Occlusion of the Middle Cerebral Artery: a New Method of Focal Cerebral Ischemia in Rats

The study in Wistar rats attempted to improve the occlusion technique of the middle cerebral artery (MCA) as a precise method for initiating stroke. In a first part it was necessary to study the exact anatomy of blood vessels of the brain in seven rats of 170-410 g body weight by corrosion cast. The lengths and diameters of defined locations of the blood vessels were measured. The temporary as well as the permanent methods were refined or replaced. The first one was completed in main training the physiological blood flow after temporary occlusion, while the permanent occlusion was performed by positioning a silicone cap in the MCA. A filament guide was introduced from the common carotid artery (CCA) via internal carotid artery (ICA) to guide the silicon cap at the branch of the MCA. Histological sections of the brain of rats showed 24 h after the permanent occlusion a reproducible infarct in the brain. This area corresponded very well with the supply of the MCA. The new occlusion method with a silicon cap was compared with the occlusion methods of CCA route and external carotid artery (ECA) route. The total infarct volume was significantly larger in the CCA route and ECA route groups than in the silicon cap group (means: CCA route 261 mm³; ECA route 191 mm³ vs. 128 mm³ silicon cap group; P  < 0,05). It could be demonstrated that the new silicon cap occlusion technique imitates the pathological situation of a cerebral infarct in man. Moreover it is less invasive for the animals and more precise and reproducible regarding the infarcted area in comparison to the other occlusion methods. Based on anatomical measurements of the blood vessels the described silicon cap method can be recommended for rats of a body weight between 340–370 g.     

USE OF COMPUTED TOMOGRAPHY AND RADIOLABELED LEUKOCYTES IN A CAT WITH PANCREATITIS

The normal feline pancreas has been evaluated using radiolabeled leukocytes (99mTc-HMPAO) and computed tomography. The purpose of this report is to describe a clinical case where both modalities were utilized to assess the inflamed feline pancreas. A nine year old female cat presented with anorexia, depression and some vomiting. Blood values were unremarkable. Radiographs and ultrasound were suggestive of pancreatitis. The cat's leukocytes were separated and labeled according to an established protocol. Whole body images were acquired immediately, at 5 and 30 min, and at 1, 2, 4, and 17 hours post injection. Approximately 48 h later, the animal was anesthetized and computed tomography of the abdomen was preformed both pre and post contrast. Surgical biopsies were taken. The distribution of the WBCs was similar to that documented in normal animals, however, at 2 h there was faint uptake seen in the region of the pancreas. This uptake became more intense at 4 h and persisted at 17 h. Computed tomography showed irregular margination of the pancreas, it was larger than normal and inhomogeneous. Contrast enhancement was inhomogeneous and its peak enhancement was not reached until 10 min post injection; normal feline pancreas enhances homogeneously and peaks immediately. Histopathology confirmed pancreatitis with lymphocytic, plasmacytic, neutrophilic and eosinophilic inflammation and fibrosis. Radiolabeled leukocytes can be used to document pancreatic inflammation and this is best seen 4 h after injection. Computed tomography allows superior visualization of the pancreas. Both the appearance and contrast enhancement pattern of the inflamed pancreas differ from normal.     

Evaluation of the agar-gel immunodiffusion test in the diagnosis of canine blastomycosis

The agar-gel immunodiffusion test was used to evaluated 35 dogs with histopathologically confirmed blastomycosis and 98 dogs without blastomycosis. The test had a sensitivity of 91% and a specificity of 96%. Thirteen of the dogs treated for blastomycosis were tested at 6 to 33 months after treatment with amphotericin B. Ten of 13 dogs became seronegative and 3, though clinically normal, remained seropositive at 19, 20, and 20 months, respectively, after amphotericin treatment.     

Nitrat und Nitrit in der Tierernährung

Summary A review is given about publications of the last 30 years, concerning problems of high nitrate content of feeds. Nearly 10 areas of scientific work can be discerned. The most important of them have to do with: Analysis of nitrate and nitrite; danger of poisoning by feeds and water rich in nitrate; physiological and pathological consequences of high doses of nitrate or nitrite; reduction of nitrate (in the rumen and in the fermentation of plants) to nitrite, hydroxylamine and ammonia; behaviour of nitrate in the process of silage making; adverse effects upon the functions of the thyroid gland by nitrite and the disturbances of the availability of vitamin A and vitamin E by nitrate-nitrite.

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Résumé On a donné un rapport sur les travaux scientifiques publiés dans les dernières trente années, concernant les problèmes d'une teneur haute en nitrate dans les fourrages. On peut discerner à peu près dix régions de travail scientifique. Les plus importantes sont: analyses du nitrate et du nitrite; le danger des intoxications par les fourrages et par l'eau, qui sont riches de nitrate; les conséquences physiologiques et pathologiques des doses hautes du nitrate ou du nitrite; la réduction du nitrate (dans le panse des ruminants et dans les fourrages en fermentation) au nitrite, au hydroxylamine et à l'ammonique; les réactions du nitrate pendant la préparation des silages; les influences défavorables aux fonctions de la glande thyroide par le nitrite; et les actions de déranger l'utilisation de la vitamine A et de la vitamine E par nitrate-nitrite.

     

Repetitive Applications of the Biocontrol Agent Pseudomonas putida 06909-rif/nal and Effects on Populations of Phytophthora parasitica in Citrus Orchards

ABSTRACT Pseudomonas putida 06909-rif/nal was applied repetitively during the irrigation season in two citrus orchards over 3 years. In a mature (50-yearold) commercial citrus orchard covering 2.02 ha, weekly applications of Pseudomonas putida 06909-rif/nal with an in-field fermentor resulted in soil populations that fluctuated between 2.83 log CFU + 1 per g of soil and 4.35 log CFU + 1 per g of soil. Resulting rhizosphere populations of Phytophthora parasitica were significantly reduced in 1999 but not 1997 or 1998. In a newly planted citrus orchard, yearly applications of Pseudomonas putida 06909-rif/nal at the beginning of the irrigation season resulted in high soil populations of Pseudomonas putida 06909-rif/nal that declined rapidly and never reduced the rhizosphere populations of Phytophthora parasitica. When Pseudomonas putida 06909-rif/nal was applied weekly, soil populations increased throughout the 1997 and 1998 irrigation seasons, reaching a maximum in 1998 and remained high throughout the 1999 irrigation season. Rhizosphere populations of Phytophthora parasitica were significantly reduced in 1998. Yearly applications of the fungicide metalaxyl and the nematicide phenamiphos reduced rhizosphere populations of Phytophthora parasitica in 1997 but not in 1998 or 1999. Pseudomonas putida 06909-rif/nal was uniformly distributed throughout the soil profile to a depth of 75 cm in both yearly and weekly applications. When applied through low-volume minisprinklers, Pseudomonas putida 06909-rif/nal was found in aerosols up to 3 m away.     

Physiological influences on wood-destroying insects of wood compounds and substances produced by microorganisms

Summary Wood-destroying insects react to and depend regarding their nutrition on compounds contained in wood or produced by microorganisms in wood. This relation is a complex matter in the biology of the insects and the chemistry of wood and of the metabolism of woodinhabiting microorganisms. Results on the reaction of Coleoptera and Isoptera to attractive or repellent compounds in wood species or substances produced by fungi in wood are reviewed with emphasis to differences among various insect species. Nutrition of wood-destroying insects depends on nitrogen compounds of the wood; the content of nitrogen can be increased by the presence of fungi. Existing results on the relation between microorganisms and insects are also summarized including toxicity or parasitic influence of part of the microorganisms on insects. The survey may stimulate further investigations which are necessary for better knowledge of the complex interrelations.Prepared for the Convention of the International Academy of Wood Science at Raleigh (S.-Carol., USA) in March 1971.