Ultrastructure of sarcocysts from water buffalo in India

The ultrastructure of sarcocysts of macro- and microscopic species of Sarcocystis was compared from naturally infected water buffalo from India. Grossly visible sarcocysts had walls consisting of cauliflower-like villar protrusions, typical of S. fusiformis. The sarcocyst wall of the microscopic species of Sarcocystis was 6.4 microns thick and consisted of tightly packed conical villar protrusions that were 9.6 microns long and 3.7 microns wide at the base. At approximately 3 microns above the base, the distal two-thirds of the villar protrusion became conical shaped and was bent laterally at an angle of 45 degrees to the sarcocyst surface. The granular layer beneath the villar protrusions was 0.9 microns thick. In S. levinei the granular layer was 1.9 microns thick, the villar protrusions were narrow and it had a highly undulating primary cyst wall. Whether the microscopic S. levinei-like sarcocysts of Indian and Malaysian water buffalo are distinct species of Sarcocystis will require further investigation.     

Effect of pelleting and beta-glucanase supplementation on the ileal and fecal digestibility of a barley-based diet in the pig

The influences of pelleting and beta-glucanase supplementation on the digestibility of dietary components in a barley-based diet were investigated in pigs fitted with cannulas in the terminal ileum. The diet contained 49.0% starch, 18.9% crude protein and 14.8% dietary fiber, with arabinoxylans (4.9%), mixed-linked beta-glucans (3.4%) and cellulose (3.3%) as the main fiber components. Pelleting increased mixed-linked beta-glucan solubility from 45 to 62%. Neither treatment influenced the ileal or fecal apparent digestibilities of dry matter (64 and 80%, respectively), energy (62 and 79%), crude protein (53 and 75%), crude fat (26 and 27%) or dietary fiber (58 and 72%). However, pelleting increased (P less than .01) the pre-ileal apparent digestibility of starch from 91.5 to 95.3% and decreased (P less than .03) that of ash from -10 to -23%, while increasing (P less than .005) the fecal apparent digestibility of starch from 98.6 to 99.7%. The solubility of mixed-linked beta-glucans in ileal digesta was lower (P less than .001) in pelleted (26%) than in unpelleted (58%) diets. beta-glucanase supplementation also increased (P less than .05) the ileal apparent digestibility of starch, from 92.6 to 94.3%, and of mixed-linked beta-glucans, from 95.7 to 97.1%. Significant between-pig differences in the apparent digestibility of dietary components were observed. In conclusion, treatments that disrupt the endosperm cell walls in barley can increase the proportion of the diet digested prior to the large intestine.     

Calcium fluxes across the wall of the ovine reticulorumen in vivo

Calcium fluxes were measured, in vivo, in both directions across the ovine reticulorumen wall of four sheep when the luminal potassium concentration was either 30 mmol litre-1 or 90 mmol litre-1. Neither fluxes were affected by an increased potassium concentration although net magnesium absorption was decreased (PO less than 0.05) and the transmural potential difference was increased (P less than 0.01) under these conditions. The results obtained suggest that, unlike magnesium, calcium is transported bidirectionally across ovine ruminal tissue independently of the transmural potential difference across the rumen wall.     

Immunocytochemical study of tissues from clinically normal dogs and of neoplasms, using keratin monoclonal antibodies.

Three commonly used keratin monoclonal antibodies (MAB)--AE1:AE3, CAM 5.2, and MAK-6--were compared with routinely used cytokeratin antibody. The expression of these antibodies was analyzed in several tissues obtained from clinically normal dogs and in a variety of neoplasms from dogs. Using appropriate enzymatic digestion, paraffin-embedded tissues processed in routine manner retained their typical keratin expression. Differentiated and poorly differentiated epithelial neoplasms, lymphomas, and melanomas were studied by use of the avidin-biotin-peroxidase technique. All 4 of the aforementioned antibodies had similar staining profiles. Of 3 anaplastic carcinomas, 2 had positive reaction to all 4 antibodies. All lymphomas, plasma cell tumors, and amelanotic melanomas had negative reaction to MAK-6, CAM 5.2, AE1:AE3, and cytokeratin MAB. Three basal cell epitheliomas had positive reaction to all 4 antibodies, whereas 1 basal cell tumor with a solid pattern had negative staining reaction. Two carcinoids had negative reaction to all markers and 1 of 2 malignant chemodectomas and 1 transitional cell carcinoma had staining reaction to only AE1:AE3 MAB. Comparing the 4 antibodies, use of AE1:AE3 MAB produced the strongest staining intensity followed by cytokeratin, MAK-6, and CAM 5.2 MAB. All 4 antibodies had low background staining. In conclusion, AE1:AE3 and MAK-6 MAB are as useful as cytokeratin MAB for identification of poorly differentiated epithelial neoplasms in dogs and cats.     

Confirmation of rinderpest in experimentally and naturally infected cattle using microtitre techniques

Summary Virulent rinderpest virus was detected by immunoperoxidase staining of microtitre bovine kidney cell cultures within 24 to 48 hours of inoculation with prescapular lymph node and spleen homogenates from experimentally infected steers. Rinderpest virus specific cytopathic effects were evident from 48 hours in microtitre plates and from 72 hours in rolled tube cultures. Nasal and ocular secretions collected from cattle naturally infected with rinderpest and inoculated into bovine kidney cell cultures did not readily yield cytopathic virus in both tubes and microtitre plates, but immunoperoxidase staining of microtitre cultures on the fourth day of inoculation detected replication of virus in cultures inoculated with ocular and nasal secretions from seven of 17 cattle tested.

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Resumen Se detectó el virus virulente de mediante la tinción con inmunoperoxidasa de cultivos de células de ri?ón bovino en bandejas de microtitulación, después de la inoculación de estos con suspensiones homogenizadas de ganglios linfáticos preescapulares y de bazo provenientes de novillos infectados experimentalmente. El efecto citopático del virus de la peste bovina fue evidente desde las 48 horas en bandejas de microtitulación y desde las 72 horas en tubos de cultivo giratorios. Secreciones oculares y nasales colectadas de ganado infectado en forma natural con la peste bovina e inoculadas en cultivos de células de ri?ón bovino, no mostraron efecto citopático fácilmente en tubos giratorios o bandejas de microtitulación, pero la tinción de las bandejas con inmunoperoxidasa reveló replicación del virus a partir del cuarto día de inoculación con secreciones oculares y nasales en siete de los 17 animales examinados.

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Résumé Un virus bovipestique virulent a été décelé par le test de coloration à l'immunoperoxydase de cellules rénales bovines en culture dans des plaques de microtitrage et infectées 48 heures plus t?t avec des homogénats de ganglions lymphatiques et de rate provenant de bouvillons infectés expérimentalement. Les effets cytopathogènes du virus étaient évidents au bout de 48 h dans les plaques de microtitrage et 72 h dans les tubes en rollers. Les sécrétions nasales et oculaires prélevées sur du bétail infecté naturellement par la peste bovine et inoculées sur des cellules rénales bovines n'ont pas toujours montré d'effet cythopathogène aussi bien dans les tubes que dans les plaques de microtitrage. Cependant, la coloration à la peroxydase au jour 4 après l'inoculation a permis de déceler la présence de virus dans 7 cas sur 17.

     

Changes in the MHC Class II+ Dendritic Cell Population of Ovine Skin In Response to Orf Virus Infection

Abstract— Class II+ dendritic cells were widely distributed throughout normal ovine skin in two main locations: a) in or immediately adjacent to the epidermis and epidermal appendages and b) in the vicinity of the blood vessels. They are unlikely to represent a homogeneous population particularly since Langerhans cells, which previously have been found throughout the epidermal appendages, were located only in the epidermis using acetylcholinesterase staining. Following infection with orf virus, a dense mass of closely associated class II+ dendritic cells develops in the exposed necrotising dermis, adjacent to infected hair follicles and under infected degenerating epidermis. These cells interact and appear to form a barrier to invasion, a framework for immune defence and a template for subsequent epidermal repair; they seem to provide the basis of a highly integrated local dermal defence system. Résumé— Des cellules dendritiques de classe II+étaient largement réparties dans la peau ovine normale dans deux principales zones a) dans l'épiderme et les annexes épidermiques ou dans leur voisnage immédiat b) au voisinage des vaisseaux sanguins. Il est peu probable qu'elles représentant une population homogène particulièrement parce que les cellules de Langerhaps, qui ont été découvertes précédemment dans l'ensemble des annexes épidermiques, furent localisées seulement dans l'épiderme en utilisant une coloration à l'acétylcholinesterase. Après une infection par le virus de l'ecthyma, il se forme une masse dense de cellules dendritiques de classe II+étroitement associées, dans le derme nécrotique atteint, adjacente aux follicules pileux infectés et sous l'épiderme dégénératif infecté. Ces cellules interagissent et apparaissent former une barrière à l'invasion, un cadre pour les défenses immunitaires et un patron pour la réparation épidermique ultérieure; elles semblent fournir les bases d'un système de défense dermique local hautement intégré. Zusammenfassung— Klasse II+-Dendritenzellen waren in der gesamten Haut von normalen Schafen in vorwiegend zwei Bereichen verbreitet: a) in oder unmittelbar neben der Epidermis und der epidermalen Anhangsgebiete und b) in dor Nähe dar Blutgefäße. Sie stellen wahrscheinlich keine homogène Population dar, da die Langerhanszellen, die früher übarall in den epidermalen Anhangsgebilden nachgewiesen wurden, bei Acetylcholinesterase-Färbung nur in der Epidermis zu finden waren. Nach einer Orf-Virus-Infektion formiert sich eine dichte Masse aus eng verbundenen Klasse II+-Dendritenzellen in der betroffenen nekrotisierenden Dermis unmittelbar neben den infizierten Haarfollikeln und unter der infizierten, degenerierenden Epidermis. Diese Zellen stehen untereinander in Verbindung und bilden anscheinend eine Barrière gegen die Invasion, ein Gorüst für die Immunabwehr und einen Ausgangs punkt für die anschließenden Reparaturvorgänge in der Epidermis. Sie scheinen als Basis eines hochentwickelten lokalen Abwehrsystems der Haut zu fungieren. Resumen Células dendríticas de class II+ se observaron en gran cantidad en la piel de la oveja especialmente en dos localizaciones: a) en la epidermis, en la dermis muy próxima a la epidermis y en anejos cutáneos y b) en las proximidades de los vasos sanguíneos. No parece tratarse de una población homogénea de células puesto que las células de Langerhans, que previamente se habían encontrado en los anejos epidérmicos, se encontraron únicamente en la epidermis utilizando técnicas de detección del acetilcol-inesterasa. Después de la infección con el virus del ectima contagioso ovino se observó una masa de células dendríticas de clase II, dispuestas de forma muy densa, en las proximidades de la dermis necrosada y de los folículos pilosos y de la epidermis infectada. Eatas células interaccionan entre si y parecen formar una barrera contra la invasión, una red inmunitaria de defensa y participar en la reparación de la epidermis; parece ser que esta población de células dendriticas son la base de un sistema de defensa dérmico local altamente integrado.     

Vitamin deficiencies in cattle

Deficiencies of vitamins A, D, K, E and thiamin can cause severe limitations in beef production. In particular, vitamin A and E can be common causes of lost profit, secondary to limitations of reproductive and growth potential. Prolonged dry periods will reduce available A and E in pasture forage, as can ensiling and prolonged storage of harvested feedstuffs. Polioencephalomalacia is a thiamin responsive disorder, associated with high concentrate feeding and lush pastures. Antimetabolites, such as amprolium, will cause thiamine deficiency when fed in excess. Recent information has shown improved performance with supplemental beta carotene and niacin. The positive responses in reproductive performance, noted with cattle fed supplemental beta carotene, was independent of vitamin A. Supplementation of vitamins above National Research Council recommendations can be justified. However, proper evaluation of feed and animal status, and documentation of a response to supplementation is necessary before diagnosing deficiencies of specific nutrients.