Publications by authors named "Ubelaker J"

A description is presented of a new species of Subulura Molin, 1860, Subulura novomexicanus, collected from the spotted ground squirrel, Spermophilus spilosoma Bennett, 1833, in New Mexico. The males are 24 to 29 mm long, precloacal sucker 1.7-2.

View Article and Find Full Text PDF

Phyllodistomum funduli n. sp. is described from the urinary bladder and ureters of the plains topminnow, Fundulus sciadicus, from Cedar Creek in Keith County, Nebraska (41 degrees 11.

View Article and Find Full Text PDF

Examination of the cuticle of Trichinella pseudospiralis by transmission electron microscopy revealed an epicuticle, exocuticle, and mesocuticle, each divided into several layers. The epicuticle consisted of an outermost thin plasmalemmalike infracuticular material covering an inner trilaminar membrane. The exocuticle was granular and could be divided into 2 regions on the basis of density.

View Article and Find Full Text PDF

A model of contact lens-induced Acanthamoeba keratitis was developed in Yucatan micropigs. Pigs fitted with parasite-laden soft contact lenses developed corneal infections that clinically and histopathologically mimicked the human counterpart. Three distinct stages of disease became apparent and were categorized as: acute, condensed infiltrate, and resolution stages.

View Article and Find Full Text PDF

A crucial requirement for establishing corneal infection by the extracellular protozoal parasite, Acanthamoeba, is the ability of the parasite to bind to the corneal surface. In a series of in vitro studies, we examined the ability of Acanthamoeba castellanii [corrected] to adhere, invade, and damage normal, intact corneas of 11 mammalian and one avian species. A.

View Article and Find Full Text PDF

Human corneal buttons were exposed to trophozoites and cysts of Acanthamoeba castellanii for 12 hours. Examination of the buttons by scanning electron microscopy showed numerous trophozoites on the surface of the epithelium. Trophozoites examined by transmission electron microscopy had limited regions of attachment to the epithelium but extensive regions of attachment to each other.

View Article and Find Full Text PDF

Human corneal buttons were exposed to Acanthamoeba castellanii trophozoites and cysts for 12 hours at 35 degrees C. The buttons examined by light microscopy and scanning and transmission electron microscopy had severe epithelial ulceration and penetration by trophozoites. Observations on trophozoites below the surface suggest that penetration is accomplished by both secreted cytolytic enzymes and phagocytosis.

View Article and Find Full Text PDF

A widely utilized rabbit corneal cell line, SIRC, was characterized ultrastructurally and immunohistologically. Although SIRC cells are often described as being of epithelial origin, important ultrastructural and antigenic characteristics indicate that these cells are fibroblastic and not epithelial. SIRC cells lack desmosomes, cytoplasmic filaments, and cytokeratin-structures that are characteristic of corneal epithelial cells.

View Article and Find Full Text PDF

During the course of experiments examining the immunobiology of corneal transplants, the corneas of athymic, nude mice (nu/nu) were found to contain blood vessels that extended through the entire superficial stroma into the centermost portion of the cornea. The presence of corneal vessels was not related to the immunodeficient condition of the nude mouse since corneas from the severe combined immunodeficiency (SCID) mutant mouse strain were avascular and indistinguishable from corneas obtained from immunocompetent BALB/c mice. Furthermore, Langerhans cells were not found to accompany the blood vessels in the corneas of any of the nude mice examined.

View Article and Find Full Text PDF

Suppression of host inflammatory response in mice infected with Trichinella pseudospiralis was associated with host plasma corticosterone levels significantly higher than those seen in uninfected mice or in mice infected with T. spiralis. Increases in the population of mitochondria and depletion of lipid droplets in cells of the zona fasciculata were seen in the adrenals of mice infected with T.

View Article and Find Full Text PDF

1. Blood coagulation factor levels and the normal ranges of commonly used coagulation tests were established for Sigmodon hispidus. 2.

View Article and Find Full Text PDF

Based on morphological criteria of the male bursa, angiostrongylid nematodes often placed in the genus Angiostrongylus Kamensky (1905) were found to be heterogeneous, comprising species which are relegated to 5 distinct genera: Angiostrongylus Kamensky, 1905 (syn. Haemostrongylus Railliet and Henry, 1907); Parastrongylus Baylis, 1928 (syn. Pulmonema Chen, 1935, Rattostrongylus Schulz, 1951, Morerastrongylus Chabaud, 1972, Chabaudistrongylus Kontrimavichus and Delyamure, 1979); Angiocaulus Schulz, Orlov and Kutass, 1933; Gallegostrongylus Mas-Coma, 1977 (syn.

View Article and Find Full Text PDF

The biceps, semimembranosus, biceps femoris, and soleus muscles of female Rockland Wistar mice infected with either 1,000 Trichinella spiralis or 1,000 Trichinella pseudospiralis larvae were removed on days 12, 14, 16, and 18 post-infection (PI), sectioned and stained histochemically for their myosin ATPase activity. Light microscopic examination of the sections revealed that larvae of T. spiralis invade only the slow twitch muscle fibers, and those of T.

View Article and Find Full Text PDF

Adult Sigmodon hispidus, were given 50 third-stage larvae of Angiostrongylus costaricensis orally, intraperitoneally, subcutaneously, and on abraded and unabraded skin. Larvae could not penetrate unbroken skin but established normal infections in the cecal vasculature by all other routes. Significantly more adults were recovered after oral and intraperitoneal inoculation than subcutaneously or through abraded skin.

View Article and Find Full Text PDF

This is apparently the second report of a case of human meningoencephalitis caused by the nematode Micronema deletrix. The patient had severe granulomatous meningoencephalitis with numerous foci of hemorrhage and encephalomalacia. Numerous adult female and larval M.

View Article and Find Full Text PDF

Unicellular glands are reported from the scolex and anterior neck region of Hymenolepis diminuta and H. nana. Despite positive staining reactions with the presumptive neurosecretory stains, paraldehyde-fuchsin and chrome-alum-hematoxylin, ultrastructurally these glands exhibit many non-neural characteristics.

View Article and Find Full Text PDF

New fish species and geographic records for Rhabdospora thelohani Laguessé, 1895 (rodlet cells) are presented. Additionally, the ultrastructure of R. thelohani in Alburnoides bipunctatus ohridanus Karaman, Borostomias antarcticus (Lönnberg), Leuciscus cephalus albus Bonaparte and Rutilus rubilio (Bonaparte) is compared with that reported by other authors and with members of Subphylum Apicomplexa.

View Article and Find Full Text PDF

The processes of spermatogenesis and spermiogenesis in Hymenolepis diminuta were studied by electron microscopy using improved preparative techniques. Spermatogonia (Type A) are characterized by nuclei 3.79 (+/- 0.

View Article and Find Full Text PDF