DEVELOPMENTAL STAGES OF GRASSENEMA PROCAVIAE PETTER, 1959 (COSMOCERCOIDEA: ATRACTIDAE) FOUND IN THE STOMACH OF CAPE HYRAX (PROCAVIA CAPENSIS).

Morphological examination was made of the larval forms of Grassenema procaviae (Cosmocercoidea: Atractidae), an autoinfective and viviparous nematode parasite in the stomach of Cape hyrax (Procavia capensis). Three different larval stages (second-, third- and fourth-stages), and the adult stage were found among the worms collected at necropsy of 3 hosts, which were reared in a zoo in Japan. Molting phases between the larval stages and the final molt to the adult stage were also observed. It was considered that the gravid female delivers the second-stage larva, which develops to the adult stage through 3 molts. The cephalic structure was identical throughout the second to adult stages; all with transparent filaments extending from the mouth. Because starch grains were frequently found attached to the filaments and the worm intestinal lumen also contained starch grains ingested, the filaments were surmised to act as nutrient catchers.

Morphological observation and first molecular characterization of Grassenema procaviae Petter, 1959 (Cosmocercoidea: Atractidae) in the stomach of Cape hyrax (Procavia capensis) raised in a zoo in Japan.

The superfamily Cosmocercoidea comprises three families: Cosmocericidae, Kathlaniidae and Atractidae. Information on the nucleotide sequences of the Cosmocercoidea is quite limited, and the molecular classification of the whole superfamily has been slow to progress. The genus Grassenema of the family Atractidae is a parasitic nematode group that occurs in the digestive tract of hyraxes and includes three species: Grassenema procaviae, G. dendrohyraci, and G. hyracis. The type species of the genus, G. procaviae, was isolated from the digestive tract of Cape hyraxes (Procavia capensis) and has the potential to cause gastric ulcers. Although G. procaviae is a common parasite of Cape hyraxes, no genetic information for the parasite is currently available. In this study, we obtained the first genomic sequences of G. procaviae and performed detailed morphological observations. Furthermore, molecular phylogenetic analysis was performed, and the taxonomic position of the parasite was evaluated using 18S and 28S rDNA sequences. Those data will be useful for molecular identification of G. procaviae and future phylogenetic analysis within the Atractidae.

[A patient with mediastinal liposarcoma showing dedifferentiation].

A 70-year-old man visited our hospital with fever and general malaise. Chest CT scanning showed a large tumor shadow in the anterior mediastinum. The tumor was resected. It consisted of a portion rich in fat on the anterior mediastinal side and a solid portion on the left thoracic cavity side. Pathological examination demonstrated liposarcoma (myxoid type). The solid portion was considered to have resulted from dedifferentiation of the cystic portion. Mediastinal liposarcoma accounts for less than 1% of all mediastinal tumors. To our knowledge, there have been no previous reports of patients with myxoid-type mediastinal liposarcoma showing dedifferentiation.