Twenty-four dogs with a parasitologically and serologically established diagnosis of leishmaniasis were studied to investigate the atrophy of the masticatory muscles which commonly occurs in this disease, and to compare the lesions in the masticatory muscles with those in the cranial tibial muscles. The 24 animals were divided into three groups of eight, group A dogs with no muscular atrophy, group B dogs with different degrees of atrophy in the masticatory and skeletal muscles, and group C dogs with similar degrees of atrophy in the masticatory and skeletal muscles. Increased activities of creatine phosphokinase and lactate dehydrogenase were recorded in only some of the dogs in groups B and C, but there were no significant differences between the mean activities in the three groups. Electromyographic changes indicating myopathy and involving both the temporalis and cranial tibial muscles, were observed in two of the dogs in group A, seven of those in group B, and in all the dogs in group C. Muscle histopathology revealed a variable degree of muscle fibre necrosis and atrophy, mononuclear infiltrates and neutrophilic vasculitis in all the dogs except two in group A. Leishmanial amastigotes were found within macrophages and myofibres in 16 of the dogs, some in each group. IgG immune complexes were detected in muscle samples, and circulating antibodies against myofibres were detected in serum samples from all the 24 dogs.

A conventional nonmutant animal that could be experimentally infected with Helicobacter pylori isolates would be a useful animal model for human H. pylori-associated gastritis. Gnotobiotic and barrier-born pigs are susceptible to H. pylori infection, but attempts to infect conventional pigs with this bacterium have been unsuccessful. In the present study, a litter of eight 20-day-old crossbreed piglets were purchased from a commercial farm. Six of them were orally challenged two to five times at different ages, between 29 and 49 days, with doses of H. pylori inoculum containing approximately 10(9) bacterial cells. Two animals served as controls. The inoculation program began 2 days postweaning when the piglets were 29 days of age. Prior to every inoculation, the piglets were fasted and pretreated with cimetidine, and prior to the first and second inoculation each piglet also was pretreated with dexamethasone. The challenged piglets were euthanasized between 36 and 76 days of age. H. pylori colonized all six inoculated piglets. The pathology of the experimentally induced gastritis was examined macroscopically and by light and electron microscopy. H. pylori induced a severe lymphocytic gastritis in the conventional piglets and reproduced the large majority of the pathologic features of the human disease. Therefore, the conventional piglet represents a promising new model for study of the various pathogenic mechanisms involved in the development of lesions of the human H. pylori-associated gastritis.

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Summary The columnar cells of the equine cecum and great colon contain secretory granules between 0.13 and 0.40 μ in diameter. The arrangement of these granules at the apex of the columnar cells presents a peculiarity offering an explanation for the appearance, when viewed through the light microscope, of three zones of cytoplasm at the cell's apex. In contrast, no zonation is observed in the columnar cells of the glandular epithelium, because the entire apex of these cells is filled with secretory granules. Taking into consideration the structure of the granules as well as their electron density and histochemical reactions, it is suggested that they are probably mucous in nature. On the other hand the manner in which they are secreted offers the opinion that it is merocrine. Zusammenfassung Sekretgranula im Säulenepithel des Blinddarms und großen Kolons beim Pferd Die Sekretgranula in den prismatischen Epithelzellen des Blinddarms und grofien Kolons beim Pferd haben einen Durchmesser von 0,13 bis 0,40 μ. Ihre elektronenoptisch sichtbare Anordnung am Apex der Zellen bietet eine Besonderheit dar, die jene 3 Zonen des Zytoplasmas erklärt, die man lichtmikroskopisch beobachtet. Im Gegensatz dazu zeigt das Zytoplasma des Drüsenepithels keinerlei zonale Gliederung, da der gesamte Apex dieser Zellen mit Sekretgranula angefüllt ist. Die Struktur der Granula, ihre Elektronendichte und ihre histochemischen Reaktionen sprechen dafür, daß es sich wahrscheinlich um Schleimgranula handelt. Andererseits weist die Art ihrer Absonderung auf eine merokrine Sekretion hin.

Résumé L'étude du plexus pelvien et de ses branches afférentes est basée sur l'examen de ces éléments chez quatre chevaux, deux mâles et deux femelles. Au point de vue macroscopique, les nerfs splanchniques sacrés n'ont été rencontrés que dans un seul cas. L'examen des fibres myélinisées a été effectué par la technique de coloration selon Landau‐Ignesti. Les observations microscopiques se revelent que des fibres sensitives sont disseminées parmi les fibres myélinisées du nerf hypogastrique. La structure des ganglions du plexus et de leurs cellules, étudiée par la technique de Marsland‐Glees et Erikson, n'a pas montré de particularité remarquable. Zusammenfassung Beitrag zum Studium des Plexus pelvinus beim Pferd Der Plexus pelvinus und seine AfTerenzen wurden an je 2 Hengsten und Stuten untersucht. Makroskopisch wurden die Nervi splanchnici sacrales nur in einem Fall gefunden. Die myelinisierten Nervenfasern wurden nach Landau‐Ignesti gefärbt. Mikroskopisch ergab sich, daß die sensiblen Fasern sich unter den myelinisierten Fasern des N. hypogastricus befinden. Die Struktur der Ganglien des Plexus und ihrer Zellen, die nach Marsland‐Glees und Erikson behandelt wurden, ergab keine Besonderheiten. Summary Contribution to the Study of the Plexus pelvinus of the Horse The plexus pelvinus and its roots were studied in two stallions and two mares. Nn. splanchnici sacrales were found macroscopically in only one case. The myelinated fibers were stained using the Landau‐Ignestis method. Microscopic examination showed that the sensory fibers were among the myelinated fibers of the N. hypogastricus. The ganglia of the plexus pelvinus, trated according to the Marsland‐Glees‐Erikson method, showed no special features. Resumen Contributión al estudio del plexo pelviano en el caballo El plexo pelviano (Plexus pelvinus) y sus aferentes se investigaron en dos caballos y en dos yeguas. Macroscopicamente, los nervios esplácnicos sacros (Nervi splanchnici sacrales) sólo se encontraron en un caso. Las fibras mielínicas se colorearon según Landau‐Ignesti. El estudio microscopico demostró, que las fibras sensitivas se encuentran entre las fibras mielínicas del N. hipogástrico. La estructura de los ganglios del plexo y de sus células, tratadas según Marsland‐Glees y Erikson, no presentó detalles particulares.

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Summary The author studied the enterochromaffin cells in the surface and glandular epithelium of the large intestine of the horse. The methods used are the Gomori hexamin silver‐nitrate (argentaffin) and the methods of Bodian (1936) and Singh (1964) (argyrophile). These two silver‐nitrate impregnation methods, showed that the enterochromaffin cells are intra‐epithelial and are distinguishable among the two other kinds of cells (cylindrical and goblet) in the glandular and surface epithelium. They were more frequent at the fundus of the intestinal crypts than in the body and neck (in all parts of the large intestine), and less numerous in the surface epithelium. In a more detailed study of these intra‐epithelial enterochromaffin cells, based on the reaction of the silver‐nitrate impregnation methods, four types of cells were distinguished, dependent on the non‐immutable character of the cytoplasmic granules. Zusammenfassung Die enterochromaffinen Zellen des Oberflächen‐ und Drüsenepithels des Dickdarmes des Pferdes Zur Darstellung der chromaffinen Zellen diente die Gomorische Silbernitrat‐Imprägnation nach Bodian (1936) und Singh (1964). Diese beiden Silber‐Imprägnationsmethoden zeigten, daß die enterochromaffinen Zellen intraepithelial liegen und von den übrigen Zellen (Zylinder‐ u. Becherzellen) des Oberflächen‐ und Drüsenepithels unterscheidbar sind. In allen Teilen des Dickdarms treten die chromaffinen Zellen im Fundusgebiet der intestinalen Krypten häufiger auf als im Gebiet des Körpers und des Halses. Im Oberflächenepithel sind sie jedoch weniger zahlreich. Die Silber‐Imprägnations‐Methode läßk auf Grund der Unveränderlichkeit der zytoplasmatischen Granula vier Zelltypen unterscheiden. Résumé les cellules entérochromaffines de l'épithélium superficiel et glandulaire du gros intestin chez le cheval l'auteur étudie les cellules entérochromaffines de l'épithélium superficiel et glandulaire du gros intestin chez le cheval. on emploie les méthodes au nitrate d'argent‐hexamine gomori (argentaffinè) et les méthodes de bodian (1936) et Singh (1964) (argyrophile). Ces deux méthodes d'imprégnation au nitrate d'argent montrent que les cellules entérochromaffines sont intra‐épithéliales et se distinguent des deux autres espèces de cellules (cylindriques et caliciformes) dans l'épithélium glandulaire et superficiel. Elles sont plus fréquentes au fond des cryptes intestinales que dans le corps et le col (dans toutes les parties du gros intestin) et moins nombreuses dans l'épithélium superficiel. Dans une étude plus détaillée de ces cellules enterochromoffines intraépithéliales, basée sur leur réaction aux méthodes d'imprégnation au nitrate d'argent, on différencie quatre types de cellules, selon le caractère des granules cytoplasmiques. Resumen Las células enterocromafines de los epitelios superficial y glandular del intestino grueso del caballo El autor estudia las células enterocromafines en los epitelios superficial y glandular del intestino grueso del caballo. Las técnicas empleadas son la de la hexamina‐nitrato de pl...

Bovine Spongiform Encephalopathy (BSE) is a transmissible degenerative disease of the central nervous system. It belongs to a group of diseases which affect man and various kinds of animals and they have a similar histopathological appearance. The harmful agent of BSE and all the others spongiform encephalopathies have not been totally clarified. Today according to the predominant opinion this agent is consisted mainly or/and only of an abnormal protein, which is called prion. In various observations the harmful agent appears like proteinaceous cylinders which are consisted of aggregations or polymerized forms of the agent and it is called prion-protein (PrP). It has been proved that there are two isoforms of PrP. The first of them, called PrPc, is produced from many cells of man and animals and consists a cellular structural element. The second, called PrPs t, due to its specific properties, it is considered to be pathological and responsible for the spongiform encephalopathies. The replication of PrPsc seems to take place in the lysosomes of central nervous system cells, dendritic, and other reticular cells of the lymphatic organs through transformation of PrPc into PrPsc. It appears BSE caused by feeding meat and bone meals to cattle which were originated from scrapie infected sheep. Refering to the pathogenesis originating from experimental data it seems that initially the PrF* enters the body by food and afterwards is settled in various lymphoid organs where the first replication takes place. It is believed that BSE is transmitted through the nerves to the CNS, where it creates the characteristic lesions of vacuolar degeneration of the neurons and finally the spongiosis. Then the clinical signs are expressed. The nervous signs characterised by behavioural alterations of the animals and kinetic abnormalities. The diagnosis of the disease is made by the observation of the histopathological lesions, the detection of Scrapie Associated Fibrils-SAF by EM, the immunohistochemical detection of prpsc i n histological samples or by electrophoresis (Western blotting test). BSE was proved to be transmissible to other animals and there is a possibility that it could be done to man through the food chain. According to the above in these years, from the appearance of the disease until now, have been taken bans from Great Britain as well as from E.U. for the eradication of the disease and the protection of the public health. These instructions should be followed by the authorities and additionally the consumers ought to be informed for the possible danger of various animal products.