Surface ultrastructure of Parvatrema timondavidi developmental stages was studied using a scanning electron microscope. The metacercariae were collected from the marine clam, Tapes philippinarum, and juvenile and worms adult were recovered at 1, 2, 3, and 7 days after experimental infection of mice. The metacercariae had a large oral sucker and characteristic lateral projections. Around the lip of the oral sucker many type I and type II sensory papillae were observed, and type III papillae were located symmetrically on the medial side of the lateral projection. Numerous type I papillae were grouped around the genital pore. The tegumental spines were distributed over the worm surface except the lip of the sucker and genital pore. The 1-day old worm had a well-developed ventral sucker, with 6 type II sensory papillae on its outer surface and another 6 type I papillae on the inner side, Two small type I papillae were seen on the anterior side of the ventral sucker. The genital pore was and 15 type I papillae were grouped around it. The 2-, 3-, and 7-day worms revealed that as they grew to be adults, the spine tips became multipointed, the genital pore formed a genital atrium, and the cytoplasmic process became well differentiated. In 2- and 3-day worms 10 type II papillae encircling the lip of the oral sucker, and additional 4 papilled at the dorsal side of 4 dorsal type II papillae were a characteristic feature. The distribution pattern of sensory papillae around the oral sucker and genital pore, and 2 type I papillae on the anterior side of the ventra sucker, was so peculiar in P. timondavidi, that they seem to be useful keys for taxonomic differentiation from other gymnophallids.
parasitology-helminth-trematoda ; Parvatrema timondavidi ; surface ultrastructure ; scanning EM, sensory papilla ; spine ; cytoplasmic process

Congenital epulis of the newborn refers to a very rare gingival tumor that occurs along the anterior alveolar ridge in newborn infants. We report a neonate with 3*2*1.5cm mass protruding from the mouth. This was a pinky, red solid pedunculated mass, attached to the maxillar left canine region of the alveolus at birth. The tumor's large size partially obliterated the oral cavity and caused oral feeding difficulty but did not cause respiratory problems. We described the postnatal MR imaging findings, electromicroscopic, histochemical and immunohistochemical studies of this tumor in order to search for the histogenesis of the tumor. In our case, histochemically, individual tumor cells contained numerous PAS positive cytoplasmic granules. Immunohistochemically, strong and diffuse cytoplasmic staining for vimentin and NSE was observed. Staining with S-100 protein, cytokeratin, desmin, CEA, factor VIII-related antigen, lysozyme, EMA were negative. After total excision of the lesion in our case, we had no complication or recurrence either early or late(up to one year).
Alveolar Process ; Cytoplasm ; Cytoplasmic Granules ; Desmin ; Gingival Neoplasms* ; Humans ; Infant, Newborn* ; Keratins ; Magnetic Resonance Imaging ; Mouth ; Muramidase ; Parturition ; Recurrence ; S100 Proteins ; Vimentin ; von Willebrand Factor