haemorrhage has been observed in animal experiments using diagnostic exposures, but the effects have not been reported in the foetus. Equipment that uses pulsed Doppler transmits higher acoustic outputs in a stationary beam, and can produce temperature increases that may have significant biological consequences. When considering sonographic and pulsed Doppler examinations of the prenatal animal, the safety margins are small and the operator should be aware of the acoustic output of the equipment, the exposure time, and the sensitivity of target tissues.     

Evaluation of three pesticide leaching models with experimental data for alachlor, atrazine and metribuzin

The persistence and movement of residues of alachlor, alrazine and metribuzin were measured in a mini-lysimeter system in the field. This comprised a number of soil columns (11 cm diametert; 30 cm long), and permitted the vertical distribution of residues to be determined at. intervals alter application and the collection and analysis of leaehale water. Laboratory experiments were also performed to determine the degradation rates of the three herbicides and their strengths of adsorption by the test soil. The results showed an order of degradation rate of metribuzin> alachlor>atrazine and an order of adsorption of alacblor>atrazine>melribuzin. Movement of residues in the soil columns and concentrations in the leachate were inversely related to the strength of adsorption. Parameters derived from the laboratory data were used in conjunction with weather data for the period of the field experiment in three mathematical models of pesticide leaching: VARLEACH, LEACHP and PRZM2. In most instances, the models gave acceptable predictions of the distribution of residues in soil. This was particularly so for the less mobile compound alachlor. With the most mobile compound, metribuzin, residues were not well predicted at the later sampling dates. All three models gave accurate predictions of the volumes of drainage water, but none of them predicted the concentrations of herbicide in the leachate, presumably because they do not take account of preferential flow pathways of water and solute in the soil.     

Standardization of Pest Assessment1

The first need in forecasting, in decision making in pest management on an economic base, for research and in breeding for resistance, is a good method of pest or disease assessment. This should be standardized, quantitative, repeatable, quick and simple, and give details of the signs of attack and effect on the crop. Examples of this approach from drafted or published FAO Crop Loss Assessment Methods are given, one for assessment of nymphs and bugs of the Sunn pest complex on cereals, one on Dacus fly on olives, and one on Aonidiella scale on citrus leaves. The need for continued international cooperation in developing, publishing and testing assessment methods is stressed. Une méthode fiable d'avaluation de L'incidence des ravageurs et des maladies constitue l'élément fondamental sur lequel doivent pouvoir s'appuyer les prévisions, la sélection de cultivars résistants et toute autre décision prise dans le cadre dun système de lutte integrée. Les techniques normalisées, simples et rapides, mises en ceuvre pour apprécier la signification des déprédateurs, devraient également faire état de la symptomatologie et de L'effet que ceux-ci exercent sur la culture. L'auteur cite des exemples de méthodes d'valuation des pertes de récoltes publicées par I'OAA ou en voie d'étude en se référant plus particulièrement au dénombrement des nymphes et des adultes de differentes espèces d'Eurygaster et Aelia sur céréales, et a ceiui de Dacus oleue sur olivier et d'anonidiella aurantii sur feuilles d'agrumes. Le developpement, la publication et l'évaluation des méthodes exigent une cooperation internationale suivie.     

The relative movement and persistence in soil of chlorsulfuron, metsulfuron-methyl and triasulfuron

Summary. Adsorption and degradation rates of triasulfuron in 8 different soils were negatively correlated with soil pH and were generally lower in subsoils than in soils from the plough layer. The half-life at 20°C varied from 33 days in a top soil at pH 5·8 to 120 days in a subsoil at pH 7·4. Adsorption distribution coefficients in these two soils were 0·55 and 0·19, respectively. Movement and persistence of residues of chlorsulfuron, triasulfuron and metsulfuron-methyl were compared in a field experiment prepared in spring 1987. Triasulfuron was less mobile in the soil than the other two compounds. Residues of all three herbicides were largely confined to the upper 40–50 cm soil 148 days after application. With an initial dose of 32 g ha⁻¹, residues in the surface soil layers were sufficient to affect growth of lettuce and sugar-beet sown approximately one year after application. Laboratory adsorption and degradation data were used with appropriate weather data in a computer model of herbicide transport in soil. The model gave good predictions of total soil residues during the first five months following application, and also predicted successfully the maximum depth of penetration of the herbicides into the soil during this period. However, more herbicide was retained close to the soil surface than was predicted by the model. The model predicted extensive movement of the herbicides in the soil during winter but did not predict that residues sufficient to affect crop growth could be present in the upper 15–20 cm soil after one year.     

Applying the double knock technique to control Conyza bonariensis

Sequential applications of glyphosate followed by another postemergent herbicide, known as the "double knock" technique, were trialled for their effectiveness in controlling Conyza bonariensis . Combinations of glyphosate with and without 2,4-D followed by paraquat plus diquat, paraquat, or 2,4-D were tested at a range of follow-up application times in two field and two pot experiments. The results showed that paraquat plus diquat or paraquat following glyphosate or glyphosate plus 2,4-D provided highly effective weed control compared to glyphosate alone. The optimum timing for follow-up applications of paraquat or paraquat plus diquat was between 5 and 7 days after the initial glyphosate application. Combined applications of glyphosate and 2,4-D, compared to split applications, were not significantly different. However, following glyphosate application with 2,4-D >1 day later considerably reduced the level of control. This study showed that the double knock technique is highly effective in controlling C. bonariensis and is rapidly becoming an important tool in the management of this problem weed.