Monique Wyers

Pigeon circovirus infection: Pathological observations and suggested pathogenesis

Pigeon circovirus infection (PiCV) was diagnosed by light and transmission electron microscopy in 15 birds from five lofts in western France. Histopathological findings were suggestive of primary bursotropism of pigeon circovirus, followed by secondary systemic spread from the bursa of Fabricius, particularly to non-bursal lymphoid organs. The last stage of the disease was associated with various secondary (particularly bacterial) infections. In situ detection of apoptosis in the bursa of Fabricius indicated that PiCV was concomitant with an increase in bursal lymphocytic apoptotic events related to viral infection and leading to severe acquired immunosuppression.

Microvessel density in muscles of dogs with golden retriever muscular dystrophy

Due to the abundance of muscle, intravascular administration seems required for efficient gene or cell therapy of muscular dystrophy. Here, we examined the skeletal muscle microvasculature to assess if it is altered with dystrophin deficiency. Image analysis of capillaries was performed in three muscles of one- to ten-month-old golden retriever muscular dystrophy (GRMD) dogs and compared with healthy controls. In the gracilis muscle (and in the biceps brachii muscle) of 4- to 10-month-old GRMD dogs, the microvessel density (445+/-47 microvessels per mm(2)), the capillary to fiber ratio (111+/-26 capillaries per 100 myofibers), and the mean intercapillary distance (49+/-3 microm), were similar in affected and control dogs. The sartorius cranialis muscle in GRMD dogs showed microvessel depletion and increased intercapillary distance, but unaltered capillary to fiber ratio, relative to the controls. The mean diameter of microvessels and the total vascular area were higher in GRMD muscles than in control ones. In severely affected GRMD muscles at 7-10 months of age, fibrosis was associated with decreased microvessel density, increased intercapillary distance and microvessel diameter, but normal capillary to fiber ratio and total vascular area.

PRIMARY MENINGEAL T-CELL LYMPHOMA IN A HARBOR SEAL (PHOCA VITULINA)

Abstract A 15-year-old female harbor seal (Phoca vitulina) was referred to the Nantes Veterinary School, Nantes, France, with a clinical history of anorexia, seizures, and left hemiplegia. Cerebrospinal fluid analysis revealed large numbers of neoplastic lymphoid cells. After injection of a contrast agent into the cerebrospinal space, radiographs demonstrated an asymmetry of the right lateral ventricle. Necropsy examination revealed a marked edema of the right frontal lobe, extending to the basal nuclei and thalamus in the brain. Histological examination of the brain revealed leptomeningeal lymphoma. Immunohistochemical labeling demonstrated that the neoplasm was of T-cell origin. No significant macroscopic or microscopic lesions were observed in the other organs examined, including lymphoid organs. This is the first report of primary leptomeningeal lymphoma in a harbor seal.

Congenital cataract in 1-day-old French Mulard ducklings

Ocular opacity, associated with reluctance to move and inability to feed properly, was observed in approximately 1% of all newly hatched females from several related flocks of Mulard ducks. A 5-week follow-up study of 10 1-day-old affected females was performed, and they were compared with 10 control animals. Clinical, ocular and ultrasonographic examinations, and a complete necropsy of two animals per group with histological examination of the eye, were performed weekly. A bilateral immature cortical anterior cataract was diagnosed at ocular examination and confirmed by ultrasonography in affected ducks. Dyscoria was occasionally observed in affected animals. Severe cataract, with Morgagnian globules, severe anterior fibre liquefaction and disorganization were observed by photonic microscopy. No retinal or choroidal lesions were observed. No progression or repair of ultrasonographic and microscopic lesions could be detected during the 5 weeks of examination. The female predisposition for the ocular lesions suggests a congenital sex-linked recessive cataract.

Histology and Histomorphometry of the Tibial Diaphyseal Growth in Two Turkey Strains during the First Six Weeks after Hatching

The comparative cortical growth of the tibio‐tarsus was studied during the first six weeks after hatching in two turkey strains, a light and a heavy one. At one day post‐hatching the cortical appeared to be constituted in both strains of an embryonary non‐active fibrous bone tissue which had completely disappeared at one week. On and after one week the cortice was constituted of a fibrolamellar adult bone tissue elaborated on the periosteal part of the cortex. Its vascular pattern depended on the strain and on the thickness of the cortical faces. The histomorphometrical studies showed that the growth in thickness was earlier and faster in the heavy strain with a Total Diaphyseal Surface twice larger at 6 weeks but a Diaphyseal Cortical Ratio not significantly different since 3 weeks of age.

Avian monocytes, which are able to differentiate into macrophages and polykaryons in vitro, are precursors of authentic osteoclasts in vivo

Cell-mediated immunity (e.g. allograft rejection) is found ir: all vertebrates, and these reactions are known to depend on tltymirsderived cells in birds and mammals. However, the participation. of T-cells in the immunity of cartilaginous and bony fish has-not been demonstrated experimentally. One strategy for analysing Tcell function in fish would be to characterize the genes encoding polypeptid& homologues to the T-cell reeeptor @CR) molecules. We describe cDNA clones from the rainbow trout (Chcorhynchus mykiss) that have sequences very similar to amphibian, avian and mammalian TCR@ chains (PARTULA S., FELLAH S., D?!z CiUERRA A. a& CHARLEMAGNE J. (1994). C. R. Acad. Sci. Poris, 317, 765-770). Three complete trout &segments belonging to different families were analyzed, one of them had limited amino-acid sequence similarity to the human VP20 family. The ten trout p chain joining segments all retain the invariant mammalian Jp residues and comparison of 66 VP-Jp junctions led to the identification of a Dp-like sequence (GGACAGGG) which is shorter, but very similar to the chick&n Dg and mammalian Dpl sequences. There is considerable diversity ,dm the VP-DP and Dp-Jp junctions, suggesting the presence of Nnucleotides. The trout Cp extra-ceiiular domain is shorter !hai mammalian CDs and the hinge region has no~cysteine residue. The transmembrane Cp domain contains a lysine residue that ia mammals, is thought to be involved in charged interactions with members of the CD3 complex.