Search PubMed⌕ Search

Biomedical subjects

J R Mead

Publications and source records attributed to J R Mead.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Cryptosporidium andersoni n. sp. (Apicomplexa: Cryptosporiidae) from cattle, Bos taurus.

A new species of Cryptosporidium is described from the feces of domestic cattle, Bos taurus. Oocysts are structurally similar to those of Cryptosporidium muris described from mice but are larger than those of Cryptosporidium parvum. Oocysts of the new species are ellipsoidal, lack sporocysts, and measure 7.4 x 5.5 microm (range, 6.0-8.1 by 5.0-6.5 microm). The length to width ratio is 1.35 (range, 1.07-1.50). The colorless oocyst wall is < 1 microm thick, lacks a micropyle, and possesses a longitudinal suture at one pole. A polar granule is absent, whereas an oocyst residuum is present. Oocysts were passed fully sporulated and are not infectious to outbred, inbred immunocompetent or immunodeficient mice, chickens or goats. Recent molecular analyses of the rDNA 18S and ITS1 regions and heat-shock protein 70 (HSP-70) genes demonstrate this species to be distinct from C. muris infecting rodents. Based on transmission studies and molecular data, we consider the large form of Cryptosporidium infecting the abomasum of cattle to be a new species and have proposed the name Cryptosporidium andersoni n. sp. for this parasite.

Animals↗
PubMedDate not supplied

Cryptosporidial infections in SCID mice reconstituted with human or murine lymphocytes.

Severe combined immunodeficient (SCID) mice were experimentally infected with Cryptosporidium parvum. Adoptive transfer of BALB/c thymocytes, spleen and bone marrow cells resulted in functional immunologic reconstitution followed by complete eradication of the cryptosporidial infection. Additional SCID mice were injected with human blood peripheral blood lymphocytes and were subsequently infected with C. parvum. The latter mice (SCID-hu-PBL) were at least partially reconstituted with human lymphoid tissues, as evidenced by flow cytometric identification of human cell populations in the SCID mouse spleens and the response of these cells to the T-cell mitogen phytohemagglutinin. The SCID-hu-PBL mice did not resolve the cryptosporidial infections, although a transient reduction in parasitemia was noted 4-6 wk post-reconstitution.

Animals↗