PubMed Health⌕ Search

Biomedical subjects

P G Engelkirk

Publications and source records attributed to P G Engelkirk.

9 recordsLinked to original sources
PubMed1989

Rapid detection of giardia antigen in stool with the use of enzyme immunoassays.

Enzyme-linked immunosorbent assays (ELISAs) using sera from rabbits and goats immunized with Giardia trophozoites were compared for detection of Giardia antigen in 300 stool specimens, 80 of which had positive results for Giardia by microscopic examination. The diagnostic accuracy of the two assays was similar, with sensitivities of 92% and 87% and specificities of 87% and 91% with the use of rabbit and goat antisera, respectively. Both ELISAs detected Giardia antigen in stool samples from asymptomatic as well as symptomatic excretors and from treated patients after organisms were no longer visualized by microscopic examination. The specificity of the assays was confirmed by consistently negative results on stool specimens from 10 neonates and 27 patients with enteric parasitic infections other than Giardia. Negative results also occurred when stool specimens containing 21 bacterial enteropathogens were tested. Potential confounding variables including multiple freezing and thawing episodes, prolonged storage, and stool filtration did not affect test results from clinical specimens. Antidiarrheal compounds did not interfere with assay results. Preservation of specimens in formalin did interfere with the assay, even if formalinized stool specimens were dialyzed before testing. For diagnosis of giardiasis, the ELISA is a sensitive and specific test that is not influenced by many environmental factors or by other enteropathogens. This test provides a practical and reliable method for evaluating large numbers of specimens in a variety of clinical and epidemiologic settings.

Animals↗
PubMed1988

Giardia lamblia.

Giardia is the most frequently identified enteric parasite in the United States, but much is not known about host-parasite interaction. Advances using immunodiagnostic techniques, endonuclease restriction analysis, surface-antigen detection methods, and measuring homologous and heterologous antibody responses are beginning to clarify the biology of Giardia.

Child↗
PubMed1984

An evaluation of single-dose metronidazole treatment for Gardnerella vaginalis vaginitis.

A randomized, nonblinded study was carried out to evaluate the efficacy of a single 2-g oral dose of metronidazole (Flagyl) versus a seven-day regimen in the treatment of "nonspecific" vaginitis. Using cultures for Gardnerella vaginalis, 14 (67%) of 21 women treated with the single 2-g dose and 19 (86%) of 21 women receiving the seven-day course were considered cured seven to ten days after treatment (P greater than .10). No difference in compliance was noted between the two groups, and the incidence of side effects likewise, was comparable.

Administration, Oral↗
PubMed1983

Taenia taeniaeformis (Cestoda) in the rat: ultrastructure of the host-parasite interface on days 8 to 22 postinfection.

The host-parasite interface was examined at the ultrastructural level 8 to 22 days postinfection (DPI) with metacestodes of Taenia taeniaeformis in the rat. Throughout this phase of development the parasite surface was invested with a dense surface coat of complex microtriches. At 8 to 14 DPI the plasma membrane of each microthrix extended beyond the distal end of the electron-dense tip, forming a slender tubular streamer over 10 microns long; by 18 DPI these had shortened and withered. Host cell processes interdigitated with the microtriches without evidence of harm to the parasite surface or the underlying tegument. The cells, on the other hand, became damaged, and their contents were shed into the matrix surrounding the microtriches. Lipid inclusions appeared within the parasites, and in the cytoplasm of surrounding inflammatory cells. By 22 DPI fibroblastic activity had resulted occasionally in the formation of a capsule surrounding a free-floating cysticercus, while in others intense granulocytic infiltration persisted with abutment and intermeshing of host cell and parasite surface processes; however there was still no evidence of any adverse effect on the microtriches, though many granulocytes were clearly pyknotic and degenerating. Evidently, the vigorous cellular response of the host is ineffective in either containing the expansion of the parasite or compromising the integrity of its surface membrane. The changing characteristics of the microtriches may be related to the need for dissolution of both intercellular matrices, and host cells as the vesicular organism rapidly increases in volume.

Animals↗
PubMed1982

Taenia taeniaeformis (Cestoda) in the rat: ultrastructure of the host-parasite interface on days 1 to 7 postinfection.

Ultrastructural observation were made on the host-parasite interface from 1 to 7 days postinfection (DPI) with Taenia taeniaeformis in the rat. Over this period the organism developed from a multicellular oncospheral mass, equivalent in size to a host hepatocyte, into a fluid-filled, grossly visible vesicle, the walls of which showed the arrangement of syncytial tegument, cytoplasmic bridges and subtegumental cell bodies typical of older cestodes. Microvilli, often branched, extended from the free, tegumental surface of the parasite from 1 DPI onwards. Fragments of the microvilli were pinched off distally, and became segmented and distended. Some were seen in intercellular spaces as far as 40 micrometers from the free tegumental surface; others were ingested by nearby host phagocytic cells, and appeared to swell and rupture within phagosomes. Microvillar branching was less frequent after 4 DPI and the microvilli became progressively shorter. By 7 DPI the tegumental surface had become irregular and the microvillar bases were broad and knoblike. Electron-dense deposits were present on the outer membrane of microvilli, the tips of which had become truncated or globular. Although phagocytic host cells were seen in migratory tracks and in contact with some organisms as early as 1 DPI, they caused no detectable damage to the parasites. However, many host cells, including hepatocytes and endothelial cells, were injured or destroyed; their contents contributed to the debris surrounding the parasite at all stages. Inclusions, probably lipid, appeared within the tegument and subtegumental cell bodies from 3 DPI onwards, and similar droplets were seen in adjacent host cells. The great increase in surface area of postoncospheral forms over the first week of infection, augmented by the display of multiple, microvillar projections, may provide not only or the absorption of nutrients required for growth, but also for the enhanced release of factors that affect survival of host cells and stimulate immunological defense mechanisms.

Animals↗