Biomedical subjects

Feng Feng

Publications and source records attributed to Feng Feng.

25 records · Page 2Linked to original sources

PubMed2003

[Imaging diagnosis of mucinous cystic neoplasms of the pancreas].

OBJECTIVE: To assess the imaging findings in mucinous cystic neoplasms (MCNs) of the pancreas. METHODS: The imaging manifestations of 18 cases with pathologically proven MCNs were analyzed retrospectively. RESULTS: The cystic features of MCNs could be demonstrated by ultrasonography (US), computed tomography (CT), or magnetic resonance imaging (MRI). Compared with US, CT and MRI are appropriate for localizing diagnosis (100%). One half of the cases have classic imaging findings of the MCNs, where as the diagnosis of remaining cases could be supported by clinical findings. CONCLUSIONS: Imaging technique plays an important role in the diagnosis of MCNs.

Adult↗

PubMed2003

[Role of uncoupling proteins in the pathogenesis of obesity and type II diabetes].

Uncoupling proteins (UCPs) are mitochondria carrier proteins,which are able to dissipate the proton gradient of the inner mitochondria membrane. The uncoupling procedure reduces the amount of ATP generated through an oxidation of fuels. Therefore, UCPs are suggested as candidate genes for human obesity or type II diabetes mellitus. Experimental evidences,that genetically engineered mice over expressing different UCP homologues were resistant to diet-induced obesity and 45 bp insertion polymorphism in the UCP2 3' untranslated region and C-55T in UCP3 promoter region were associated with obesity related phenotype, supported the hypothesis. The roles of UCP genes in polygenic obesity and type II diabetes are evaluated and discussed in this paper.

English Abstract↗

PubMed2002

YfcX enables medium-chain-length poly(3-hydroxyalkanoate) formation from fatty acids in recombinant Escherichia coli fadB strains.

Expression of Escherichia coli open reading frame yfcX is shown to be required for medium-chain-length polyhydroxyalkanoate (PHA(MCL)) formation from fatty acids in an E. coli fadB mutant. The open reading frame encodes a protein, YfcX, with significant similarity to the large subunit of multifunctional beta-oxidation enzymes. E. coli fadB strains modified to contain an inactivated copy of yfcX and to express a medium-chain-length synthase are unable to form PHA(MCL)s when grown in the presence of fatty acids. Plasmid-based expression of yfcX in the FadB(-) YfcX(-) PhaC(+) strain restores polymer formation. YfcX is shown to be a multifunctional enzyme that minimally encodes hydratase and dehydrogenase activities. The gene encoding YfcX is located downstream from yfcY, a gene encoding thiolase activity. Results of insertional inactivation studies and enzyme activity analyses suggest a role for yfcX in PHA monomer unit formation in recombinant E. coli fadB mutant strains. Further studies are required to determine the natural role of YfcX in the metabolism of E. coli.

Escherichia coli↗

PubMed2002

Evidence for human immunodeficiency virus type 1 replication in vivo in CD14(+) monocytes and its potential role as a source of virus in patients on highly active antiretroviral therapy.

In vitro studies show that human immunodeficiency virus type 1 (HIV-1) does not replicate in freshly isolated monocytes unless monocytes differentiate to monocyte-derived macrophages. Similarly, HIV-1 may replicate in macrophages in vivo, whereas it is unclear whether blood monocytes are permissive to productive infection with HIV-1. We investigated HIV-1 replication in CD14(+) monocytes and resting and activated CD4(+) T cells by measuring the levels of cell-associated viral DNA and mRNA and the genetic evolution of HIV-1 in seven acutely infected patients whose plasma viremia had been <100 copies/ml for 803 to 1,544 days during highly active antiretroviral therapy (HAART). HIV-1 DNA was detected in CD14(+) monocytes as well as in activated and resting CD4(+) T cells throughout the course of study. While significant variation in the decay slopes of HIV-1 DNA was seen among individual patients, viral decay in CD14(+) monocytes was on average slower than that in activated and resting CD4(+) T cells. Measurements of HIV-1 sequence evolution and the concentrations of unspliced and multiply spliced mRNA provided evidence of ongoing HIV-1 replication, more pronounced in CD14(+) monocytes than in resting CD4(+) T cells. Phylogenetic analyses of HIV-1 sequences indicated that after prolonged HAART, viral populations related or identical to those found only in CD14(+) monocytes were seen in plasma from three of the seven patients. In the other four patients, HIV-1 sequences in plasma and the three cell populations were identical. CD14(+) monocytes appear to be one of the potential in vivo sources of HIV-1 in patients receiving HAART.

Amino Acid Sequence↗

PubMed2002

A sensitive optode membrane for berberine using conjugated polymer as sensing material.

A new optode membrane for the sensitive determination of berberine based on fluorescence quenching of a conjugated polymer, poly(2,5-dimethoxy-phenyldiacetylene) (PDPA), is proposed. Incorporated in a membrane composed of plasticized poly(vinyl chloride) (PVC), the conjugated polymer exhibits better stability than those small sensing molecules regarding its excellent optical properties and lipophilic characteristics. Moreover, upon the introduction of a negatively charged lipophilic additive (tetraphenylborate salt) into a PVC membrane, the optode displayed enhanced sensitivity. In addition, satisfactory analytical sensing characteristics for determining beberine were obtained in terms of the selectivity, reversibility and reproducibility with a detecting range of between 7.5 x 10(-7) mol l(-1) and 7.5 x 10(-4) mol l(-1). The optode membrane has been applied to determine berberine in commercial tablets. The results showed a good agreement with those obtained by the pharmacopoeial method.

Berberine↗

PubMed2002

[Comparison of radiographs and magnetic resonance imaging in the detection of carpal lesions in patients with rheumatoid arthritis].

OBJECTIVE: To compare MR imaging with radiographs in detection of the erosions of the wrists in patients with rheumatoid arthritis (RA). METHODS: In 50 wrists of 25 patients with RA, radiographs of AP projection and MR imaging examination were performed within 1 week. The MRI sequences were SE T1-weighted image, FSE T2-weighted image, and GE T2* weighted image in coronal plane. Gd-DTPA enhanced SE T1-weighted image with same parameters of pre-contrast administration SE T1WI was performed in 25 wrists, which showed prominent lesions in each 25 patients. RESULTS: In 50 wrists of 25 patients with RA, bone erosions were found by MR images compared to radiographs in 46 versus 14 wrists, respectively. There were 170 sites of carpal erosions found by MR images, while radiographs found only 23 sites of carpal erosions. Among them triquetrum and lunate were the most frequently involved sites. Significant difference (P < 0.001) was statistically found between conventional radiography and MR imaging in detection of erosions of the wrists of RA. MR imaging also permitted demonstrating synovitis and joint effusion in the wrists. Gd-DTPA-enhanced images allowed distinguishing pannus changes from joint effusion. CONCLUSION: MRI is superior to conventional radiography with respect to detection of bone erosion in wrists. For those whose conventional radiographs show suspected RA, MRI examination should be advised for the early diagnosis.

Adult↗

PubMed2002

[Fat at sacroiliac joints: MR imaging findings (comparison and analysis of 18 volunteers and 52 patients with ankylosing spondylitis)].

OBJECTIVE: In aid of MR imaging diagnosis of ankylosing spondylitis (AS), MRI findings of sacroiliac (SI) joints in volunteers were compared with those in patients with AS, with special reference to the fat findings. METHODS: 18 normal volunteers and 52 AS patients underwent the MRI examinations with the same protocols, i.e., SE T1WI, FSE T2WI, GE T2*WI sequences were taken using a 0.3T imager. All the images were observed and analyzed by two radiologists. RESULTS: Symmetric or patchy distribution fat component either in sacrum and/or ilium was detected in 52.8% of SI joints of volunteers. Thin zone distribution of fat was seen in 35.6% of SI joints of AS patients, which was adjacent to the erosion and sclerosis. In another 25.0% of SI joints of AS patients, the distribution of fat component was found similar to that of the normal volunteers. Cartilage changes were detected in 85.6% of the SI joints of AS patients. In addition, bone erosion, sclerosis and subchondral bone marrow edema were also detected. CONCLUSION: Subchondral fat infiltration associated with erosion and sclerosis should be considered as sacroiliitis. The knowledge of the characteristics of fat component could be helpful for evaluating sacroiliac joints.

Adipose Tissue↗