Biomedical subjects

R Guo

Publications and source records attributed to R Guo.

At least 73 records · Page 4Linked to original sources

PubMed2001

[The sensitized reaction of non-ionic microemulsion on the determination of trace Ni(II) by fluorescence quenching method with salicyfluorone].

A new selective and sensitive spectrofluorimetric method in non-ionic microemulsion for the determination of trace Ni(II) in water has been developed. This method is based on the quenching of fluorescence of Triton X-100/n-C5H11OH/n-C9H20/H2O microemulsion system due to the formation of complex Ni(II)-SAF-Triton X-100. The results show that there is a linear relationship in the rang of 0.5-2.5 ng.25 mL-1 for Ni(II). The sensitivity in microemulsion is higher than that in micelle. Satisfactory results are obtained for Ni(II) in water sample.

Chelating Agents↗

PubMed2001

[The structures and characteristic infrared spectra of beta-DDB and its derivatives].

The characteristic infrared bands of the 3, 4-methylenedioxy-5-methoxybenzoate, 6-Br-3, 4-methylenedioxy-5-methoxybenzoate, beta-DDB (6, 6'-dimethoxy-4, 5, 4', 5'-dimethylenedioxy-2, 2'-dimethoxycarbonylbiphenyl) and its five derivatives were assigned. The effects of the substituents of these compounds on their IR data were discussed. The results indicated the varying of ester alkyl mainly influences the C=O double band stretching mode, but has little effects on the C=C double band stretching mode of the phenyl. When the H atom was substituted by other substituents, the absorptions of the C=O and C=C both changed.

Biphenyl Compounds↗

PubMed2000

Time-dependent inhibition of immune complex-induced lung injury by catalase: relationship to alterations in macrophage and neutrophil matrix metalloproteinase elaboration.

Rats were subjected to acute lung injury by the intra-alveolar formation of IgG immune complexes of bovine serum albumin (BSA) and anti-BSA. In this model of injury, complement activation occurs and large numbers of neutrophils invade the interstitium and alveolar space. In the present study, animals were treated with intratracheal catalase concomitantly with anti-BSA or after a lag period of 5-120 min. Catalase treatment at time-zero or at 5 min post injury failed to prevent lung injury as indicated by permeability change, histological features, and neutrophil influx. However, treatment after a delay of 15-30 min (but not 120 min) afforded substantial protection. Consistent with past findings [19], lung injury was accompanied by an accumulation of matrix metalloproteinase 9 (MMP-9) in bronchoalveolar lavage (BAL) fluid. There was a strong correlation between inhibition of injury and reduction in MMP-9 levels. In vitro studies conducted in parallel revealed that unstimulated alveolar macrophages did not produce measurable MMP-9, while there was a large induction following exposure to the same immune complexes that initiated injury in vivo. MMP-2 was also slightly upregulated under the same conditions. Concomitant treatment with catalase greatly inhibited MMP-9 production by macrophages in response to immune complexes, but this treatment had little effect on basal production of either MMP-9 or MMP-2 by macrophage. The same concentration of catalase that suppressed MMP-9 elaboration also inhibited the production of tumor necrosis factor alpha. In contrast, when neutrophils were treated with catalase and then exposed to immune complexes, the antioxidant failed to prevent the release of either MMP-2 or MMP-9. Taken together, these findings demonstrate that antioxidant treatment interferes with elaboration of MMPs by alveolar macrophages. Protection against lung injury is correlated with reduction in MMP levels in the BAL fluid.

Animals↗

PubMed2000

Origin of the high piezoelectric response in PbZr1-xTixO3

High resolution x-ray powder diffraction measurements on poled PbZr1-xTixO3 (PZT) ceramic samples close to the rhombohedral-tetragonal phase boundary (the so-called morphotropic phase boundary) have shown that for both rhombohedral and tetragonal compositions the piezoelectric elongation of the unit cell does not occur along the polar directions but along those directions associated with the monoclinic distortion. This work provides the first direct evidence for the origin of the very high piezoelectricity in PZT.

Journal Article↗

PubMed2000

Examination of novel non-phosphorus-containing phosphotyrosyl mimetics against protein-tyrosine phosphatase-1B and demonstration of differential affinities toward Grb2 SH2 domains.

Inhibitory potencies were compared of several mono- and dicarboxy-based pTyr mimetics in Grb2 SH2 domain versus PTP1B assays. Although in both systems pTyr residues provide critical binding elements, significant differences in the manner of recognition exist between the two. This is reflected in the current study, where marked variation in relative potencies was observed between the two systems. Of particular note was the poor potency of all monocarboxy-based pTyr mimetics against PTP1B when incorporated into a hexapeptide platform. The recently reported high PTP1B inhibitory potency of similar phenylphosphate mimicking moieties displayed in small molecule, non-peptide structures, raises questions on the limitations of using peptides as platforms for pTyr mimetics in the discovery of small molecule inhibitors.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Inhibition of Grb2 SH2 domain binding by non-phosphate-containing ligands. 2. 4-(2-Malonyl)phenylalanine as a potent phosphotyrosyl mimetic.

Nonhydrolyzable phosphotyrosyl (pTyr) mimetics serve as important components of many competitive Grb2 SH2 domain inhibitors. To date, the most potent of these inhibitors have relied on phosphonate-based structures to replace the 4-phosphoryl group of the parent pTyr residue. Reported herein is the design and evaluation of a new pTyr mimetic, p-malonylphenylalanine (Pmf), which does not contain phosphorus yet, in Grb2 SH2 domain binding systems, approaches the potency of phosphonate-based pTyr mimetics. When incorporated into high affinity Grb2 SH2 domain-directed platforms, Pmf is 15-20 times more potent than the closely related previously reported pTyr mimetic, O-malonyltyrosine (OMT). Pmf-containing inhibitors show inhibition constants as low as 8 nM in extracellular Grb2 binding assays and in whole cell systems, effective blockade of both endogenous Grb2 binding to cognate erbB-2, and downstream MAP kinase activation. Evidence is provided that use of an N(alpha)()-oxalyl auxiliary enhances effectiveness of Pmf and other inhibitors in both extracellular and intracellular contexts. As one of the most potent Grb2 SH2 domain-directed pTyr mimetics yet disclosed, Pmf may potentially have utility in the design of new chemotherapeutics for the treatment of various proliferative diseases, including breast cancer.

Adaptor Proteins, Signal Transducing↗

PubMed2000

[Monitoring on blood lead and cadmium in Nanjing inhabitants from 1983 to 1998].

Blood lead (Pb) and cadmium (Cd) of residents in Nanjing were monitored from 1983 to 1998. The results showed that the blood Pb concentration was male > female, smokers > nonsmokers. Blood Pb in female nonsmokers increased gradually during recent ten years. Blood lead level was also significantly different between urban residents and suburban residents in 1998. Blood Cd concentration in female nonsmoker < male nonsmokers < male smokers < female smokers, male smokers > male nonsmokers. The blood Cd of female nonsmokers kept steady in the last ten years. The concentration of blood Cd of urban residents was accordant with suburban residents in 1998.

Adult↗

PubMed2000

The formation of the chick ileal muscle layers as revealed by alpha-smooth muscle actin immunohistochemistry.

The genesis of intestinal smooth muscle layers was immunohistochemically investigated by use of an antibody to alpha-smooth muscle actin (alpha-SMA) in the developing chick ileum. Myoblast cells positive for alpha-SMA were already found in the presumptive circular muscle layer on E 8.5. On E 11.5 radially oriented muscle fibers were protruded from the outermost layer of the developing circular musculature and then formed a tuft-like aggregates. These radial muscle bundles were bent into an L-shape. The long distal extension of muscle bundles run parallel to the long axis of the ileal loop and developed into the longitudinal muscle layer. The obliquely oriented muscle fibers, locating at the intermuscular space of the muscularis propria, probably are to be considered a remnant of the short extension of radial muscle bundles. The muscularis mucosae was formed by the processes equivalent to the genesis of longitudinal muscle layer. On E 14.5 centripetally oriented muscle fibers emerged from the innermost layer of circular musculature. The long distal extension of centripetal fibers lay along the inner surface of developing circular musculature. On E 19.5 the longitudinal muscle layer of the muscularis mucosae was newly formed by separating from the circular musculature. The villous myoblast cells initially developed from the innermost layer of the muscularis mucosae on E 18.5, and were widely distributed in the lamina propria mucosae on E 20.5. Temporal and chronological pattern in expression of alpha-SMA was observed during the development of the chick intestinal smooth muscle. By E 14.5 the entire layer of the muscularis propria was intensely immunostained for alpha-SMA, but from E 15.5 onward the staining intensity gradually began to decrease from the outer half of the circular musculature. Finally, the immunoreactivity was localized in the inner layer of circular muscle and the longitudinal muscle layer. A possible functional role of this inner layer of circular muscle is discussed.

Actins↗

PubMed2000

Clinical-scale production of granulocyte progenitor and post-progenitor cells using daniplestim, leridistim, Progenipoietin, Promegapoietin and autologous plasma.

BACKGROUND: Supplementation of PBPC autografts with ex vivo expanded PBMC may significantly reduce or eliminate the period of neutropenia associated with high-dose chemotherapy. METHODS: Unmanipulated growth-factor mobilized PBMC were expanded in media containing daniplestim, leridistim, Promegapoietin, and Progenipoietin (DLPP) and 2% autologous plasma at 4 x 10(5) PBMC/mL, first in 25 cm(2) T-flasks, with sampling on Days 7, 10, 13 and 15, and then in 1264 cm(2) Nunclon Cell Factories, with sampling on Days 7 and 13. RESULTS: In T25-flasks, maximal CFU-GM expansion ([38.2 +/- 9.5]-fold) occurred on Day 10, whereas maximal total cell expansion ([6.7 +/- 1.1]-fold) occurred on Day 15. Production of CD15(+)CD11b(-) and CD15(+)CD11b(+) granulocytic post-progenitors (3.0 +/- 0.4 x 10(6) and 3.7 +/- 0.9 x 10(6), respectively) was also maximal at Day 15. Compared with the previously studied combination of Flt3L, PIXY321, G-CSF, GM-CSF and Epo, the DLPP cocktail performed similarly, with the exception of yielding larger GM colonies at Day 10 and fewer granulocyte post-progenitors on Day 15. In Cell Factories, CFU-GM were expanded (31.6 +/- 14.5)-fold, while total nonadherent cells were expanded (2.6 +/- 0.5)-fold. The two stack Cell Factory cultures seeded with 1.0 x 10(8) unselected PBMC produced approximately 3.3 x 10(6) CFU-GM and 1.3 x 10(8) myeloid post-progenitors. DISCUSSION: Whereas expansion of cell numbers, CFU-GM and granulocytic post-progenitors in Cell Factories mirrored that achieved in T25-flasks, future preclinical studies with the DLPP cytokine combination may be performed in small volumes, with subsequent translation to the larger volume Cell Factories. Sufficient expansion can be achieved using the DLPP cytokine combination in the Cell Factories to provide the numbers of progenitors required for clinical trials.

Cell Culture Techniques↗

PubMed2000

An abundant DNA binding protein from the hyperthermophilic archaeon Sulfolobus shibatae affects DNA supercoiling in a temperature-dependent fashion.

The DNA binding protein Ssh10b, a member of the Sac10b family, has been purified from the hyperthermophilic archaeon Sulfolobus shibatae. Ssh10b constitutes about 4% of the cellular protein. Electrophoretic mobility shift assays showed that Ssh10b first bound a double-stranded DNA fragment with an estimated binding size of approximately approximately 12 bp, forming distinct shifts, until the DNA was coated with the protein. Binding of more Ssh10b resulted in the formation of smears of lower mobilities. The migration pattern of the smearing Ssh10b-DNA complexes was affected by temperature, whereas that of complexes associated with the distinct shifts was not. Interestingly, Ssh10b was capable of constraining negative DNA supercoils in a temperature-dependent fashion. While the ability of the protein to constrain supercoils was weak at 25 degrees C, it was enhanced substantially at 45 degrees C or higher temperatures (up to 80 degrees C). Taken together, our data suggest that archaeal proteins of the Sac10b family may affect the topology of chromosomal DNA in thermophilic archaea at their growth temperatures.

Amino Acid Sequence↗

PubMed2000

Chemical characteristics and relative bioavailability of supplemental organic zinc sources for poultry and ruminants.

Eight commercially available organic Zn products and reagent-grade ZnSO4 x 7H2O (Zn Sulf) were evaluated by polarographic analysis, and solubility in .1 M K2HPO4-KH2PO4 buffer (pH 5), .2 M HCl-KCl buffer (pH 2), and deionized water. Fractions from these solubility tests were evaluated by gel filtration chromatography for structural integrity. Degree of chelation was generally positively related to chelation effectiveness determined by polarography. The organic sources were Zn methionine complex A (Zn MetA), Zn methionine complex B (Zn MetB), Zn polysaccharide complex (Zn Poly), Zn lysine complex (Zn Lys), Zn amino acid chelate (Zn AA), Zn proteinate A (Zn ProA), Zn proteinate B (Zn ProB), and Zn proteinate C (Zn ProC). Three experiments were conducted to estimate the relative bioavailability of Zn from the organic Zn supplements for chicks and lambs when added at high dietary levels to practical diets. Bone Zn concentration increased (P < .001) as dietary Zn increased in both experiments. When Zn Sulf was assigned a value of 100% as the standard, multiple linear regression slope ratios of bone Zn from chicks fed 3 wk regressed on dietary Zn intake gave estimated relative bioavailability values of 83 +/- 14.6 and 139 +/- 16.9 for Zn AA and Zn ProA, respectively, in Exp. 1 and 94 +/- 11.6, 99 +/- 8.8, and 108 +/- 11.4 for Zn Poly, Zn ProB, and Zn ProC, respectively, in Exp. 2. In Exp. 3, 42 lambs were fed diets containing Zn Sulf, Zn ProA, Zn AA, or Zn MetB for 21 d. Based on multiple linear regression slope ratios of liver, kidney, and pancreas Zn and liver metallothionein concentrations on added dietary Zn, bioavailability estimates relative to 100% for Zn Sulf were 130, 110, and 113 for Zn ProA, Zn AA, and Zn MetB, respectively. Except for Zn ProA, which was greater, the organic Zn supplements had bioavailability values similar to that of Zn Sulf for chicks and lambs. Bioavailability of organic Zn products was inversely related to solubility of Zn in pH 5 buffer in chicks (r2 = .91) and pH 2 buffer in lambs (r2 = .91), but not to an estimate of degree of chelation.

Animal Feed↗

PubMed2000

Relationship between metabolic phenotype of N-acetylation and bladder cancer.

OBJECTIVE: To study the relationship between metabolic phenotype of acetylation and bladder cancer. METHODS: Totally 203 healthy volunteers and 67 patients with bladder cancer were investigated with caffeine as a metabolic probe. Urine samples were collected in 2-6 hours after a cup of 140 mg coffee was taken, and the caffeine metabolites, 5-acetylamino-6-formylamino-1-methyluracil (AFMU) and 1-methylxanthine (1X) were analyzed by high performance liquid chromatography (HPLC). The frequency histogram and probit plot were constructed to select the critical value which was used to assess slow and fast acetylation status both in healthy volunteers and patients with bladder cancer. RESULTS: The peak height ratios of AFMU and 1X (AFMU/1X) were from 0.06 to 6.50 for healthy volunteers and 0.10 to 6.31 for patients with bladder cancer, both with the critical value of 1.10. Of 203 healthy volunteers involved in this study, 26.3% were slow acetylacors, as compared to 46.3% with slow acetylacors in patients with bladder cancer. The odds ratio is 2.376, and the gene frequency for healthy volunteers and patients with urinary bladder cancer were 0.5218 and 0.6804, respectively. CONCLUSIONS: N-acetylation status in the Chinese population is polymorphic and completely concordant with that determined with other metabolic probes. Slow acetylators are significantly associated with bladder cancer.

Acetylation↗

PubMed2000

[Generation of cytotoxic T lymphocytes induced with HSP-PC70 derived from tumor cells].

OBJECTIVE: To investigate the killing effect of cytotoxic T lymphocytes (CTLs) induced with heat shock protein-peptide complexes (HSP-PC70) derived from tumor cells. METHODS: Cell culture, flow cytometric analysis, affinity chromatography for protein extraction and purification, SDS-PAGE, Western blotting, CTL induction and expansion, and LDH release were used. RESULTS: 63.5% of the HcaF cells expressed HSP-PC70 on their membrane by FCM analysis under physiological condition, and the expression was 75.5% of the stressed cells (P < 0.01). HcaF cells had high HSP70 expression and inducibility. The cytotoxic activity of the CTLs induced with HSP70 obtained by affinity chromatography from HcaF cells was 84.2%, 47.9% and 14.8% respectively at E/T ratio of 50 : 1, 25 : 1 and 12.5 : 1. The CTLs were CD8 positive T cells. All mice which received CTL injection got long period survival (over 90 days, P < 0.01), compared with control group (10.6 days). CONCLUSION: HSP-PC70 derived from tumor cells has strong immunogeneicity, and can activate CTLs with high peculiarity and killing activity. HSP-PC70 induced CTL adoptive immunotherapy can be a promising treatment for human to fight cancers.

Animals↗

PubMed2000

[Anterior segment reconstruction and secondary posterior chamber intraocular lens implantation supported by fibromembrane].

OBJECTIVE: To evaluate the methods and effects of anterior segment reconstruction and secondary posterior chamber intraocular lens (IOL) implantation supported by fibromembrane in pupillary area. METHODS: Anterior segment was reconstructed in 86 eyes with different anterior segment disorders. Anterior segment reconstruction includes: partial penetrating keratoplasty, loosing front adhesion, suturing detached peripheral iris, loosing rear adhesion, reshaping pupil, perforating fibromembrane in the pupillary area. The IOL was secondarily implanted into the posterior chamber, and the patients were followed up in 3 - 32 months. RESULTS: The surgery was successful in all patients. The postoperative visual acuities in 71 eyes were >or= 0.5 (82.6%), including >or= 0.9 (39.5%) in 34 eyes and <or= 0.2 in 15 eyes (17.4%). After IOL implantation, the IOL correctly centered was in 68 eyes (79.1%), and deviated in 18 eyes (20.9%). Anterior chamber hemorrhage occurred in 5 eyes, 4 of them were recovered by conservative treatment and the blood membrane in another eye was sucked out through its primary incision. All patients had slight postoperative inflammation and without severe long term complications. CONCLUSION: With the support of enough fibromembrane in pupillary area, anterior segment reconstruction and secondary posterior chamber IOL implantation can be performed, thus IOL suture fixation is not necessary, and its associated complications can be avoided.

Adolescent↗

PubMed2000

[Sarcomatoid carcinoma in breast].

OBJECTIVE: To observe the distinctive pathomorphological features of sarcomatoid carcinoma (SC) in mammary gland as well as its diagnosis and differential diagnosis. METHODS: 1 538 malignant tumors of the breast were reviewed. 15 cases (0.98%) were diagnosed as SC. AE1/AE3, carcinoembryonic antigen (EMA), vimentin, S-100 protein, actin, estrogen receptor (ER) and progesterone (PR) were performed with SP immunohistochemical staining methods. RESULTS: The SC were divided into four morphological types according to the distinctive features of their sarcomatoid components. (1) Polymorphic sarcoma type: sarcomatoid components are polymorphic; (2) Spindle cell type: sarcomatoid components consisted of spindle cells; (3) Osteoclastic giant cell type: a huge number of osteoclastic giant cells in the sarcomatoid components; (4) Myxocartilage type: myxocartilaginoid components are seen in the tumor tissue. With immunohistochemical staining, the expression rates of AE1/AE3, EMA, vimentin, S-100 protein and actins in the epithelial components were in 11, 15, 11, 12 and 8 cases respectively, and sarcomatoid components were in 10, 13, 13, 13 and 10 cases respectively, while ER and PR were positive only in 2 cases. CONCLUSION: Sarcomatoid carcinoma of the breast should be distinguished from carcinosarcoma, desmoplastic carcinoma, sarcoma, nodular fasciitis and fibromatosis.

Actins↗

PubMed2000

[Studies on separation and identification of Rhizoma coptidis brugs based on microemulsion thin-layer chromatography].

OBJECTIVE: To investigate the use of microemulsion TLC for the separation and identification of Rhizoma Coptidis drugs. METHOD: Thirteen Rhizoma Coptidis drugs were separated and identified with six kinds of SDS/n-C4H9OH/n-C7H16/H2O microemulsions as mobile phase on polyamide film. Effects of microemulsions on separation were investigated. RESULTS: The best mobile phase was the O/W microemulsion(containing 75% water). Compared with general mobile phases, the separation and detection could be improved and the test conditions were more tolerant. CONCLUSION: This new method is simple, accurate and efficient for the separation and identification of Rhizoma Coptidis drugs.

Berberine↗

PubMed2000

[The clinical application of stereography in laryngology with "the three-dimensional reconstruction system of medical faultage photograph"].

OBJECTIVE: To study the value of the clinical application of stereography in laryngology. METHODS: Taken by Microtek E6 scanner, the CT faultage images were inputted in personal computer and reconstructed to a three-dimensional stereograph by "the three-dimensional reconstruction system of medical faultage photograph". The software was compiled using IDL5.2, a complete, integrated software environment for data analysis, visualization and application. RESULTS: The three-dimensional laryngeal graph could be incised in random, displayed in optional degree, and was rotatable, semitransparent and measurable. The tumor could identified be identified by a special color and revealed through translucent parenchyma and cartilage. Reconstruction stereographs of laryngeal and hypopharyngeal cancer of 26 patients were investigated. CONCLUSION: It is convenient for popularization because the three-reconstruction process is built on a personal computer without the need of any equipment for image acceleration. It is very helpful for ENT surgeon to define the range of the tumor, to fix on surgical pattern accurately and to anticipate the operational course.

Adult↗

PubMed2000

[Supracricoid partial laryngectomy in laryngeal cancer].

OBJECTIVE: To assess the effectiveness of supracricoid partial laryngectomy in the treatment of laryngeal cancer and the reconstructed laryngeal functions. METHODS: This study involved 29 patients operated on from 1978 to 1998 using this surgical procedure. In these cases, 18 were male and 11 were female with a mean age of 55.4 years (range, 38 to 70 years). The disease was classified according to the 1987 UICC system. There were 10 supraglottic cancers (3 T2N0, 1 T2N1, 3 T3N0, 2 T3N1, 1 T3N2), and 19 glottic cancers (12T2N0, 1T2N1, 4T3N0, 2T3N1). Two subtypes of supracricoid partial laryngectomy were performed, one with epiglottis preserved and reconstructed with cricohyoidepiglottopexy (CHEP), the other involved epiglottic resection and reconstructed with cricohyoidopexy (CHP). RESULTS: The voice was good in all cases. Twenty-seven cases were decannulated (93.1%). All cases had overcome the aspiration by practice. The overall 3-year and 5-year survival rates were 89.7% and 75.9%. CONCLUSION: Supracricoid partial laryngectomy was appropriate for selected supraglottic and glottic cancers.

Adult↗