Arthroscopic Study of Cranial Cruciate Ligament and Medial Meniscal Lesions in the Dog

Twenty stifles (10 dogs) were studied for a period of 1 year after various lesions of the cranial cruciate ligament and medial meniscus were produced surgicaoy. Through serial arthroscopic evaluations, degenerative processes In stifles with a "torn" cranial cruciate ligament were documented. Intra-articular changes were minimal after partial meniscectomy and were severe after total meniscectomy. Multiple arthroscopies caused no demonstrable changes.     

CHEMICAL AND BIOLOGICAL PROPERTIES OF TWO NEW HERBICIDES—IOXYNIL AND BROMOXYNIL

Summary. The preparation of ioxynil, bromoxynil, and their salts is described, and information on solubilities and stability to storage is summarized. Although the toxicology of the herbicides is to be reported in greater detail, a preliminary statement is made here. Evidence of herbicidat activity under glasshouse conditions is indicated briefly, and supports the conclusion that both compounds are effective when applied to the foliage of a wide range of dicotyledon weed species. Seedlings of some weed species resistant to the phenoxy alkanoic acids are controlled under glasshouse conditions at doses as low as 0.125 lb/ac, and ioxynil has a wider range of activity than bromoxynil at these low doses. Graminaceous species tolerate 4–8 lb/ac of both herbicides without injury, and certain leguminous crops tolerate one or other herbicide at doses of 0.5–0.75 lb/ac. The contact action of the herbicides is rapid, there are also slower systemic effects, and seed germination is inhibited. In susceptible species the level of post-emergence activity is shown to be influenced by the growth stage of the weed, the distribution of herbicide on the foliage, and environmental factors of which light intensity appears to be most important.
Propriétés chimiques et biologiques de deux nouveaux herbicides: ioxynil et bromoxynil     

Demography and control of Cirsium vulgare (Savi) Ten. in relation to grazing

Cirsium vulgare (Savi) Ten. is a serious biennial alien weed only in pasture land in Australia. To identify reasons for such preferential infestation and to isolate sensitive stages in the life history of C. vulgare, comparative demographic analyses were conducted in grazed, ungrazed and herbicide-treated Mediterranean-like pastures in south-eastern Australia. Grazing by sheep (i) reduced competition from neighbouring plants, (ii) increased C. vulgare growth, flowering and seed (achene) production, and (iii) promoted survival of C. vulgare seedlings. The most sensitive period in the life of C. vulgare appears to be the transition from the seedling to rosette life stages where, for example, an average survival rate of only 0.2 and 1.0% occurred in ungrazed and grazed pastures, respectively. In contrast, 10 and 15% of seeds successfully emerge on average as seedlings, and 49 and 51% of rosettes successfully develop into adult plants. Control of C. vulgare with dicamba was most effective just after initiation of autumn rainfall. This time corresponds to the period of naturally high seedling mortality in C. vulgare induced by competition from neighbouring plants. Démographie de Cirsium vulgare (Savi) Ten. et sa maîtrise par rapport au pâturage Cirsium vulgare (Savi) Ten. est une mauvaise herbe bisannuelle en Australie, d'origine étrangère, mais elle n'est importante que dans les pâtures. Dans le but de déterminer les raisons de cette préférence et d'établier les stades sensibles dans le cycle de C. vulgare, des analyses démographiques ont été entreprises au sud-est de l'Australie dans des pâtures de type méditerranéen. Le pâturage des moutons a diminué la concurrence des plantes voisines, rendu plus importantes la croissance de C. vulgare ainsi que sa floraison et la production de graines (akènes) et favorisé la survie des jeunes plants adventices. Il parait que le stade le plus sensible de la vie de C. vulgare est la période de transition du stade jeune plant au stade rosette, où le taux moyen de survie était de 0,2% sans et 1% avec pâturage. Par contre, une levée de 10 et 15% des graines a été constatée et 49 et 51% des rosettes deviennent des plantes adultes. Le dicamba s'est montré le plus efficace contre C. vulgare en application juste après le commencement des pluies d'automne, époque d'une forte mortalité naturelle parmi les jeunes plants, provoquée par la concurrence des plantes voisines. Populationsdynamik und Bekämpfung von Cirsium vulgare (Savi) Ten. unter Bezug auf Beweidung Cirsium vulgare tritt in Australien nur in Weideland als wichtiges, zweijähriges, adventives Unkraut auf. Um Ursachen für die selektive Besiedelung von Grasland und um empfindliche Entwicklungsstadien im Entwicklungszyklus herauszufinden, wurden in SO-Australien vergleichende populationsdynamische Untersuchungen in beweidetem, unbeweidetem und mit Herbiziden behandeltem Grasland von mediterranem Typus durchgeführt. Die Beweidung durch Schafe hatte zur Folge, dass (i) die Konkurrenz durh benachbarte Pflanzen verringert, (ii) das Wachstum, Blühen und die Samenproduktion von C. vulgare gesteigert und (iii) die Ueberlebensrate von C. vulgare-Sämlingen erhöht wurden. Es scheint, dass im Entwicklungszyklus von C. vulgare der Uebergang vom Sämlings-zum Rosettenstadium die empfindlichste Phase darstellt, in der nur 0,2% in unbeweidetem. resp.1% in beweidetem Grasland überleben. Die Keimungsrate hingegen beträgt im Mittel 10 und 15% und 49 und 51% der Jungpflanzen im Rosettenstadium entwickeln sich zu adulten Exemplaren. Die Bekämpfung von C. vulgare mit Dicamba erwies sieh kurz nach Beginn der herbstlichen Regenfälle als am wirksamsten. Dieser Zeitpunkt entspricht einer Periode erhöhter, natürlicher Keimlingsmortalität, bedingt durch eine verstärkte Konkurrenzierung durch benachbarte Pflanzen.     

Diaphragmatic hernia. Analysis of fifty-six cases in dogs and cats

A review of fifty-six cases of diaphragmatic hernia in the dog and cat is presented. These were admitted to the University of Glasgow Veterinary School between January 1972 and August 1978. Fifty-three of these cases were treated surgically but only twenty-nine survived to be discharged from the hospital. The reasons for the low survival rate are discussed in detail.     

EVALUATION OF 99MTC-DIETHYLENETRIAMINEPENTAACETIC ACID RENAL SCINTIGRAM CURVES IN NORMAL DOGS AFTER INDUCTION OF DIURESIS

The normal 99mTc-diethylenetriaminepentaacetic acid (DTPA) renal scintigram curve has 3 distinct phases; an arterial phase followed by progressive uptake and subsequent excretion from the kidney. In dogs with X-linked hereditary nephritis, a distinct flattening of the renal scintigram curve has been observed prior to any decline in glomerular filtration rate (GFR). The cause of this shape change is not known, however, it coincided with decreased urine-specific gravity and thus might be related to polyuria. To further evaluate this possibility, we assessed whether diuresis without concurrent renal disease could flatten the 99mTc-DTPA renal scintigram curve. GFR scintigraphy was performed in six healthy dogs once as a baseline, and again after induction of diuresis by each of four different methods. Scintigram curves were evaluated subjectively as well as quantitatively by calculation of GFR estimates, mean renal transit times, time to peak activity and half-time clearance. Complete flattening of the renal scintigram curve did not occur with diuresis alone, and therefore, flattening of the scintigram curve may serve as an early indicator of renal dysfunction. However, during diuresis after intravenous saline administration, alterations in time to peak activity and mean renal transit time may create inaccuracies in GFR estimates based on the conventional regression formula that cause a false lowering of the resultant global GFR value.     

Establishing climate–growth relationships for yelloweye rockfish (Sebastes ruberrimus) in the northeast Pacific using a dendrochronological approach

We applied dendrochronology (tree‐ring) methods to develop multidecadal growth chronologies from the increment widths of yelloweye rockfish (Sebastes ruberrimus) otoliths. Chronologies were developed for the central California coast, a site just north of Vancouver Island, British Columbia, and at Bowie Seamount west of the Queen Charlotte Islands, British Columbia. At each site, synchronous growth patterns were matched among otoliths via the process of cross‐dating, ensuring that the correct calendar year was assigned to all increments. Each time series of growth‐increment measurements was divided by the values predicted by a best‐fit negative exponential function, thereby removing age‐related trends. These detrended time series were averaged into a master chronology for each site, and chronologies were correlated with monthly averages of sea surface temperatures, upwelling, the Northern Oscillation Index, and the Pacific Decadal Oscillation. The two northern growth chronologies positively correlated with indices of warm ocean conditions, especially from the prior summer through the spring of the current year. During the same period, the California chronology positively correlated with indices of cool ocean conditions, indicating an opposing productivity regime for yelloweye rockfish between the California Current and the Gulf of Alaska. Overall, this study demonstrates how tree‐ring techniques can be applied to quickly develop annually resolved chronologies and establish climate–growth relationships across various temporal and spatial scales.     

Distribution of oxytetracycline into ocular tissues and tears of calves

A long-acting oxytetracycline formulation was administered (20 mg/kg of body weight) intramuscularly to calves, and the concentrations of the drug in serum, ocular tissues and tears were measured. The drug was distributed selectively to the epithelium of the conjunctiva and to the lacrimal gland ductules, and reached concentrations in each tissue that exceeded those in serum. The drug did not penetrate into the aqueous humour, and produced mean peak lacrimal fluid concentrations less than 1 microgram/ml after i.m. administration. When given subconjunctivally, however, concentrations greater than 2.0 micrograms/ml were observed in tears for 72 h. Severe local reactions occurred in all calves that were given the drug subconjunctivally.