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Biomedical subjects

Bin Chen

Publications and source records attributed to Bin Chen.

At least 127 records · Page 7Linked to original sources
PubMed2005

[Study on the mechanism of protective effect of oral L-arginine on intestine after scald injury in rats].

OBJECTIVE: To explore the mechanism of protective effect of oral L-arginine (L-Arg) on the intestine after scald injury in rats. METHODS: Sixty-six Sprague-Dawley (SD) rats were randomly divided into three groups: i.e. normal control (N, n = 6, without treatment), oral L-arginine group (A, n = 30, with 1 ml 70 g/L of L-Arg per os 2 times a day from 2 post scald hour (PSH)) on with normal enteral feeding and group B (n = 30, with oral feeding of cold boiled water after scald). The changes in the content of superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), endothelin (ET), ET/NO ratio in the intestine and the level of plasma endotoxin (LPS) in portal vein were assessed at 6, 12, 24, 48, 72 PSH. Ileum tissue samples were harvested for pathological examination. RESULTS: The ET content in the intestinal tissue in A group at 6, 12 and 24 PSH (0.80 +/- 0.26 ng/g, 0.75 +/- 0.30 ng/g, 0.63 +/- 0.22 ng/g) was obviously lower than that in B group (1.26 +/- 0.38 ng/g, 1.34 +/- 0.37 ng/g, 0.97 +/- 0.19 ng/g, P < 0.05), but the NO contents in the intestine in A group at the same time points were significantly higher than that in B group (P < 0.01). The ET/NO ratio and the level of plasma endotoxin in A group were significantly lower than those in B group at each time point (P < 0.05 or 0.01). Pathological examination showed that the intestinal mucosal injury in the A group was obviously milder than that in the B group. CONCLUSION: Oral L-arginine was shown to have the effects to ameliorate ischemia reperfusion injury of the intestine and to protect the barrier function of the intestinal mucosa. This might be related to an increase in the NO level in intestinal mucosa resulting in maintenance of a stable ET/NO ratio.

Animals↗
PubMed2005

Elevated plasma tissue-type plasminogen activator (t-PA) and soluble thrombomodulin in patients suffering from severe acute respiratory syndrome (SARS) as a possible index for prognosis and treatment strategy.

OBJECTIVE: To detect the presence of endothelial injury in patients with severe acute respiratory syndrome (SARS) via enhanced levels of tissue-type plasminogen activator (t-PA) and soluble thrombomodulin (sTM). METHODS: Case patients were from Xuanwu Hospital (Capital University of Medical Sciences, Beijing, China), and all of them met clinical criteria for SARS. Healthy controls were some of the hospital employees. Endothelial injury bio-markers tPA and sTM were detected by commercial ELISA-methods. RESULTS: Classic plasma markers of endothelial injury, tPA and sTM significantly elevated in SARS patients in comparison to controls [t-PA: 1.48 +/- 0.16 nmol/L versus 0.25 +/- 0.03 nmol/L (P<0.0001), and sTM: 0.26 +/- 0.06 nmol/L versus 0.14 +/- 0.02 nmol/L (P<0.05)]. The only patient who died had extremely high levels of these endothelial injury markers (t-PA: 2.77 nmol/L and sTM: 1.01 nmol/L). The likelihood ratio analysis indicated the excellent discriminating power for SARS at the optimal cut-point of 0.49 nmol/L for tPA and 0.20 nmol/L for sTM, respectively. Significant numerical correlations were found among these endothelial injury markers in SARS patients. The numerical coefficient of correlation Pearson r between t-PA and sTM was 0.5867 (P<0.05). CONCLUSION: Increased plasma concentrations of tPA and sTM in patients with SARS suggest the possibility of endothelial injury. SARS patients might need anticoagulant therapy or fibrinolytic therapy in order to reverse intraalveolar coagulation, microthrombi formation, alveolar and interstitial fibrin deposition. It may not only provide a useful treatment and prognostic index but also allow a further understanding of the pathological condition of the disease.

Adult↗
PubMed2005

[Survey on reproductive health status of Shanghai college students].

OBJECTIVE: To explore reproductive health condition of college students in Shanghai and provide scientific basis for reproductive health education. METHODS: From July 2004 to March 2005, 1192 college students (majors including medicine, science and engineering, arts and culture; 618 medical students and 549 non-medical; 555 male and 612 female) from seven time-day colleges in Shanghai were investigated with a reproductive health questionnaire involving sex. The questionnaire was constituted by 72 topics, involving the need of education, sex attitude, sex videos, sex hygiene knowledge and sexually transmitted diseases (STDs), etc. RESULTS: 39.33% (459/1167) students thought they had accepted formal sex education; 49.19% (574/1167) students chose lecture as the favorite way; 41.90% (489/1167) students thought the reproductive health education would not increase the incidence of premarital sexual behavior; 64.10% (748/1167) students thought it was necessary to give college students reproductive health instructions and knowledge. On the other hand, we found 45.05% (250/555) boys and 27.45% (168/612) girls could accept the premarital sexual behaviors; 35.32% (196/555) boys and 39.38% (241/612) girls could accept premarital pregnancy; 44.39% (518/1167) students could calculate the safe period accurately; 71.38% (833/1167) students knew emergency contraception measures; 57.67% (673/1167) students knew how to and when to use condoms; To our surprise, only 2.19% (12/549) non-medical students and 12.14% (75/618) medical students knew exactly the whole 4 sexually transmitted diseases that needed to be essentially prevented in China. CONCLUSION: At present, the reproductive health condition of college students in Shanghai is sophisticated. Much more education on sex safety, self-protection skills and acquired immunodeficiency syndrome (AIDS) knowledge, etc should be reinforced.

Acquired Immunodeficiency Syndrome↗
PubMed2005

[A controlled randomized trial of the use of combined L-carnitine and acetyl-L-carnitine treatment in men with oligoasthenozoospermia].

OBJECTIVE: To determine the efficacy and safety of combined L-carnitine and acetyl-L-carnitine therapy in infertile males with oligoasthenozoospermia. METHODS: One hundred fifty patients with oligoasthenozoospermia were randomized selected into treatment and control groups. The treatment group with 90 patients were given L-carnitine (2 g/d) and acetyl-L-carnitine (1 g/d) orally, twice a day. The patients in control group were given Vitamin E 100 mg plus Vitamin C 100 mg, tid. The oral therapy lasted three months and patients accepted sperm analysis every one month. The L-carnitine level in seminal plasma was examined by high performance liquid chromatography (HPC). Side effects as well as pregnant rate were observed. RESULTS: In the treatment group, 85 patients out of 90 finished the three month treatment. Female spouses of 10 patients (11.6%) achieved pregnancy. Moreover, their forward motile sperm per ejaculation, total motile sperm, as well as the concentration of L-carnitine in seminal plasma were increased significantly (P < 0.01). In control group, 53 patients out of 60 completed three months therapy. Two pregnancy (3.7%) was observed. Though some increase was seen in number of forward motile sperm and total motile sperm per ejaculation, the changes were not statistically significant (P > 0.05). The difference of the pregnant rate between two groups was statistically significant. No side effects were found. CONCLUSION: Combined treatment with L-carnitine and acetyl-L-calmitine can be an effective and safe option for treating oligoasthenozoospermia by means of significantly improving forward motile sperm and total motile sperm per ejaculation, as well as increasing pregnant rates.

Acetylcarnitine↗
PubMed2005

[Therapeutic effect of TAX combined with Herceptin or epirubicin against breast cancer positive for Her-2/neu].

OBJECTIVE: To compare the therapeutic effects of biochemotherapy regimen with Herceptin plus taxol (TAX) and the chemotherapy regimen with epirubicin plus TAX against Her-2/neu-positive breast cancer and observe the changes in serum tumor markers in patients receiving biochemotherapy. METHODS: Seventy-three patients with advanced breast cancer positive for Her-2/neu as revealed by immunohistochemistry were divided into the study group (n=32) to receive treatment with the regimen of Herceptin plus TAX and control group (n=41) with the regimen of epirubicin(EPI) plus TAX. The therapeutic effects of the regimens were observed and in the study group, the relationship of the therapeutic effect with Her-2/neu positivity and changes in serum tumor markers were examined. RESULTS: The objective response rate and clinical benefit response rate were obviously higher in the study group than in the control group. In the study group, the clinical response rate of patients with positive immunostaining for Her-2/neu of grades 1+, 2+ and 3+ were 0%, 44.4% and 63.6%, respectively, as compared with those in the control group of 8.3%, 36.4%, and 38.9%, respectively, and the treatment resulted in lowered levels of serum tumor markers without significant changes in CA153, tps and CEA (P<0.05) after treatment, but CA125 showed no significant difference (P>0.05). CONCLUSIONS: In patients with advanced breast cancer with positive immunostaining for Her-2/neu of grade 3+, the regimen of Herceptin plus TAX can be more effective than the chemotherapeutic regimen of EPI plus TAX. Patients with Her-2/neu (+++) benefit more from the treatment than those with Her-2/neu (++). Serum CEA, CA153 and TPS levels also possess some value in evaluating the therapeutic effects of the regimens.

Adult↗
PubMed2004

Controlling the conformation of arylamides: computational studies of intramolecular hydrogen bonds between amides and ethers or thioethers.

The role of an ortho-alkylthioether group in controlling the conformation around the ring-N bonds of meta-connected arylamide oligomers is studied. Density functional theory (DFT) geometries of model compounds, including acetanilide, an ether acetanilide, and a thioether acetanilide, and their corresponding diamides, show that for either monoamide or diamide the alkyl side chain of the thioether should be perpendicular to the aryl plane, whereas for the ether monoamide, the alkyl side chain is in the aryl plane. DFT ring-N torsional potentials and constrained geometries of the model compounds demonstrate that carbonyl-S repulsion leads to a high torsional barrier and that intramolecular N-H...S and C-H...O hydrogen bonds and ring-amide conjugation lead to N-H having a preferred orientation in the benzene plane pointing towards S. The N-H bond lengthens and the ortho-ring C-H bond shortens in a regular pattern in the approach to the preferred orientation. Calculated IR frequencies for the N-H stretch show a clear red shift between model compounds without and with the thioether side chain.

Amides↗
PubMed2004

Intestinal perforation after combined liver-kidney transplantation for a case of congenital polycystic disease.

AIM: To highlight the intestinal perforation (IP), an uncommon and catastrophic complication after combined liver-kidney transplantation. METHODS: Combined liver-kidney transplantation (LKTx) with left kidney excision and a cyst fenestration procedure on the right kidney were performed on a case of 46-year-old female with congenital polycystic disease (CPCD). RESULTS: Two sites of IP were noted 40-50 cm proximal to ileocecal area during emergent laparotomy 10 d postoperatively. Despite aggressive surgical and medical management, disease progressed toward a fatal outcome due to sepsis and multiple organ failure 11 d later. CONCLUSION: Long duration of operation without venovenous bypass, overdose of steroid together with postoperative volume excess may all contribute to the risk of idiopathic multiple IPs. Microbiology and pathology inspections suggested that the infected cyst of the fenestrated kidney might be one reason for the fatal intra-peritoneal infection. Thus for the CPCD patients who seem to be very susceptible to infectious complications, any sign of suspected renal-infection found before or during LKTx is indication for the excision of original kidney. And the intensity of immunosuppression therapy should be controlled cautiously.

Fatal Outcome↗
PubMed2004

Principle component analysis in F/10 and G/11 xylanase.

A bioinformatics method was used to analyze F/10 and G/11 xylanase basing on principle component analysis, and a model was made to classify between these two folds with an ideal result. The principle components were predicated to be secondary structures, the components were analyzed with the architecture of each family, and found comparable with (beta/alpha)(8)-barrel of F/10 xylanase and right-hand structure of G/11 xylanase. Compared with sequence similarities, this method gave discriminating features a clear meaning. The largest component did not appear in the model, which revealed no difference between these two families.

Amino Acid Sequence↗
PubMed2004

A luminescent chemosensor with specific response for Mg2+.

A novel chemosensor, a cyclometalated platinum(II) bipyridyl acetylide complex containing a monoazacrown moiety in the acetylide ligand, which can signal Mg(2+) specifically and display large changes both in color and in luminescence intensity upon complexation with Mg(2+), is described.

Journal Article↗
PubMed2004

A new type of square columnar liquid crystalline phases formed by facial amphiphilic triblock molecules.

A series of three novel liquid crystalline amphiphilic molecules is reported which are composed of three incompatible molecular parts, a rigid terphenyl core, two lipophilic decyloxy chains in the terminal 4- and 4' '-positions, and a polar group in the lateral 2'-position. The polar group comprises a polyether chain, an amide group, and a polyhydroxyalkyl end group (1-acylamino-1-deoxy-d-sorbitol derivatives). The self-organization of these compounds was studied by polarized light microscopy, differential scanning calorimetry, and different X-ray diffraction techniques. These investigations confirm a novel liquid crystalline phase with a square 2D-lattice (square columnar mesophase, plane group p4mm). This structure is built up by a set of three distinct columns, namely columns containing the polar lateral groups, columns incorporating the alkyl chains, and ribbons of the rodlike terphenyl units. The calamitic cores form walls bounding square-shaped channels occupied by the microsegregated polar lateral chains. The lipophilic columns containing alkyl chains are at the corners interconnecting the aromatic rods end-to-end.

Journal Article↗
PubMed2004

Photosensitized oxidative deprotection of oximes to their corresponding carbonyl compounds by platinum(II) terpyridyl acetylide complex.

Platinum(II) terpyridyl acetylide complex (1) photosensitizes the oxidation of aldoximes 2-4, aliphatic acyclic and cyclic ketoximes 5-7, and aromatic ketoximes 8-10 into their corresponding carbonyl compounds with good to excellent yields in acetonitrile solution. This deprotection of oximes proceeds via singlet oxygen ((1)O(2)) mechanism. The photosensitizer can be easily separated from the product and unreacted starting material by extraction with ethyl acetate and reused for photooxidation without loss of (1)O(2)-generation capacity.

Journal Article↗
PubMed2004

A novel crosstalk mechanism between nuclear receptor-mediated and growth factor/Ras-mediated pathways through PNRC-Grb2 interaction.

It has been demonstrated that proline-rich nuclear receptor coregulatory protein (PNRC) is a nuclear receptor coactivator that interacts with nuclear receptors through an SH3-binding motif located in its C-terminus. In the present report, a physical interaction between PNRC and Grb2 (an adapter protein involved in growth factor/Ras-mediated pathways) has been demonstrated using the GST pull-down assay, the yeast two-hybrid assay, as well as by coimmunoprecipitation. Cotransfection and fluorescence imaging have also confirmed the colocalization of PNRC and Grb2 in mammalian cells. Transient transfection experiments have demonstrated that, by interacting with each other, Grb2 decreases the coactivator activity of PNRC for nuclear receptors, and that PNRC suppresses Grb2-mediated Ras/MAP-kinase activation. Furthermore, it was discovered that HeLa cells overexpressing PNRC grew more slowly when compared to matched controls. Additionally, using a RT-PCR analysis of mRNA on six pairs of cancer/noncancer tissues, PNRC expression was found to be significantly lower in breast cancer tissue than in noncancer tissue. Based on these findings, we believe that PNRC and Grb2, by interacting with each other, can suppress nuclear receptor-mediated regulation and growth factor-mediated regulation in human breast tissue. This is a newly identified crosstalk mechanism for modulating these two important types of regulatory pathways.

Adaptor Proteins, Signal Transducing↗
PubMed2004

A phosphorimidate rearrangement for the facile and selective preparation of allylic amines.

Allylic phosphorimidates, readily prepared from the combination of an allylic alcohol, an azide, and a chlorophosphite, undergo [3,3]-rearrangement under thermal conditions to provide single isomers of allylic phosphoramidates. This new rearrangement is tolerant of a range of substitution patterns on the reactants. Treatment of the products of the rearrangement with ethanethiolate followed by acid produces a protected allylic amine. This strategy thus provides an attractive and versatile procedure for the preparation of key synthetic intermediates, allylic amines.

Allyl Compounds↗
PubMed2004

Suggested protocol for collecting, handling and preparing peat cores and peat samples for physical, chemical, mineralogical and isotopic analyses.

For detailed reconstructions of atmospheric metal deposition using peat cores from bogs, a comprehensive protocol for working with peat cores is proposed. The first step is to locate and determine suitable sampling sites in accordance with the principal goal of the study, the period of time of interest and the precision required. Using the state of the art procedures and field equipment, peat cores are collected in such a way as to provide high quality records for paleoenvironmental study. Pertinent field observations gathered during the fieldwork are recorded in a field report. Cores are kept frozen at -18 degree C until they can be prepared in the laboratory. Frozen peat cores are precisely cut into 1 cm slices using a stainless steel band saw with stainless steel blades. The outside edges of each slice are removed using a titanium knife to avoid any possible contamination which might have occurred during the sampling and handling stage. Each slice is split, with one-half kept frozen for future studies (archived), and the other half further subdivided for physical, chemical, and mineralogical analyses. Physical parameters such as ash and water contents, the bulk density and the degree of decomposition of the peat are determined using established methods. A subsample is dried overnight at 105 degree C in a drying oven and milled in a centrifugal mill with titanium sieve. Prior to any expensive and time consuming chemical procedures and analyses, the resulting powdered samples, after manual homogenisation, are measured for more than twenty-two major and trace elements using non-destructive X-Ray fluorescence (XRF) methods. This approach provides lots of valuable geochemical data which documents the natural geochemical processes which occur in the peat profiles and their possible effect on the trace metal profiles. The development, evaluation and use of peat cores from bogs as archives of high-resolution records of atmospheric deposition of mineral dust and trace elements have led to the development of many analytical procedures which now permit the measurement of a wide range of elements in peat samples such as lead and lead isotope ratios, mercury, arsenic, antimony, silver, molybdenum, thorium, uranium, rare earth elements. Radiometric methods (the carbon bomb pulse of (14)C, (210)Pb and conventional (14)C dating) are combined to allow reliable age-depth models to be reconstructed for each peat profile.

Environmental Monitoring↗
PubMed2004

Applying public health strategies to primary immunodeficiency diseases: a potential approach to genetic disorders.

Primary immunodeficiency (PI) diseases are a group of primarily single-gene disorders of the immune system. Approximately 100 separate PI diseases have been described, but <20 probably account for >90% of cases. Although diverse, PI diseases share the common feature of susceptibility to infection and result in substantial morbidity and shortened life spans. Most important, prompt diagnosis and treatment can now lead to life-saving treatment and result in marked improvements in the quality and length of life for persons with PI diseases. In November 2001, a workshop was convened by CDC in Atlanta, Georgia, to discuss ways to improve health outcomes among persons with PI disease. A multidisciplinary panel of persons knowledgeable in PI diseases and public health met to identify and discuss public health strategies that can be applied to PI diseases and possibly for other genetic disorders. A systematic assessment based on the established public health framework was applied to the growing group of PI diseases, whose diverse genetic mutations span multiple components of the immune system but all lead to increased incidence and severity of infections. During the meeting, specialists in clinical immunology, public health, genetics, pediatrics, health communication, and ethics from state and federal agencies, academic centers, professional organizations, and advocacy foundations discussed the four components of the public health framework as they relate to PI diseases. These four components include 1) public health assessment (application of traditional public health methods to assess the occurrence and impact of PI diseases on communities); 2) population-based interventions (development, implementation, and evaluation of screening tests administered to newborns and clinical algorithms for early recognition of symptomatic persons to facilitate the earliest possible diagnosis and treatment for PI diseases); 3) evaluation of screening and diagnostic tools (to ensure their quality and appropriateness for identification of patients with PI diseases); and 4) communication (communication with and information dissemination to health-care providers and the public to facilitate prompt and appropriate diagnosis and intervention). The working group's deliberations focused on challenges and opportunities, priority research questions, and recommendations for future action for these four components. These recommendations, developed by workshop participants, will be useful to medical and public health professionals who are evaluating methods to increase recognition of PI diseases and other genetic disorders.

Adolescent↗
PubMed2004

Two pyranocoumarins from the seeds of Calophyllum polyanthum.

Two new pyranocoumarin diastereoisomers, calopolyanolides C (1) and D (2), were isolated from the ethanolic extract of the seeds of Calophyllum polyanthum, along with calopolyanolide A (3), calopolyanolide B (4), calanolide E2 (5), 5,7,3',4'-tetrahydroxyisoflavone (6), 3,4-dihydroxybenzoic acid (7), 3,4,5-trihydroxybenzoic acid (8), 2-hydroxy-4-methoxybenzoic acid (9), beta-sitosterol (10), beta-daucosterol (11), 3,5-dihydroxy-4-methoxybenzoic acid (12), 3,5-dimethoxybenzoic acid (13), and ursolic acid (14). Their structures were determined by MS, UV, and IR data and HMQC, HMBC, and NOESY experiments or by comparing them with authentic samples. X-ray crystallographic analysis confirmed the structure and relative configuration of 1.

Calophyllum↗