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Biomedical subjects

Li Tan

Publications and source records attributed to Li Tan.

45 records · Page 3Linked to original sources
PubMed2003

Identification of interaction between PAI-2 and IRF-3.

HeLa cells transfected with plasminogen activator inhibitor-2 ( PAI-2 ) were protected from TNF- alpha-induced apoptosis. The apoptosis protection by PAI-2 is dependent on a 33 amino acids fragment between helix C and D of PAI-2, which may be due to the interaction of PAI-2 with some intracellular proteins. In this study, the yeast two-hybrid system was used to screen a HeLa cells cDNA library constructed during apoptosis with the fragment between helix C and D of PAI-2 as bait. We retrieved a clone that encodes 98 amino acids of C-terminus of interferon regulatory factor-3 (IRF-3). Co-immunoprecipitation experiments confirmed the interaction between PAI-2 and IRF-3 in vivo. IRF-3 belongs to a family of the IRF transcription factors and has been shown to participate in a large number of biological processes. These data suggest that IRF-3 may be involved in the apoptosis protection and antiviral function of PAI-2.

Apoptosis↗
PubMed2002

Tomato LeAGP-1 arabinogalactan-protein purified from transgenic tobacco corroborates the Hyp contiguity hypothesis.

Functional analysis of the hyperglycosylated arabinogalactan-proteins (AGPs) attempts to relate biological roles to the molecular properties that result largely from O-Hyp glycosylation putatively coded by the primary sequence. The Hyp contiguity hypothesis predicts contiguous Hyp residues as attachment sites for arabino-oligosaccharides (arabinosides) and clustered, non-contiguous Hyp residues as arabinogalactan polysaccharide sites. Although earlier tests of naturally occurring hydroxyproline-rich glycoproteins (HRGPs) and HRGPs designed by synthetic genes were consistent with a sequence-driven code, the predictive value of the hypothesis starting from the DNA sequences of known AGPs remained untested due to difficulties in purifying a single AGP for analysis. However, expression in tobacco (Nicotiana tabacum) of the major tomato (Lycopersicon esculentum) AGP, LeAGP-1, as an enhanced green fluorescent protein fusion glycoprotein (EGFP)-LeAGP-1, increased its hydrophobicity sufficiently for chromatographic purification from other closely related endogenous AGPs. We also designed and purified two variants of LeAGP-1 for future functional analysis: one lacking the putative glycosylphosphatidylinositol (GPI)-anchor signal sequence; the other lacking a 12-residue internal lysine-rich region. Fluorescence microscopy of plasmolysed cells confirmed the location of LeAGP-1 at the plasma membrane outer surface and in Hechtian threads. Hyp glycoside profiles of the fusion glycoproteins gave ratios of Hyp-polysaccharides to Hyp-arabinosides plus non-glycosylated Hyp consistent with those predicted from DNA sequences by the Hyp contiguity hypothesis. These results demonstrate a route to the purification of AGPs and the use of the Hyp contiguity hypothesis for predicting the Hyp O-glycosylation profile of an HRGP from its DNA sequence.

Amino Acid Sequence↗
PubMed2002

Endotoxin activity of Moraxella osloensis against the grey garden slug, Deroceras reticulatum.

Moraxella osloensis is a gram-negative bacterium associated with Phasmarhabditis hermaphrodita, a slug-parasitic nematode that has prospects for biological control of mollusk pests, especially the grey garden slug, Deroceras reticulatum. This bacterium-feeding nematode acts as a vector that transports M. osloensis into the shell cavity of the slug, and the bacterium is the killing agent in the nematode-bacterium complex. We discovered that M. osloensis produces an endotoxin(s), which is tolerant to heat and protease treatments and kills the slug after injection into the shell cavity. Washed or broken cells treated with penicillin and streptomycin from 3-day M. osloensis cultures were more pathogenic than similar cells from 2-day M. osloensis cultures. However, heat and protease treatments and 2 days of storage at 22 degrees C increased the endotoxin activity of the young broken cells but not the endotoxin activity of the young washed cells treated with the antibiotics. This suggests that there may be a proteinaceous substance(s) that is structurally associated with the endotoxin(s) and masks its toxicity in the young bacterial cells. Moreover, 2 days of storage of the young washed bacterial cells at 22 degrees C enhanced their endotoxin activity if they were not treated with the antibiotics. Furthermore, purified lipopolysaccharide (LPS) from the 3-day M. osloensis cultures was toxic to slugs, with an estimated 50% lethal dose of 48 microg per slug, thus demonstrating that the LPS of M. osloensis is an endotoxin that is active against D. reticulatum. This appears to be the first report of a biological toxin that is active against mollusks.

Animals↗
PubMed2002

Astronaut-centered philosophy for designing manned space system.

Astronaut-centered design philosophy is a new concept suggested by the authors for manned space system design. It stems from human-centered design philosophy. Human-centered design means that human role is regarded as important basis and foundation for system design. At the beginning, the engineers used to adopt technology-centered philosophy for designing complex system, but much practice proved that the technology-centered design philosophy won't work, resulting in lower system safety and performance. So it has been currently replaced by human-centered philosophy. As examples, the principles of human-centered automation of the International Civil Aviation Organization and NASA JSC's Human-rating Requirements were introduced. At last, the astronaut-centered design philosophy and its requirements were put forward by the authors. These requirements consist of: general requirements, man-machine interaction requirements, man-environment interaction requirements and interpersonal relationship requirements.

Astronauts↗
PubMed2002

[Evaluation of myometrial invasion in endometrial carcinoma].

OBJECTIVE: To determine the value of preoperative ultrasound, intraoperative gross visual inspection and postoperative bulk specimen measurement in evaluating the diagnosis of myometrial invasion in endometrial carcinoma. METHODS: A total of 133 cases of women with endometrial carcinoma were analyzed focusing on evaluating the diagnosis of myometrial invasion by preoperative ultrasound, intraoperative gross visual inspection and postoperative bulk specimen measurement. The relationship between CA(125) and endometrial carcinoma of 91 cases of endometrial carcinoma was also analyzed. RESULTS: In the diagnosis of myometrial invasion and deep myometrial invasion, ultrasound showed a sensitivity of 62.6% and 47.8% and a specificity of 67.7% and 90.0%, respectively, and intraoperative gross visual inspection showed a sensitivity of 59.6% and 73.9% and a specificity of 76.5% and 94.6%, respectively. The sensitivity of postoperative bulk specimen measurement was 70.0% and 94.4% and the specificity was 92.0% and 97.7%, respectively. The levels of CA(125) had no correlation with depth of myometrial invasion in endometrial carcinoma, but they had correlation with International Federation of Gynecology and Obstetrics (FIGO) stage. CONCLUSIONS: Preoperative ultrasound, intraoperative gross visual inspection and postoperative bulk specimen measurement were helpful to the diagnosis of depth of myometrial invasion in endometrial carcinoma, and postoperative bulk specimen measurement seems to be better. CA(125) could not evaluate depth of myometrial invasion in endometrial carcinoma.

Endometrial Neoplasms↗
PubMed2002

Sonographic patterns and differential diagnosis of cystic renal carcinomas.

OBJECTIVE: To study the sonographic features and patterns of cystic renal carcinomas. METHODS: Thirteen cases of cystic renal carcinoma confirmed by operation and pathology were examined by ultrasonography, and the cystic walls, septa and solid mural nodules were studied. RESULTS: Solid mural nodules of some cases and irregular thickening of the cystic walls and septa were characteristic findings for the ultrasonic diagnosis of cystic renal carcinomas. According to their pathologic mechanisms and sonographic features, cystic renal carcinomas were classified into 3 patterns: unilocular cystic mass, multiloculated cystic mass and cystic-solid mass. CONCLUSIONS: Typical cystic renal carcinomas can be well diagnosed, while atypical cases may be misdiagnosed as benign renal cysts by ultrasonography. Color Doppler ultrasonography and needle aspiration guided by ultrasonography are helpful in the diagnosis of these atypical cases.

Adult↗
PubMedDate not supplied

Oral glutamine ameliorates chemotherapy-induced changes of intestinal permeability and does not interfere with the antitumor effect of chemotherapy in patients with breast cancer: a prospective randomized trial.

AIMS AND BACKGROUND: Sixty patients with breast cancer were randomly assigned to oral glutamine or placebo pre-neoadjuvant chemotherapy (CEF regimen). METHODS AND STUDY DESIGN: Oral glutamine supplementation was continued for at least 12 days. Patients kept a daily record of diarrhea and stomatitis. The plasma glutamine level, intestinal permeability (lactulose-mannitol test), and tumor size were analyzed. The expression of Ki-67 and PCNA antigens in breast carcinoma was assessed. RESULTS: The plasma glutamine level was significantly higher in the glutamine group than in the placebo group (420.39 +/- 52.39 mmol/L vs 309.76 +/- 42.34 mmol/L, P < 0.05). After one cycle of chemotherapy, the lactulose-mannitol ratio was higher in the placebo group than in the glutamine group (0.0630 +/- 0.0091 vs 0.0471 +/- 0.0094, P < 0.05). No differences were observed in the grades of stomatitis and diarrhea, in the changes in tumor size, and in the expression of Ki-67 and PCNA antigens between the two groups. CONCLUSIONS: Prophylactic oral glutamine could ameliorate the neoadjuvant chemotherapy-induced increase in intestinal permeability, but had no significant positive clinical effect on stomatitis and diarrhea and did not interfere with the antitumor effect of chemotherapy.

Administration, Oral↗