Biomedical subjects

Hong Tao

Publications and source records attributed to Hong Tao.

21 records · Page 2Linked to original sources

PubMed2002

CCR3 is required for tissue eosinophilia and larval cytotoxicity after infection with Trichinella spiralis.

The CCR3 binds at least seven different CC chemokines and is expressed on eosinophils, mast cells (MC), and a subset of Th cells (Th2) that generate cytokines implicated in mucosal immune responses. Using mice with a targeted disruption of CCR3 (CCR3(-/-)) and their +/+ littermates, we investigated the role of CCR3 in the amplification of tissue eosinophilia and MC hyperplasia in the mouse after infection with Trichinella spiralis. In CCR3(-/-) mice, eosinophils are not recruited to the jejunal mucosa after infection and are not present in the skeletal muscle adjacent to encysting larvae. In addition, the number of cysts in the skeletal muscle is increased and the frequency of encysted larvae exhibiting necrosis is reduced. The CCR3(-/-) mice exhibit the expected MC hyperplasia in the jejunum and caecum and reject the adult worms from the small intestine at a normal rate. This study is consistent with distinct functions for MC (adult worm expulsion) and eosinophils (toxicity to larvae) in immunity to a helminth, T. spiralis, and defines the essential requirement for CCR3 in eosinophil, but not MC recruitment to tissues.

Animals↗

PubMed2002

Helicobacter pylori impairs DNA mismatch repair in gastric epithelial cells.

BACKGROUND & AIMS: Helicobacter pylori infection is a major gastric cancer risk factor. H. pylori gastritis occurs more frequently in individuals with microsatellite instability-positive than those with microsatellite instability-negative gastric cancers, raising the possibility that H. pylori infection affects DNA mismatch repair (MMR). The aim of this study was to determine the effect of H. pylori on the expression of DNA MMR proteins and RNA in gastric epithelial cells. METHODS: Gastric cancer cell lines were cocultured with H. pylori, bacterial extracts, and Campylobacter jejuni or Escherichia coli. MutS (hMSH2 and hMSH6) and MutL (hMLH1, hPMS2, and hPMS1) DNA MMR protein and RNA levels were determined. RESULTS: All cell lines examined showed decreased levels of MutS and MutL DNA MMR proteins in a dose-dependent manner after coculture with H. pylori strains. The reduction in DNA MMR protein levels was caused by heat-sensitive H. pylori products. The levels of DNA MMR proteins were affected by C. jejuni but not by E. coli. RNA levels of hMSH2 and hMSH6 were also reduced after exposure to H. pylori. CONCLUSIONS: H. pylori infection of gastric epithelial cells leads to a decrease in DNA MMR proteins that is at least in part related to an H. pylori-induced decrease in messenger RNA levels of repair genes. These data suggest that H. pylori infection might lead to a deficiency of DNA MMR in gastric epithelial cells that may increase the risk of mutation accumulation in gastric mucosa cells and the risk of gastric cancer during chronic H. pylori infection.

Adaptor Proteins, Signal Transducing↗

PubMed2002

[Prevalence survey on Cyclospora cayetanensis and Cryptosporidium ssp. in diarrhea cases in Yunnan Province].

OBJECTIVE: To investigate the prevalence and distribution characteristics of Cyclospora cayetanensis and Cryptosporidium ssp. infection in diarrhea cases of Yunnan Province. METHODS: To collect fresh faeces from diarrhea cases in 7 counties/cities, examine the specimens by direct smear with iodine staining and modified acid-fast staining. RESULTS: The infection rate of C. cayetanensis and Cryptosporidium ssp. was 3.97% and 5.29%, respectively. The infection rate of the two pathogenic coccidians was as high as 10.64% and 8.51% in preschool children. C. cayetanensis was found in 3 counties and Cryptosporidium in 6 counties. CONCLUSION: Both C. cayetanensis and Cryptosporidium ssp. are prevalent in Yunnan Province with the latter distributed more widely, and the two pathogens are more prevalent in preschool children.

Adolescent↗