Biomedical subjects

Jinchuan Yang

Publications and source records attributed to Jinchuan Yang.

5 recordsLinked to original sources

PubMed2006

Differences between tethered polyelectrolyte chains on bare mica and hydrophobically modified mica.

This study investigates the structures of layers of amphiphilic diblock copolymers of poly(t-butyl styrene)-poly(styrene sulfonate) (PtBS-PSS) adsorbed on both the bare mica surface (hydrophilic) and an octadecyltriethoxysilane (OTE)-modified mica surface (hydrophobic). When the surface is rendered hydrophobic, the nonsoluble block exhibits stronger interaction with the surface and higher adsorbed masses are achieved. Interaction forces between two such adsorbed layers on both substrates were measured using the surface forces apparatus. The effect of salt concentration (Cs) and molecular weight (N) on the height of the self-assembled layers (L0) was examined in each case. The resulting scaling relationship is in good agreement with predictions of the brush model, L0 proportional to N(1.0) in the low-salt limit and L0N(-1) proportional to (Cs/sigma)(-0.32) in the salted regime, when adsorption takes place onto the hydrophobized mica surface. For adsorption on the bare mica surface, L0N(-0.7) proportional, variant Cs(-0.17) agrees with the scaling prediction of the sparse tethering model. The results suggest that, on the hydrophilic bare mica surface, the adsorbed amount is not high enough to form a brush structure and only very little intermolecular stretching of the tethered chains occurs; in contrast, the presence of the hydrophobic OTE layer increases the tethering density such that the polyelectrolyte chains adopt a brush conformation.

Journal Article↗

PubMed2005

stx2vha is the dominant genotype of Shiga toxin-producing Escherichia coli O157:H7 isolated from patients and domestic animals in three regions of China.

Shiga toxin-producing Escherichia coli(STEC) O157: H7 strains were isolated from domestic animals and patients from Xuzhou City, Jiangsu Province, China and the bordering Anhui and Henan Provinces and were examined for the stx genotype. Of 390 strains, 277 were identified as genotype stx2vha ; 41, stx2 ; 51, stx2-stx1 ; 1, stx2-stx2vha-stx1 ; 5, stx2-stx2vha ; and 15 were un-typeable. Of the 277 stx2vha-bearing isolates, 116 were isolated from goats; 42, cattle; 38, hens, and 35 from pigs. The study shows stx2vha is the dominant genotype and goats are an important reservoir.

Animals↗

PubMed2003

Isolation of Escherichia coli O157:H7 from dung beetles Catharsius molossus.

In an epidemiological survey, Escherichia coli O157:H7 was isolated from the intestine 4 of 113 dung beetle Catharsius molossus captured below ground at Tongshan County, Jiangsu Province of China. In parallel, 10 strains of E. coli O157:H7 were isolated from fecal samples of 383 diarrhea patients from the same region. Most importantly, using pulsed field gel electrophoresis (PFGE) of chromosomal DNA restriction fragments and PCR method, we found that the PFGE pattern and virulence genes of beetle isolates were identical to those of the human isolates, such as Shiga-toxins (stx) and enterohemorrhagic Escherichia coli hemolysin A (EHEC-hlyA). Therefore, dung beetle might acquire pathogenic E. coli O157:H7 through contact with feces of domestic animals.

Animals↗

PubMed2002

[Serological investigations on patients with hemolytic uremic syndromes due to enterohemorrhagic Escherichia coli O157:H7 infection].

OBJECTIVE: To investigate the etiological agent of patients with diarrhea followed by acute kidney failure symptoms in China, 1999. METHODS: Western blot was used to detect serum specific antibodies of patients against entero-haemorrhagic Escherichia coli hemolysin (EHEC-Hly) and lipo-polysaccharide of E. coli O157. RESULTS: Twenty-one and 16 of 42 patients showed positive reaction of specific IgG or IgM antibodies against EHEC-Hly respectively. Eleven of 42 serum samples were positive for having both IgG and IgM antibodies while 26 of 42 samples were positive for IgG or IgM. For E. coli O157 LPS test, 24 and 24 of 42 samples showed positive for IgG or IgM antibodies respectively. In 42 samples, 20 were positive for IgG and IgM while 29 were positive for IgG or IgM. CONCLUSIONS: Twenty-two of 42 samples were reacted with EHEC-Hly and E. coli O157 LPS, but 34 of 42 samples were positive for EHEC-Hly or E. coli O157. In combination of western blot results, bacterial isolation clinical symptoms and epidemiological investigation findings, it was reasonable to conclude that this cluster of patients with distinguish clinical symptoms was caused by E. coli O157:H7, which had never been reported in China. Hence serological methods with EHEC-Hly and E. coli O157 LPS are valuable for diagnosis of infections of E. coli O157:H7, when bacterial isolation is failed.

Adult↗

PubMed2002

[Study on diarrhea disease caused by enterohemorrhagic Escherichia coli O157:H7 in Xuzhou city, Jiangsu province in 2000].

OBJECTIVE: To investigate the proportion of hemorrhagic colitis (HC) caused by Escherichia coli O157:H7 in bacterial diarrhea in Xuzhou city, Jiangsu province. METHODS: All stool samples from patients with diarrhea were screened for O157 antigen, using Immuno-gold kits. Positive samples were cultured to detect the existence of pathogens. All of the HC patients confirmed by bacterial isolation and identification were investigated for clinical symptoms and laboratory tests. RESULTS: Of the diarrhea patients identified in Feng county in May, and in Tongshan county of Xuzhou city in June 2000, Jiangsu province 0.98% and 5.89% were caused by Escherichia coli O157:H7 respectively, confirmed by bacteriological isolation and identification of stool samples. At the early phase of hemorrhagic colitis, 18.5% patients had at least one abnormal clinical laboratory test results including protein in urea and increased BUN or creatinine that indicating the possibility of kidney damage. In 27 strains of E. coli O157:H7 isolated from those patients, 13 and 14 were identified as Shiga toxin producing and Shiga-toxin negative E. coli O157:H7 (Stx-positive or Stx-negative) respectively. By analysis of the two groups of patients divided by according to the nature of Shiga toxin, four of 13 patients of Stx-positive group showed positive urea protein. However only 1 of the 13 patients of Stx-negative group was urea protein positive. The decreased Platelets counts were observed in 6 of 13 patients with Stx-positive group, but only in 1 of 14 patients with stx-negative group. These differences were statistically significant. CONCLUSION: HC patients caused by E. coli O157:H7 were commonly seen (up to 5.89%) in Xuzhou city, Jiangsu province. Early laboratory tests should be conducted for HC patients as early as possible in order to find early indictor of kidney failure which was critical for prevention of hemolytic uremic syndrome.

Adolescent↗