Prevalence of ophthalmic disease in blue‐eyed horses

A perception exists amongst referring veterinarians and the lay public that blue‐eyed horses have increased frequency of ocular disease. The aim of this retrospective study was to assess the prevalence of ocular disease in horses with blue or heterochromic eyes relative to those with brown eyes. The medical records of horses presenting to either the Comparative Ophthalmology services or Equine Medicine/Surgery services at 2 institutions were reviewed. Signalment, ocular and nonocular diagnoses were recorded. Ocular disease was divided into 4 categories: adnexa, cornea, intraocular/orbit and squamous cell carcinoma (SCC). Owners were contacted by telephone to confirm iris colour. Chi‐square analysis was used to compare group proportions. A total of 164 eyes of horses with ocular disease and 212 eyes of horses without ocular disease were included. Blue eyes were equally common in the ocular disease and nonocular disease groups (P = 0.265). There was no significant difference in the proportion of blue‐ and brown‐eyed horses when comparing the adnexal and corneal (P = 0.548), corneal and intraocular/orbit (P = 0.379) and adnexal and intraocular/orbit (P = 0.843) categories. A significant difference was detected in the proportion of blue‐eyed horses between the adnexal (P = 0.000), corneal (P = 0.033), intraocular/orbital (P = 0.000) and SCC categories, with a higher proportion of blue‐eyed horses in the SCC than in the other 3 groups. Horses with blue or heterochromic irides are more likely to develop ocular SCC than horses with brown irides, but are not more likely to have adnexal, corneal or intraocular/orbital disease or to be presented for evaluation of ophthalmic disease. Veterinarians should consider the results of this study when answering questions from the lay public regarding the predisposition of blue‐eyed horses to ocular disease.     

An enzyme-linked immunosorbent assay for the detection of antibody against avian influenza virus

An enzyme-linked immunosorbent assay (ELISA) was developed for detecting antibody to type A avian influenza (AI) virus. The sensitivity and group specificity of the AI-ELISA were compared with those of the agar-gel-precipitin test (AGPT) and the hemagglutination-inhibition (HI) test under conditions of both controlled and field exposure. During the course of temporal experimental infection (0-76 days) of specific-pathogen-free (SPF) chickens with AI subtype Hav9N2, the AI-ELISA was able to detect specific AI antibody as early as 8 days postinoculation (PI), and it measured rising levels of antibody through 35 days PI, at which time the chickens were re-exposed to AI virus. Conversely, AGP tests were negative through 35 days PI, and HI tests began to detect low levels of AI antibody only at 21 days PI. Following a secondary infection at 35 days PI with the same AI subtype, all tests measured rising levels of AI-specific antibody (35-76 days PI). However, the AGP test was positive at only the 7- and 14-day samplings postsecondary immunization. Under field conditions, the AI-ELISA was able to detect serum AI antibody in flocks from which highly pathogenic AI was isolated, but the AGP tests of these sera were negative.     

水稻土的力学性质与水分含量的关系

土壤的抗剪强度和抗压强度以及变形性质是决定耕作阻力、机具的通行性能及耕作质量的重要因素,也是机具正确设计所必须考虑的因素。过去对于耕作土壤的强度研究,多从旱地的松散状况出发,把土体的粘结只归因于水膜的表面张力和水膜的数量,并得出结论:土壤强度与含水量呈抛物线关系。对于搅动后土壤粘结的机制,认为包括水膜粘结和分子引力粘结两种^[1]。最近山中金次郎指出^[2],在这二种不同粘结机制的转折处有明显的破折现象,但对水稻土的情况研究极少。     

Callus induction and plant regeneration from cotyledonary explants of ash gourd (Benincasa hispida L.)

A protocol for the production of complete plantlets through multiple shoots from the cotyledon-derived calli of ash gourd (Benincasa hispida L.) is described. The embryos were excised from mature seeds and cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurin (BAP, 1–5 μM). After 10 days the well-developed green cotyledons from the growing embryos were isolated and cultured on MS medium fortified with 2,4-D (1–6 μM). The cultured cotyledons gave rise to luxuriantly growing calli after 6 weeks. These calli were subcultured on MS medium supplemented with various concentrations of BAP (1–6 μM) alone or in combination with naphthalene acetic acid (NAA, 0.2 and 0.5 μM) for regeneration. The regenerated shoots were multiplied and rooted on quarter strength MS medium supplemented with indole-3-butyric acid or NAA (1–5 μM). The rooted shoots were transplanted to soil with 90% success.     

Lesions of the enteric nervous system and the possible role of mast cells in the pathogenic mechanisms of migration of schistosome eggs in the small intestine of cattle during Schistosoma bovis infection

The enteric nervous system in the small intestine of cattle during Schistosoma bovis infection was studied by histological stains and immunohistochemical methods. Lesions due to migration of schistosoma eggs were located mainly in the mucous and the submucous layer overlaying the submucous vascular arcades. Granulomas destroyed ganglia, neurons, nerves fibre strands and nerve fibres. Ganglia situated within or near granulomas were infiltrated by mast cells, eosinophils, lymphocytes, globule leukocytes, neutrophils and macrophages. Mast cells were in close contact with degenerating neuronal perikarya. Whereas vasoactive intestinal peptide-like immunoreactivity in the nerves and neurons in the ganglia within and around granulomas was increased, the neurofilament-like immunoreactivity was reduced. Compared to the myenteric and external submucous plexuses, the internal submucous and mucous plexuses were the most damaged. These changes imply reduced functional capacity in the nervous tissue which might cause reduced motility, malabsorption and partly account for the loss of body weight and condition and failure to thrive which occur in schistosomosis.Biotinylated affinity purified swine anti-rabbit and mouse anti-rabbit immunoglobulins reacted nonspecifically with a subset of mast cells. The reaction revealed many mast cells in early forming granulomas and around schistosome egg tracts and infiltration of mast cells into the ganglia of intestinal nerve plexuses. The observation shows a localized, Type I hypersensitivity reaction suggesting for the release of mast cell-derived chemical mediators in the intestinal reaction to trap or evict S. bovis eggs and to cause diarrhoea.     

Formation of mixed invasions of waterfowl

It is established that wild and synanthropic waterfowl of the order Anseriformes (gadwell, mallard, graylag goose, teal, garganey, etc.) are possible sources of mixed invasions i.e., an etiological factor in forming and maintaining ill-being of domestic geese with respect to the following diseases: echinostomatidosis, amidostomosis, ganguleterikidosis, thominxosis, streptocarosis, echinuriosis, as well as ectoparasites (bird lice).     

Changes in mass and chemical composition of grass roots during decomposition

The decomposition of dead roots of perennial grasses was examined in nylon litter bags not containing soil at two soil depths, 10 and 20 cm, and also in larger nylon bags containing soil at 020 cm depth. Bags were sampled three times during the growing season to determine weights of organic matter, crude protein, Klason lignin and non-structural and structural carbohydrates.
From 3 July to 5 October (94 days) the litter bags at 10 and 20 cm and the nylon bags lost, respectively, 35,38 and 65% of their organic mass of particle size < 1 mm.
Non-structural carbohydrates constituted 6% of the organic matter in the original sample but only 1% or less during the sampling period. Klason lignin increased from 22 to 29% and crude protein from 8 to 10% of the remaining organic matter, whereas structural carbohydrates changed very little.
The constituents were degraded at different rates. The non-structural carbohydrates had decomposed almost completely by the first sampling and of the other constituents the structural carbohydrates were degraded most rapidly. Before the first sampling unexpected amounts of structural carbohydrates, particularly glucans, had disappeared.
The results help to explain rapid declines in root mass (up to 50%) during summer in perennial grass leys observed in earlier experiments.     

Seed potato production in Northern Ireland

Summary With cool moist summer weather, Northern Ireland is suited for the production of vigorus healthy potato stocks. An export trade to Great Britain and countries in Europe, Asia and Africa has been developed during the last twenty years. As a result of research, particularly in plant pathology and nematology, and with the co-operation of both farmer and merchant methods have been developed to ensure that healthy stocks are propagated on land known to be free from potato root eelworm.

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Zusammenfassung Der kühle, feuchte Sommer Nordirlands begünstigt die Erzeugung kr?ftiger, gesunder Kartoffelbest?nde. Die Pflanzguterzeugung hat seit der Vorkriegszeit einen betr?chtlichen Aufschwung erfahren und in den letzten Jahren wurden j?hrlich nahezu 50 000 1 Saatkartoffeln nach Grossbritannien und eine gleiche Menge nach L?ndern in Europa, Asien und Afrika geliefert. Die Forschungsarbeiten auf dem Gebiet der Pflanzenpathologie werden besprochen. Die Züchtung erfolgt sowohl durch den Staat wie durch einen Privatzüchter, und viele der zur Zeit in Grossbritannien angebauten Sorten sind in Nordirland erzeugt worden. Die Verbreitung des Wurzel?lchens aus einigen wenigen befallenen G?rten und Feldern ist durch gesetzliche Massnahmen verhütet worden und die Züchtung nematodenfreier Sorten wird in die Hand genommen. Der gute Ruf, dessen sich das Pflanzgut aus Nordirland erfreut, ist mit der engen Zusammenarbeit der Forschungs- und Beratungsstellen des Ministeriums für Landwirtschaft mit Landwirt und H?ndler zu verdanken.

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Résumé Le temps d'été frais et humide de l'Irlande du Nord est favorable à la production de cultures saines et vigoureuses de pommes de terre. La production de plants a considérablement augmenté depui l'avant-guerre et des dernières années près de 50.000 tonnes de plants de pomme de terre ont été expédiées chaque année vers la Grande-Bretagne et une même quantité vers différents pays d'Europe, d'Asie et d'Afrique. Les recherches dans le domaine de la pathologie végétale, concernant entre autres les méthodes de lutte contre les malladies des tubercules et le mildiou, ainsi que la sélection et la multiplication de cultures exemptes de virus, sont discutées. Les travaux de sélection sont exécutés par le gouvernement et par un cultivateur privé; de nombreuses nouvelles variétés cultivées actuellement en Grande-Bretagne proviennent de l'Irlande du Nord. La propagation du nématode doré à partir d'un petit nombre de jardins et de champs infectés a été enrayéc par la législation et I'on s'occupe de la sélection de variétés résistantes aux nématodes. La renomméc des plants de pomme de terre de I'Irlande du Nord est due à l'étroite coopération des services de recherches et d'information du Ministère de l'Agriculture avec les cultivateurs aussi bien qu'avec le commerce.

     

A quick microtechnique for inspection of potato periderm or wound periderm formation

Summary A method for a quick inspection of wound periderm formation is described. Sections are freehand cut into a stain solution, and microscopic examination is accomplished with an epiplanatic lens.