Determination of extractable and non-extractable radioactivity from prairie soils treated with carboxyl- and ring-labelled [14C]2,4-D

Ring- and carboxyl-labelled [¹⁴C]2,4-D were incubated under laboratory conditions, at the 2 g/g level, in a heavy clay, sandy loam, and clay loam at 85% of field capacity and 20 1C. The soils were extracted at regular intervals for 35 days with aqaeous acidic acetonitrile, and analysed for [¹⁴C]2,4-D and possible radioactive degradation products. Following solvent extraction, a portion of the soil residues were combusted in oxygen to determine unextracted radioactivity as [¹⁴C]carbon dioxide. The remaining soil residues were then treated with aqueous sodium hydroxide, and the radioactivity associated with the fulvic and humic soil components determined. In all soils there was a rapid decrease in the amounts of extractable radioacitivity, with only 5% of that applied being recoverable after 35 days. All recoverable radioactivity was attributable to [¹⁴C]2,4-D, and no [¹⁴C]-containing degradation products were observed. This loss of extractable radioactivity was accompanied by an increase in non-extractable radioactivity. Approximately 15% of the applied radioactivity, derived from carboxyl-labelled [¹⁴C]2,4-D, and 30% from the ring-labelled [¹⁴C]2,4-D was associated with the soil in a non-extractable form, after 35 days of incubation. After 35 days, less than 5% of the radioactivity from the carboxyl-labelled herbicide, and less than 10% of the ringlabelled material, was associated with the fulvic components derived from the three soils. Less than 5% of the applied radioactivities were identifiable with any of the humic acid components. It was considered that during the incubation [¹⁴C]2,4-D did not become bound or conjugated to soil components, and that non-extractable radioactivity associated with the three soil types resulted from incorporation of radioactive degradation products, such as [¹⁴C]carbon dioxide, into soil organic matter.     

Equine wound management: are there significant differences in healing at different sites on the body?

Abstract Trunk/body wounds heal rapidly with prominent Contraction while wounds on the limb commonly fail to heal or heal slowly by centripetal epithelialization. often with insignificant contraction. Chronic exuberant granulating wounds on the limbs heal well after grafting from donor sites on the trunk. Indolent wounds are less common but may granulate significantly following moist wound-healing management. Sarcoid transformation is an increasingly important cause of healing failure. Sarcoid transformations on the trunk are commonly verrucose while those on the limb are usually aggressive and fibroblastic. The primary objective of wound management should be to encourage rapid progression from acute inflammation to repair without intervention of chronic inflammation which is a significant factor in the pathophysiology of wound healing failure. Wounds fail to heal because there is disruption of the normal delicate balance of growth factors and inflammatory mediators. Wounds should be managed in such a way as to restore the balance of healing processes without damaging any of the cells involved in healing. Resumen Las heridas localizadas en el cuerpo o tronco curan rapidamente con contracción elevada, mientras que las de las extremidades no curan o curan lentamente por epitelización centrípeta, a menudo con contracción insignificante. Las heridas crónicas con tejido de granulación exhuberantes en las extremidades curan bien después de injertos a partir de áreas del tronco. Las heridas indolentes son menos frecuentes pero pueden granular significativamente después de un manejo húmedo de la curacion de la herida. La transformación sarcoidal es una causa cada vez más frecuente de fracaso de la curación. Las transformaciones sarcoidales en el tronco son generalmente de tipo verrucoso mientras que las de las extremidades son normalmente agresivas y fibroblásticas. El objetivo principal del manejo de heridas tendría que ser la estimulación de una progresión rápida de una inflamación aguda a la resolución sin intervención de inflamación crónica, que es un factor significativo en la patofisiología del fracaso en la curación de heridas. Las heridas no curan porque se produce una alteración en el frægil equilibrio normal de factores de crecimiento y mediadores inflamatorios. Las heridas tendrian que ser manejadas de forma que se restaure el equilibrio del proceso curativo sin dañar ninguna de las células implicadas en la curacion. [Knottenbelt, D.C. Equine wound management: are there significant differences in healing at different sites on the body? (Manejo de heridas equinas: existen diferencias significativas en la curación en diferentes areas cutaneas?). Veterinar.): Dermatology 1997; 8 : 273–290] Zusammenfassung Wunden am Rumpf heilen schnell und mit deutlicher Kontraktion, während sich Wunden an den Gliedmassen oft nur geringfügig zusammenziehen und entweder gar nicht oder nur langsam vom Rande her epithelisieren. Chronische, stark wuchernde Wunden an den Gliedmassen heilen nach Gewebetransplantation vom Rumpf zufriedenstellend. Indolente Wunden sind weniger häfig, können aber nach benetzender Wundversorgung deutlich granulieren. Sarkoide Transformation ist ein wichtiger Grund für Wundheilungstörungen. Sarkoide Transformationen am Rumpf sind gewöhnlich warzig, jene an den Gliedmassen üblicherweise aggressiv und fibroblastisch. Das wichtigste Ziel der Wundversorgung sollte es sein, eine schnelle Entwicklung von akuter Entzündung zur Heilung zu fördern, ohne in die chronische Entzündung einzugreifen, die ein massgeblicher Faktor in der Störung der Windheilung darstellt. Der Grund für eine nichtheilende Wunde ist eine Störung des enipfindlichen Gleichgewichts zwischen Wachstumsfaktoren und Entzündungsmediatoren. Wundversorgung soll das Gleichgewicht des Heilungsprozesses wiederherstellen, ohne Zellen zu beschädigen, die zur Wundheilung beitragen. [Knottenbelt, D.C. Equine wound management: are there significant differences in healing at different sites on the body? (Wundversorgung beim Pferd: Sind signifikante Heilungsunterschiede an verschiedenen Körperstellen vorhanden?). Veterinary Dermatology 1997; 8 : 273–290] Résumé Les plaies affectant le tronc cicatrisent rapidement avec une contraction proéminente tandis que les plaies des membres cicatrisent ma1 ou lentement avec une épithélialisation centripète, et souvent avec une contraction insignifiante. Les plaies présentant une granulation chronique exhubérante sur les membres cicatrisent bien après greffe à partir d'un fragment prélevé sur le tronc. Les plaies atones sonl moins fréquentes, mais peuvent présenter un tissu de granulation significatif après application de pansements humides. La transformation en sarcoïde est une cause de plus en plus importante d'échec de cicatrisation. Les transformations en sarcoïdes sur le tronc sont fréquemment verruqueuses, alors que celles localisées sur les membres sont généralement agressives et fibroblastiques. Le but premier du traitement d'une plaie est de promouvoir la progression rapide d'une inflammation aigüe en cicatrisation sans passage par l'inflammation chronique qui est un facteur significatif dans la pathophysiologie de l'échec de cicatrisation des plaies. Les plaies ne cicatrisent pas parce qu'il y a un déséquilibre de la balance délicate entre facteurs de croissance et médiateurs de l'inflammation. Les plaies doivent être traitées de manière à restaurer l'équilibre des processus de cicatrisation sans altération des cellules impliquées dans l'inflammation. [Knottenbelt, D.C. Equine wound management: are there significant differences in healing at different sites on the body? (Traitement des plaies équines: y-a-t-il des différences significatives de cicatrisation en fonction de la topographie corporelle?). Veterinary Dermatology 1997; 8 : 273–290]     

COMPUTED TOMOGRAPHY OF THE PHARYNX IN A CLOSED VS. OPEN MOUTH POSITION

The pharynx is anatomically complex and evaluation can be difficult even with cross‐sectional imaging. Eight animals had computed tomography (CT) studies of the head performed with the mouth open and closed. The studies were anonymized and evaluated by four radiologists for visibility of six anatomic regions (dorsal wall of nasopharynx, lumen of nasopharynx, dorsal margin of the soft palate, ventral margin of the soft palate, oropharynx, and laryngopharynx) and for certainty of a normal or abnormal diagnosis of four different anatomic regions (nasopharynx, soft palate, oropharynx, and laryngopharynx). Mean visual scores differed significantly between mouth positions and were improved when the mouth was open. The ability of radiologists to classify anatomic regions as normal or abnormal vs. unsure also varied between mouth positions, and there was greater uncertainty when the mouth was closed. In addition, estimated volume of the air‐filled nasopharynx differed significantly as a function of mouth position and was greater when the mouth was open (mean=1.187 cm³, SE=0.177) vs. closed (mean=0.584 cm³, SE=0.116). Computed tomographic evaluation of the pharynx can be improved with the mouth open.     

Healing of Canine Autogenous Cancellous Bone Graft Donor Sites

Autogenous cancellous bone was procured from the proximal ends of one humerus and the contralateral tibia of eight adult mixed-breed dogs. Greater weights of bone were consistently harvested from the humerus than from the tibia. Restoration of cancellous bone was more rapid and complete in the humerus than in the tibia. The tibia harvest site filled primarily with fibrous tissue rather than with cancellous bone.     

ASSESSMENT OF A RADIOTHERAPY PATIENT CRANIAL IMMOBILIZATION DEVICE USING DAILY ON-BOARD KILOVOLTAGE IMAGING

The purpose of this study was to utilize state-of-the-art on-board digital kilovoltage (kV) imaging to determine the systematic and random set-up errors of an immobilization device designed for canine and feline cranial radiotherapy treatments. The immobilization device is comprised of a custom made support bridge, bite block, vacuum-based foam mold and a modified thermoplastic mask attached to a commercially available head rest designed for human radiotherapy treatments. The immobilization device was indexed to a Varian exact couch-top designed for image guided radiation therapy (IGRT). Daily orthogonal kV images were compared to Eclipse treatment planning digitally reconstructed radiographs (DRRs). The orthogonal kV images and DRRs were directly compared online utilizing the Varian on-board imaging (OBI) system with set-up corrections immediately and remotely transferred to the treatment couch prior to treatment delivery. Off-line review of 124 patient treatments indicates systematic errors consisting of +0.18 mm vertical, +0.39 mm longitudinal and −0.08 mm lateral. The random errors corresponding to 2 standard deviations (95% CI) consist of 4.02 mm vertical, 2.97 mm longitudinal and 2.53 mm lateral and represent conservative CTV to PTV margins if kV OBI is not available. Use of daily kV OBI along with the cranial immobilization device permits reduction of the CTV to PTV margins to approximately 2.0 mm.     

The disappearance and movement of three triazine herhicides and several of their degradation products in soil under field conditions

Several degradation products of the iriazine herbicides atrazine [2-chloro-4-ethylamino-6-isapropylainino-1,3,5-triazine], cyprazine [2-chloro-4-cyclopropylamino-6-isopropylamino-1,3,5-triazine] and cyanazine [2-chloro-4-(l-cyanomethylethyl-amimo)-6-ethylamino-1,3,5-triazine] were monitored over a 3-year period in soil Trom fields under maiTC production. The soils were predominately loamy sands and sandy clay loams. HydroKy-triazines were determined semi-quanlilatively m the soil samples by gaschromalography, after methylation. Their levels ranged Trom 0.05 to 0.5 ppm. The hydroxy-triazines were the predominant triazine residues in the field during ihe spring and autumn, N-de-ethylated atrazine [2-chloro-4-amino-6-iso-propylamino-1,3,5-triazine] persisted at relatively high levels (0.015–0.02 ppm) 12 months after the application of atrazine. Greater proportions of N-de-ethylated atrazine and cyanazine II [2-chloro-4-(1-carbamoyl-1-methyleihylamino)-6-ethyl-amino-s-iriazine] than of atrazine or cyanazine were found to move through the soil profile into subsurface drainage water (1.2–1.6 m depth). Abbau und Transport von drei Triazin-Herbiziden und einiger ihrer Abbauproduk te im Boden unter Feldhedingungen Boden von Maisfeldern wurde über eine Periode von drei Jahren auf Abbauprodukte folgender Triazin-Herbizide unter-suchi: Atrazin [2-Chlor-4-äthylamino-6-isopropylatnino-1,3,5-triazin], Cyprazin [2-Chlor-4-cyclopropylamino-6-isopropyla-mino-1,3,5-(triazin) und Cyanazin [2-Chlor-4-(1-cyanoinethy-läthylamino)-6-äthylamino-1,3,5-triazin], Bei den Böden han-delie es sich hauptsächlich um lehmige Sande und sandig-tonige Lehme Hydroxy-Triazine wurden in den Bodenproben gas-chromatogruphish nach Methylierung. semi-quantitativ be-stimmt. Ihre Konzeniration im Boden betrug zwischen 0.05 und 0.5 ppm. Die Hydroxy-Triazine waren im Frähjahr und Herbst die vorherrschenden Rücksiände, N-desäthylieries Airazin [2-Chlor-4-amino-6-isopropyIamino-1,1,5-triazin] war zwölf Monate nach der Atrazin-Applikation mit relative hohen Kon-zenirationen(0.015–0.02 ppm) vorhanden. Von N-desäthylier-tem Airazin und Cyanazin II [2-Chlor-4-(1 carbamoyl-1–methy-läthylamino)-6-äthylamino-s-triazin] wurden grössere Anteile im Boden in das unterirdische Drainagewasser transportiert (1.2–1.6 m Tiefe) als es für Atrazin oder Cyanazin der Fs Swiir Disparition et migration dans le sol, au champ, de trois triazines herhicides et de plusieurs de leurs produits de dégradalion. Plusieurs produits de dégradation des triazines herbicides suivantes: atrazine (2-chloro-4-éthylamino-6-isopropylamino-1,3,5-triazine) cyprazine (2chloro-4-cyclopropylamino-6-isopropylamino-l,3,5-triazine) et cyanazine (2-chloro-4 (l-cyanométhyléthylamino)-6-éthylamino-l,3,5-triazine) ont été contrölés dans le sol. pendant une période de trois années, dans des champs de maïs en production, Les sols étaient pour la plupart sablo-limoneux et limono-argilo-sableux, Les hydroxy-triazines ont été déterminées semi-quantalivcmeni dans les échantillons de sols, par chroma tographie gazeuse aprés méthy lation, Leursconcen [rations s'étendaienlde0.05à 0.5ppm, Les hydroxy-triazines ont été les résidus les plus imporiants dans le champ au printemps et à I'aulomne, L'alrazine N-dé-éthylée [2-chloro-4-amino-6-isopropylamino-l.3.5-triazine] a persistéà des concentralions rclativemeni élevées (0.015 à 0.02 ppm) douzemois aprés l'application de l'atrazine, Il a été conslaté que des proportions d'atrazine N-dé-éthylée et de cyanazine II [2-ehloro-4(l-carbamoyl-1-méthyléthylamino)-6-éthylamino-1,3,5-triazine] plus importantes que celles de l'atrazine ou de la cyanazine, migraient à travers le profil du sol. dans la subsurface de drainage dc l'eau (1,2 à 1.6 m de profondeur).