Biomedical subjects

Chunmei Li

Publications and source records attributed to Chunmei Li.

34 records · Page 2Linked to original sources

PubMed2004

Gastric MALT lymphomas are divided into three groups based on responsiveness to Helicobacter Pylori eradication and detection of API2-MALT1 fusion.

Gastric MALT lymphoma shows unique features including regression by Helicobacter pylori eradication and API2-MALT1 fusion. We performed a molecular and clinicopathologic study for 115 cases. All eradication-responsive cases were devoid of API2-MALT1 fusion. All tumors positive for the fusion and all negative for H. pylori infection were nonresponsive to the eradication. Consequently, gastric MALT lymphomas were divided into three groups: Eradication-responsive and fusion-negative (group A, n = 72), eradication-nonresponsive and fusion-negative (group B, n = 22), and eradication-nonresponsive and fusion-positive (group C, n = 21). Group A tumors were characterized by low clinical stage and superficial gastric wall involvement, and group C tumors by low H. pylori infection rate, advanced clinical stage, and nuclear BCL10 expression. All group C tumors showed exclusively low-grade histology. Group B tumors, which have not been well recognized, frequently showed nodal involvement, deep gastric wall involvement, and advanced clinical stage, and sometimes an increased large cell component. A multivariate discriminant analysis revealed that responsiveness to the eradication could be predicted accurately by negative API2-MALT1 fusion, positive H. pylori infection, low clinical stage, and superficial gastric wall invasion, the former being the most important factor for the prediction. This 3-group categorization may be helpful for a comprehensive understanding of gastric MALT lymphoma.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Estrogenic and anti-androgenic activity of nitrophenols in diesel exhaust particles (DEP).

We recently isolated 4-nitrophenol, 2-methyl-4-nitrophenol, 3-methyl-4-nitrophenol, and 4-nitro-3-phenylphenol from diesel exhaust particles (DEP) and identified them as vasodilators. Because these compounds are alkylphenolic derivatives that might mimic hormones, we evaluated their estrogenic activity by human estrogen receptor (hER)-yeast screen assay. All of these nitrophenol derivatives except 2-methyl-4-nitrophenol exhibited estrogenic activity. Some estrogenic compounds are also anti-androgenic, so we measured the anti-androgenic activity of the same compounds by human androgen receptor (hAR)-yeast screen assay. We found anti-androgenicity in all four nitrophenols. Nitrophenols in DEP possess not only vasodilatory activity but also estrogenic and anti-androgenic activity.

Androgen Receptor Antagonists↗

PubMed2003

Poly(4-tert-butylstyrene) as a soluble polymer support in homogeneous catalysis.

[reaction: see text] Use of soluble poly(4-tert-butylstyrene) (PtBS) as a support in synthesis is demonstrated. These soluble polymers supported catalysts that were used in a monophasic medium. Subsequent separation of the catalysts after reaction was effected either by cooling- or by water-induced liquid/liquid-phase separation. Specific catalysts studied included both phosphine and DMAP nucleophilic catalysts. Low loadings of an azo dye quantified the efficiency of separation and recovery of these catalysts through multiple reaction cycles.

Journal Article↗

PubMed2003

Phase-selective solubility of poly(N-alkylacrylamide)s.

The extent of the phase-selective solubility of poly(N-alkylacrylamide)s was studied by UV-vis and fluorescence spectroscopy using poly(N-isopropylacrylamide) and poly(N-octadecylacrylamide) as representative polar and nonpolar poly(N-alkylacrylamide)s in a mixture of polar and nonpolar thermomorphic solvents. Phase-selective solubilities of greater than 10000:1 were seen with each labeled polymer in polar and nonpolar solvents such as heptane and DMF or heptane and 90% EtOH-H(2)O. Using a poly(N-acryloxysuccinimide) as a common precursor, a pool-split synthesis was devised to prepare a library of poly(N-alkylacrylamide)s whose members varied only in the size of their N-alkyl substituent. The solubilities of these library members were measured in both the polar and nonpolar phases of a thermomorphic heptane/90% EtOH-H(2)O mixture at 25 degrees C. Such solvent mixtures are miscible hot (70 degrees C) and biphasic cold (25 degrees C). The results show that poly(N-pentylacrylamide) is selectively soluble (>99.5%) in the polar EtOH-rich phase at rest. Poly(N-alkylacrylamide)s with larger N-alkyl groups are predominantly (C(6), 85%; C(7), 95%) or exclusively (>C(8), >99.5%) in the heptane-rich phase at rest.

Journal Article↗

PubMed2003

Using soluble polymers in latent biphasic systems.

A new strategy for carrying out reactions with a soluble polymer-bound reagent or catalyst is described. In this latent biphasic process, a solvent mixture at the cusp of immiscibility is prepared and used to carry out a reaction under homogeneous conditions. Then, after the reaction is complete, this mixture is perturbed by the addition of solvent or some other perturbing agent to produce a biphasic mixture. The product-containing phase is then separated under liquid/liquid conditions from the polymer-containing phase. The generality of this process is demonstrated using both dye-labeled polymers as surrogates for polymer-bound catalysts and with various polymer-bound organic and transition metal catalysts or reagents. In cases where a polymeric catalyst is used, the addition of fresh solvent and substrate reforms the original mixture allowing facile reuse of the catalyst.

Journal Article↗

PubMed2003

Measuring LCSTs by novel temperature gradient methods: evidence for intermolecular interactions in mixed polymer solutions.

Herein we describe studies of molecular interactions in thermoresponsive polymers as they go through phase transitions in aqueous solutions. By using our recently reported linear temperature gradient setup for studying the effects of temperature on chemical processes, we demonstrate the ability to probe lower critical solution temperature (LCST) behavior with excellent precision. This method also provides a simple and convenient way to assay the LCST of solutions containing more than one polymer and follow the clouding kinetics of polymer mixtures in real time.

Journal Article↗

PubMed2003

API2-MALT1 fusion defines a distinctive clinicopathologic subtype in pulmonary extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.

t(11;18)(q21;q21) is associated with mucosa-associated lymphoid tissue (MALT)-type lymphoma and results in API2-MALT1 fusion. However, its clinicopathologic significance remains unclarified. API2-MALT1 fusion is detected most frequently in MALT lymphomas primarily involving the lung. We therefore screened 51 cases of pulmonary MALT lymphoma for API2-MALT1 fusion, and studied its relationship with clinicopathologic factors including the immunohistochemical expression of BCL10, another MALT lymphoma-associated molecule. The API2-MALT1 fusion transcript was detected in 21 of 51 (41%) cases, and was correlated with the absence of any underlying autoimmune disease, and with a normal serum lactate dehydrogenase, a "typical" histology without marked plasmacytic differentiation or an increased number of large cells, and aberrant nuclear BCL10 expression. However, its prognostic impact was not identified in the limited follow-up (6 to 187 months, median 27). These data suggest that the API2-MALT1 fusion may be a causative gene abnormality unrelated to autoimmune disease. In addition, this alteration may define a homogeneous MALT lymphoma subtype that is clinically more indolent and histologically more "typical." Aberrant nuclear BCL10 expression may have a possible role as a tool to screen for this API2-MALT1 fusion. A large-scale study with a long follow-up is necessary to establish the prognostic significance of API2-MALT1 fusion.

Adult↗

PubMed2003

Age-related differences in the des IGF-I-mediated activation of Akt-1 and p70 S6K in mouse skeletal muscle.

The ability of des IGF-I to activate Akt-1 and p70 S6K in skeletal muscle with or without acute endurance exercise was examined in young and old mice. Mice were sacrificed 12 h after a moderate intensity treadmill run following an interperitoneal injection of des-IGF-I or saline. Blood and skeletal muscle were collected and IGF-I receptor, Akt-1 and p70 S6K protein contents and their phosphorylation status were determined. Injection of des IGF-I similarly decreased plasma glucose concentration in both young (P<0.01) and old mice (P<0.01) whereas plasma insulin and total IGF-I levels of young and old mice were not significantly changed by des IGF-I. Total IGF-I receptor protein and IGF-1 receptor phosphorylation were lower in aged mice (P<0.05). Basal phosphorylation of Akt-1 was lower in aged skeletal muscle (P<0.01) and this was not caused by changes in Akt-1 protein. In both young (P<0.01) and aged (P<0.05) mice, des IGF-I significantly increased the phosphorylation of Akt-1 at Ser 473. However, a des IGF-I-mediated increase in the p70 S6K phosphorylation (P<0.01) was only seen in young mice. Prior exercise decreased the total plasma IGF-I level in the presence of des IGF-I in aged mice. Des IGF-I-mediated Akt-1 and p70 S6K phosphorylation was not changed by exercise in either young or old mice. It is concluded that there was an aging-related resistance at the p70 S6K level in mouse skeletal muscle that could not be restored by prior exercise and this resistance is associated with lower IGF-I receptor number and Akt-1 phosphorylation in the aged skeletal muscle.

Aging↗

PubMed2003

Primary cutaneous marginal zone B-cell lymphoma: a molecular and clinicopathologic study of 24 asian cases.

Cutaneous marginal zone B-cell lymphoma is a recently proposed entity and constitutes a cutaneous counterpart of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). Borrelia burgdorferi infection has been suggested as a possible causative agent in European cutaneous cases of marginal zone B-cell lymphoma, whereas API2-MALT1 fusion and BCL10 mutation are highly associated with MALT lymphoma. Aberrant nuclear BCL10 expression may be closely correlated with API2-MALT1 fusion in gastric and pulmonary MALT lymphomas. We examined 24 Asian cases of cutaneous marginal zone B-cell lymphoma for B. burgdorferi involvement, API2-MALT1 fusion, BCL10 cellular expression, and BCL10 mutation. Neither Borrelia DNA nor API2-MALT1 fusion transcript was detected. Nuclear BCL10 expression was evident in tumor cells of 11 of 24 cases, although BCL10 mutation was found in one case only. Clinicopathologically, nuclear BCL10 was more frequently expressed in macroscopically nodular lesions than in plaques or papules (p = 0.0031). These data suggest that 1) B. burgdorferi infection may not play an important role in developing cutaneous marginal zone B-cell lymphoma in Asian cases, 2) neither API2-MALT1 fusion nor BCL10 mutation is closely associated with the pathogenesis, 3) aberrant nuclear BCL10 may frequently be expressed in the absence of these genetic abnormalities, and 4) nuclear BCL10 expression may be clinically important because it was observed in locally aggressive tumors.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Quantitative analysis of sinoatrial node using Doppler tissue images.

A method has been developed to quantitatively analyze sinoatrial nodes (SAN) using Doppler tissue images (DTI). Doppler tissue images of SAN are acquired using an intracardiac catheter via the superior vena cava in an in vivo experiment. A sequence of DTI images of a SAN is obtained, and a complete cycle of the SAN excitation is observed. The tissue acceleration of the SAN is extracted and quantitatively analyzed. The estimated time-acceleration curve of the SAN exhibits remarkable similarity to the electrocardiogram curve. This is the first report on such finding. The experimental results show that the tissue movement of the SAN correlates with electrical cardiac activities and closely associates with the different phases of the cardiac cycle. This method has great potential in characterizing the local cardiac activities through the study of the conduct pathway.

Acceleration↗

PubMed2003

Cardiac conductive system excitation maps using intracardiac tissue Doppler imaging.

OBJECTIVE: To precisely visualize cardiac anatomic structures and simultaneously depict electro-mechanical events for the purpose of precise underblood intervention. METHODS: Intracardiac high-resolution tissue Doppler imaging was used to map real time myocardial contractions in response to electrical activation within the anatomic structure of the cardiac conductive system using a canine open-chest model. RESULTS: The detailed inner anatomic structure of the cardiac conductive system at different sites (i.e., sino-atrial, atrial wall, atrial-ventricular node and ventricular wall) with the inside onset and propagation of myocardial velocity and acceleration induced by electrical activation was clearly visualized and quantitatively evaluated. CONCLUSION: The simultaneous single modality visualization of the anatomy, function and electrical events of the cardiac conductive system will foster target pacing and precision ablation.

Animals↗

PubMed2002

Effects of aging on hepatic IGF-I signaling.

Little is known regarding hepatic insulin-like growth factor-1 IGF-I signaling with aging despite the observation that other tissues demonstrate resistance to IGF-I with aging and declines in liver mass accompany aging. Our aim was to determine if the IGF-I-induced signaling process changes with aging. Young (5 months) and old (24 months) C57BL/6 mice hepatic tissues and blood samples were taken 20 min after an intraperitoneal injection of desIGF-I. Age had no significant effect on plasma glucose, insulin and total IGF-I levels. IRS-1 protein was significantly decreased (33%) with aging. Basal phosphorylation of IRS-1, PKB and ERK were unaffected whereas basal phosphorylation of CREB and FKHR were significantly increased (37 and 33%, respectively) with aging. desIGF-I caused a significant decrease in plasma glucose concentrations in both young (53%) and old (44%) mice. desIGF-I administration significantly increased the phosphorylation of IRS-1 in both young (104%) and old (89%) hepatic tissues. Similarly, the phosphorylation of PKB was dramatically enhanced in both young (527%) and old (350%) hepatic tissues after desIGF-I stimulation. By contrast, desIGF-I administration had no significant effects on the phosphorylation of ERK and phosphorylation of transcription factors CREB and FKHR in both young and old hepatic tissues. These data suggest that aging dose not impair IGF-I signaling in hepatic tissues.

Aging↗

PubMed2002

Soluble polymer-supported catalysts containing azo dyes.

[structure: see text] Azo benzene derivatives were incorporated into soluble polymer-bound catalysts by two different approaches. The first was to attach the dye to the polymer-bound catalysts, using the dye as an innocent spectator to study the phase preference, concentration, and recoverability of a catalyst. The second approach used an azo dye as a ligand to form an effective soluble polymer-bound Pd(II) catalyst for Heck reactions.

Journal Article↗

PubMed2002

[Analysis of prophylactic antibiotics for cesarean section].

OBJECTIVE: To study the appropriate antibiotic for prophylactic use in cesarean section. METHODS: The effects and side effects of prophylatic antibiotics in 1 266 cesarean section were studied retrospectively. Six regiems were engaged: (1) Penicillin and Ampicillin; (2) Mezlocillin sodium; (3) Sulbactam and Ampicillin; (4) Ciprofloxacin; (5) Clindamycin; (6) Cefacidal. RESULTS: The duration of postoperative body temperature return to normal of 1 - 6 group is (54.0 +/- 28.4) hours, (48.9 +/- 27.8) hours, (49.9 +/- 23.9) hours, (58.6 +/- 33.7) hours, (52.5 +/- 25.2) hours, (63.1 +/- 51.1) hours respectively. It was longer in cefazolin group than the others. There were less puerperal morbidity and side effects of Mezlocillin. CONCLUSIONS: Penicillin and Ampicillin are still the most common choices as prophylatic antibiotic in cesarean section. Mezlocillin is appropriate as well.

Ampicillin↗

PubMed2002

[Relationship between calpain-10 gene polymorphism, hypertension and plasma glucose].

OBJECTIVE: To detect the association among calpain-10(CAPN-10) gene polymorphism, hypentension and hyperglycemia. METHODS: 378 individuals in the present study were the second generation offsprings of 187 hypentensives and 19 1 nonhypertensives. Fasting plasma glucose (FPG), insulin, triglyceride and fibrinogen were determined. The polymorphism of UCSNP-43 and UCSNP-44 of CAPN 10 gene were analysed with PCR-SSCP method. RESULTS: (1)The frequency of G/G geno type of UCSNP-43 was higher in the second generation offsprings of the hypertensives than that in the nonhypertensive controls(86.6%, 75.4%, P < 0.05). (2) The frequenncy of G/G genotype of UCSNP-43 was higher in the hypertensive parents of the second generation offsprings in the hypertensive groups than that in the normotensive parent of the second generation offsprings of the nonhypertensive control groups (OR = 2.84, P = 0.01). After adjustment of age, sex and body mass index (BMI), the frequency of G/G genotype in the highest FPG-quartiles (FPG 5.42 +/- 0.1mmol/L) was much more than that in the lowest FPG quartiles (FPG 4.09 +/- 0.3 mmol/L) with OR of 3.32. CONCLUSIONS: Polymorphism of UCSNP-43 in CAPN-10 gene might be one of the genetic factors contributing to hypertension and diabetes mellitus in the population in Daqing city. It may be a predictor of type 2 diabetes mellitus (T2DM) in the decendents of hypertensives.

Adult↗

PubMedDate not supplied

Structure and properties of silk hydrogels.

Control of silk fibroin concentration in aqueous solutions via osmotic stress was studied to assess relationships to gel formation and structural, morphological, and functional (mechanical) changes associated with this process. Environmental factors potentially important in the in vivo processing of aqueous silk fibroin were also studied to determine their contributions to this process. Gelation of silk fibroin aqueous solutions was affected by temperature, Ca(2+), pH, and poly(ethylene oxide) (PEO). Gelation time decreased with increase in protein concentration, decrease in pH, increase in temperature, addition of Ca(2+), and addition of PEO. No change of gelation time was observed with the addition of K(+). Upon gelation, a random coil structure of the silk fibroin was transformed into a beta-sheet structure. Hydrogels with fibroin concentrations >4 wt % exhibited network and spongelike structures on the basis of scanning electron microscopy. Pore sizes of the freeze-dried hydrogels were smaller as the silk fibroin concentration or gelation temperature was increased. Freeze-dried hydrogels formed in the presence of Ca(2+) exhibited larger pores as the concentration of this ion was increased. Mechanical compressive strength and modulus of the hydrogels increased with increase in protein concentration and gelation temperature. The results of these studies provide insight into the sol-gel transitions that silk fibroin undergoes in glands during aqueous processing while also providing important insight in the in vitro processing of these proteins into useful new materials.

Hydrogel, Polyethylene Glycol Dimethacrylate↗