Biomedical subjects

Rong Guo

Publications and source records attributed to Rong Guo.

At least 37 records · Page 2Linked to original sources

PubMed2005

Interaction between morin and sodium dodecyl sulfate (SDS) micelles.

Electronic absorption spectra, fluorescence emission spectra, ATR-FTIR spectra, cyclic voltammetric measurements, and ab initio quantum calculation are used to study the properties of morin in SDS micelles of different microstructures and microenvironments and to gain the information about the binding of morin with the SDS micelles. Morin can be located in the SDS micelles with its phenyl group (deviating by 38.98 degrees from the planarity), which leads to the increase of the planarity and the extension of pi conjugation of the whole molecule. The embedment of two hydroxyl groups on the phenyl into a more hydrophobic microenvironment makes the oxidation peak of morin move to a higher potential with a decreased peak current. The binding constant (K) and the distribution coefficient (P) of morin in the spherical SDS micelle are larger than those in the rodlike SDS micelle. The binding of morin with SDS micelle is a spontaneous (DeltaG < 0) and exothermic process (DeltaH < 0), and the hydrophobic force is the main driving force for its solubilization.

Antioxidants↗

PubMed2005

The influence of sodium dodecyl sulfate/benzyl alcohol/H2O system on the photoisomerization of trans-stilbene.

Photoisomerization of trans-stilbene (TS) was investigated in sodium dodecyl sulfate (SDS)/benzyl alcohol (BA)/H(2)O systems in order to establish the relationship between the reaction yields and the compositions and structures of molecular organized assemblies. The results show that, in SDS/BA/H(2)O systems with the structures of oil in water microemulsions, bicontinuous microemulsions, and hexagonal liquid crystals, the reaction yields are much larger than those in benzyl alcohol, both with and without the photosensitizer 9,10-anthracenedicarbonitrile. However, SDS/BA/H(2)O water in oil microemulsion and lamellar liquid crystal can obviously catalyze the photoisomerization of TS only when the photosensitizer is not present. The yield is increased with the increase in H(2)O content or with the decrease in BA content.

Journal Article↗

PubMed2005

[Effect of vascular endothelial growth factor antisense oligodeoxynucleotides on angiogenesis in lymphoma of nude mice].

BACKGROUND & OBJECTIVE: It has been reported that vascular endothelial growth factor (VEGF) plays an important role in progression of lymphoma, and lymphoma with high level of VEGF is likely to metastasise at early stage. This study was to explore effects of antisense oligodeoxynucleotides (ASODN) targeting VEGF on angiogenesis of lymphoma through in vitro, and in vivo experiments. METHODS: Human lymphoma cell line Namalwa cells were incubated with VEGF ASODN (final concentrations were 10, 20, and 30 micromol/L, respectively), or scrambled sequence for 24 h or 48 h. VEGF mRNA expression in treated cells was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and its protein expression was detected by SP immunohistochemistry. After incubation of 30 micromol/L of VEGF ASODN, 30 micromol/L of scrambled sequence, and PBS as negative control, Namalwa cells were injected into nude mice. Diameters of tumors in ASODN group (6 mice), scrambled sequence group (6 mice), and PBS group (4 mice) were measured, microvessel density (MVD) was detected via immunohistochemistry. RESULTS: Expression of VEGF mRNA in cells treated with 10, 20, and 30 micromol/L of ASODN were 1.28, 0.86, and 0.47, respectively; those of PBS-treated cells, and scrambled sequence-treated cells were 1.79, and 1.84. Positive rate of VEGF protein in ASODN-treated cells was significantly lower than those in scrambled sequence-treated cells, and PBS-treated cells (23.3% vs. 46.9%, and 47.8%, P<0.05). MVDs of ASODN group, scrambled sequence group, and PBS group were 12.26+/-0.78, 23.92+/-1.14, and 24.13+/-1.21, respectively. CONCLUSION: VEGF ASODN can down-regulate expression of VEGF, and suppress angiogenesis in lymphoma.

Animals↗

PubMed2005

[Study of diffusion of muscone in different inclusion complexes and liposome through mouse (correction of rat) skin in vitro].

OBJECTIVE: To compare the penetrating rate of muscone in different inclusion complexes and liposome. METHOD: The transdermal effect of muscone in different inclusion complexes and liposome was studied comparatively on mouse [corrected] skin with 40% EtOH as the absorption solution and with an improved Franz diffuse cell. RESULT: Among the different inclusion complexes and liposome, the penetrating rate of muscone in the HP-beta-cyclodextrin inclusion and the liposome were higher than muscone, and that of muscone in the beta-cyclodextrin inclusion is the lowest. CONCLUSION: The HP-beta-cyclodextrin inclusion and the liposome can hence the muscone transdermal speed.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed2005

[Biological activity of C II TA anti-sense RNA--a novel approach to inhibition of rejection in transplantation].

Allo-cell transplant rejection is associated with class II major histocompatibility complex (MHC II), while its transactivator (namely C II TA) regulates MHC II molecules expression strictly and exclusively. The aim of this study was to investigate the inhibiting effect of C II TA anti-sense RNA on MHC II expression. The cDNA for anti-sense RNA recognizing the 114-523 sequence of C II TA (arC II TA) was obtained from Raji cell by RT-PCR, and then inserted into the pcDNA3.1B plasmid (pcDNA3.1B-arC II TA, pD-arC II TA). Raji cells were transfected stably with pD-arC II TA, classic MHC II antigen (HLA-DR, -DP, -DQ) expression was assayed by flow cytometry (FCM). mRNA abundance of C II TA, invariant chain and classic MHC II were detected by RT-PCR. The results showed that compared with control (sense C II TA), the expression inhibition of HLA-DR, -DP, -DQ on pD-arC II TA positive Raji cell was 65.93%, 54.14%, 68.32% respectively. The mRNA contents of C II TA, invariant chain and classic MHC II also decreased. In conclusion, arC II TA inhibited C II TA and thus the family of MHC II molecules were regulated by it, therefore these results provide a novel approach for the control of graft versus host diseases.

Cell Line, Tumor↗

PubMed2004

Attenuation of GVHD for allo-bone marrow transplantation recipient by FasL-Fas pathway in an H-2 haplotype disparate mouse combination.

In order to explore a new special and effective way to prevent graft versus host disease (GVHD) after allogenic bone marrow transplantation (allo-BMT), the stem cell antigen-1 (Sca-1) + early hematopoietic cells (EHC) from BALB/c mouse (H-2d) were introduced with exogenous mouse Fas ligand (mFasL) cDNA gene by the retrovirus-mediated gene transfer and expanded for one week, and then they were co-cultured with the spleen mononuclear cells (SMNC) from BAC mouse (H-2dxb) as one way mixed lymphocyte reaction (OWMLR). The cytotoxicity of treated BAC mouse SMNC against Na2 51CrO4 labeling SMNC from BALB/c mouse was observed. The bone marrow mononuclear cells (BMMNC) from BAC mouse treated by the above methods were transplanted into lethally-irradiated congenic BALB/c mice to observe the occurrence of GVHD. The results showed that the SMNC from BAC mouse after OWMLR with exogenous mFasL cDNA gene-transduced hematopoietic cells (HC) from BALB/c mouse in a ratio of 1 to 5 exhibited an obvious inhibition of the cytotoxicity against the BALB/c mouse spleen cells at different effector/target ratios as compared to the control group (P<0.01). The grade I GVHD or no GVHD and the 80% survival rate at day 60 post-BMT were observed in the BALB/c mouse receiving BAC mouse BMMNC treated with similar way, while the grade II - III GVHD and the 20% survival rate were noted in the control group (P<0.01). It is suggested that the attenuation of GVHD in allo-BMT recipient could be successfully achieved through FasL-Fas pathway in an H-2 haplotype disparate mouse combination.

Animals↗

PubMed2004

Expression of CII TA gene in five human malignant hematological cell lines and its significance.

The role of MHC class II transactivator (C II TA) in constitutive or IFN-gamma inducible expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and C II TA protein was detected by Western blot, immunohistochemistry and flow cytometry. The expression of C II TA gene was determined by RT-PCR. The capability of peripheral blood T cell reaction stimulated by tumor cells was monitored by mixed lymphocyte reaction. It was found that the HLAII-positive tumor cells expressed the C II TA quite well, and the expression of HLA I + II was increased in the tumor cells with constitutive or inducible expression of C II TA after induced by IFN-gamma. The tumor cells which did not express C II TA after induced by IFN-gamma were not response to the expression of HLA II promoted by IFN-gamma. It suggests a correlation between the inability of some malignant hematological cell lines in response to IFN-gamma for HLA expression and the deficiency in the inducible expression of C II TA, indicating C II TA might take part in the regulation of HLA I + II expression in the tumor cells, which might play an important role in tumor immunologic escape.

Animals↗

PubMed2004

[The expression and significance of major histocompatibility complex II transactivator gene in five human malignant hematological cell lines].

OBJECTIVE: To investigate the role of major histocompatibility complex (MHC) II transactivator in constitutive or interferon (IFN)-gamma inducible expression of MHC molecules in human malignant hematological cell lines. METHODS: The expression of MHC molecules and MHC class II transactivator (CIITA) protein were detected with Western blot, immunohistochemistry and flow cytometry. The expression of CIITA gene was determined with RT-PCR. T cell expressing interleukin (IL)-2 mRNA was induced by Jurkat with mixed lymphocyte reaction. RESULTS: It was found that the MHCII-positive tumor cells expressed the CIITA quite well, and IFN-gamma could induce the expression of MHCI + II only if the tumor cells were able to express CIITA in an IFN-gamma induced manner (20%, 42% for Jurkat cells respectively), while T cell expressed more IL-2 mRNA (51 times) in the case of Jurkat after induction with IFN-gamma. CONCLUSIONS: It is suggested that there is a correlation between the inability of the tumor cells in response to IFN-gamma for MHC expression and the deficiency in the inducible expression of CIITA. This might be due to immune sneaking through the tumor cells to some extent.

Blotting, Western↗

PubMed2004

[Inhibiting effect of vascular endothelial growth factor (VEGF) antisense oligodeoxynucleotides on VEGF expression in U937 cell].

To study the effect of VEGF fully phosporothioated antisense oligodeoxynucleotide (VEGF-ASODN) on VEGF expression in acute monocyte leukemic cell line U937 in vitro, U937 cells were incubated with VEGF-ASODN at concentrations of 10, 20 and 30 micro mol/L or scrambled sequence as compared with negative control. The expression of VEGF mRNA was measured by semi-quantitative RT-PCR. The expression of VEGF protein was measured by Western blot. The result showed that VEGF-ASODN had obviously inhibitive effect on expression of VEGF in U937 cell, as compared with scrambled sequence and negative control (P < 0.05). Scrambled sequence group had no significant difference compared with negative control group (P > 0.05). It is concluded that the expressions of VEGF mRNA and protein in leukemic cell line U937 are down-regulated by VEGF-ASODN.

Humans↗

PubMed2004

[Study on the reaction between cobalt tetrasulphonated phthalocyanine and sodium sulfide].

A new method which uses multi-wave number and double-parameter to analyse the UV-Vis. spectra is proposed to determine the composition and stabilization constants of coordination compounds. With this method, the reaction of cobalt tetrasulphonated phthalcyanine [CoTsPc] and sodium sulfide [Na2S] was studied. The result shows that pH of the medium has great effect on the reaction. A five coordinated compound Co(II)TsPc(HS) was formed at pH = 7.0. The equilibrium constants and thermodynamics are reported for the reaction under that condition. At higher pH, a redox-reaction took place and a five coordinated compound with the oxidation number I for cobalt [SCo(I)TsPc] was found.

Cobalt↗

PubMed2003

Effects of a bolaamphiphile on the structure of phosphatidylcholine liposomes.

This paper describes the morphological characterization of aqueous dispersions of PC amphiphiles and bolaamphiphile AEC by microscopy, the liposomal membrane fluidity, and the zeta potential. Results indicate that the bolaamphiphile AEC can be included within conventional egg-PC liposome bilayers. This behavior could be due to their preference for the stretched conformation within the PC membranes.

Drug Carriers↗

PubMed2003

Regulation of fibroblastic growth factor 23 expression but not degradation by PHEX.

Inactivating mutations of Phex cause X-linked hypophosphatemia (XLH) by increasing levels of a circulating phosphaturic factor. FGF23 is a candidate for this phosphaturic factor. Elevated serum FGF23 levels correlate with the degree of hypophosphatemia in XLH, suggesting that loss of Phex function in this disorder results in either diminished degradation and/or increased biosynthesis of FGF23. To establish the mechanisms whereby Phex regulates FGF23, we assessed Phex-dependent hydrolysis of recombinant FGF23 in vitro and measured fgf23 message levels in the Hyp mouse homologue of XLH. In COS-7 cells, overexpression of FGF23 resulted in its degradation into N- and C-terminal fragments by an endogenous decanoyl-Arg-Val-Lys-Arg-chloromethyl ketone-sensitive furin-type convertase. Phex-dependent hydrolysis of full-length FGF23 or its N- and C-terminal fragments could not be demonstrated in the presence or absence of decanoyl-Arg-Val-Lys-Arg-chloromethyl ketone in COS-7 cells expressing Phex and FGF23. In a reticulolysate system, apparent cleavage of FGF23 occurred with wild-type Phex, the inactive Phex-3'M mutant, and vector controls, indicating nonspecific metabolism of FGF23 by contaminating enzymes. These findings suggest that FGF23 is not a direct Phex substrate. In contrast, by real-time reverse transcriptase PCR, the levels of fgf23 transcripts were highest in bone, the predominant site of Phex expression. In addition, Hyp mice displayed a bone-restricted increase in fgf23 transcripts in association with inactivating Phex mutations. Increased expression of fgf23 was also observed in Hyp-derived osteoblasts in culture. These findings suggest that Phex, possibly through the actions of unidentified Phex substrates or other downstream effectors, regulates fgf23 expression as part of a potential hormonal axis between bone and kidney that controls systemic phosphate homeostasis and mineralization.

Animals↗

PubMed2003

[Apoptosis of human lung cancer cells induced by activated peroxisome proliferator-activated receptor-gamma and its mechanism].

OBJECTIVE: To explore the effects of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) on the growth of human lung cancer cell lines and its possible mechanism. METHODS: Human non-small cell lung cancer (NSCLC) cells of the A549 line and human small cell lung cancer (SCLC) of the LTEP-P line were cultured and were divided into 3 groups respectively: control group, 15d-PGJ(2) group (15d-PGJ(2), a PPAR-gamma activator, was added), and ciglitazone group (ciglitazone, am antidiabetic drug, was added). Twenty-four, forty-eight, and seventy-two hours later, nested RT-PCR was used to detect t the expression of PPAR-gamma mRNA, Western blotting technique was used to detect the expression of PPAR-gamma protein, MTT staining was used to observe the proliferation of cells induced by PPAR-gamma agonists, TUNEL method was used to observe the apoptosis of cells affected by the ligands of PPAR-gamma, the expressions of bax, and bcl-2 mRN and proteins were examined by in situ hybridization and immunohistochemistry, and the expression of caspase-3 was detected by immunohistochemistry. RESULTS: PPAR-gamma was expressed in the two lung cancer cell lines. The cell proliferation was inhibited by 15d-PGJ(2) and ciglitazone, especially the former, in dose-dependent and time-dependent manners. The apoptosis rates were (1.9 +/- 0.5)%, (9.8 +/- 1.5)%, and (5.6 +/- 1.1)% respectively in the control, 15d-PGJ(2), and ciglitazone groups with a significant difference between ant 2 groups (all P < 0.05). The expression rate of bax were (9,2 +/- 1.5)%, (63 +/- 10)%, and (31 +/- 6)% respectively in the control, 15d-PGJ(2), and ciglitazone groups with a very significant difference between ant 2 groups (all P < 0.01). he expression rate of bcl-2 were (18 +/- 3)%, (36 +/- 9)%, and (33 +/- 7)% respectively in the control, 15d-PGJ(2), and ciglitazone groups with a very significant difference between the control group and any of the agonist-treated groups (all P < 0.01) and without significant difference between the two treated groups. The expression rates of caspase-3 were (6.5 +/- 1.0)%, (65 +/- 11)%, and (40 +/- 7)% respectively in the control, 15d-PGJ(2), and ciglitazone groups with a significant difference between any 2 group (all P < 0.01). The caspase-3 level was positively correlated with the level of apoptosis. CONCLUSION: Activated by ligands, PPAR-gamma remarkably inhibits the growth of human lung cancer cells through inducing apoptosis. Caspase-3 and bax/bcl-2 play a role in this process, PPAR-gamma is so important in the pathogenesis and/or progression of lung cancer that it may be a novel therapeutical target against lung cancer.

Apoptosis↗

PubMed2003

[Cloning and biological activities of riboenzymes against major histocompatibility complex class II transactivator].

OBJECTIVE: To investigate the cloning and biological activities of riboenzymes against major histocompatibility complex (MHC) class II transactivator (CIITA) so as to explore the feasibility of using hammerhead riboenzyme to create immune tolerance. METHODS: Three riboenzymes against MHC CIITA were synthesized and their activities were evaluated in vitro. Rz464, the riboenzyme with a better digestion effect, was inserted into the vector pIRES2-EGFP (then called pRz464). Human B lymphoma cells of Daudi line were cultured and transfected with pRz464 (then called pRz464-D). Cultured Daudi cells transfected with riboenzyme without the ability against CIITA (Rz-D) were used as control group. The expressions of classic MHC CIITA (HLA-DR, DP, and DQ) on the surface of Daudi cells before and after transfection were examined by flow cytometry. RESULTS: The expressions of HLA-DR, DP, and DQ on the surface of cultured Daudi cells (Rz-D) were 97.9 +/- 0.8%, 94.3 +/- 1.1%, and 54.4 +/- 3.1% respectively. The expressions of HLA-DR, DP, and DQ were inhibited by 88.4%, 83.5%, and 93.4% respectively on the surface of pRz464-D cells. CONCLUSION: The hammerhead riboenzyme Rz464 inhibits the expression of CIITA mRNAs, thus inhibiting the expression of MHC II molecules. It may be used in antigen-specific tolerance induction in allo-transplantation.

Cloning, Molecular↗

PubMed2003

In vitro biological activity of anti-C II TA hammerhead ribozyme--a novel approach for autoimmune diseases.

This study investigated the feasibility of using an hammerhead ribozyme against C II TA, a major regulator of MHC II antigens, to repress the expression of MHC II molecules on Hela cells. A hammerhead ribozyme (Rz464) specific to 463-465 GUC triplet of C II TA and its target gene were transcribed, then mixed up and incubated in vitro. The cleavage products were analyzed by PAGE and silver-staining. Rz464 was then inserted into the pIRES2-EGFP vector (pRz464). Stable transfectants of Hela with pRz464 were tested for class II MHC induction by recombinant human interferon-gamma (IFN-gamma). mRNA of C II TA was measured by RT-PCR. Our results showed that Rz464 could exclusively cleave C II TA RNA. When induced with IFN-gamma, the expression of HLA-DR, -DP, -DQ on pRz464+ Hela was induced, and the mRNA content of C II TA decreased too. It is concluded that Rz464 could inhibit C II TA and thus the family of genes was regulated by C II TA:MHC II molecules. These results provided insight into the future application of Rz464 as a new nucleic acid drug against auto-immune diseases.

Autoimmune Diseases↗

PubMed2003

Ssh10b, a conserved thermophilic archaeal protein, binds RNA in vivo.

Proteins of the Sac10b family, which is highly conserved among hyperthermophilic archaea, have been regarded as DNA-binding proteins. Based on their in vitro DNA-binding properties, these proteins are thought to be involved in chromosomal organization or DNA repair/recombination. We show that Ssh10b, a member of the Sac10b family from Sulfolobus shibatae, bound with similar affinities to double-stranded DNA, single-stranded DNA and RNA in vitro. However, the protein was exclusively bound to RNA in S. shibatae cells, as revealed by in vivo UV cross-linking and co-immunoprecipitation. Ribosomal RNAs were among the RNA species co-immunoprecipitated with Ssh10b. Consistent with this observation, Ssh10b was co-purified with ribosomes under low salt conditions. Furthermore, we demonstrate by UV-cross-linking hybridization that, when the cells were irradiated with UV, Ssh10b became cross-linked to 16S, 23S rRNAs and mRNAs. Our data indicate that RNA is the physiological binding target of the Sac10b family.

Archaeal Proteins↗

PubMed2003

Crystal structure of a DNA binding protein from the hyperthermophilic euryarchaeon Methanococcus jannaschii.

The Sac10b family consists of a group of highly conserved DNA binding proteins from both the euryarchaeotal and the crenarchaeotal branches of Archaea. The proteins have been suggested to play an architectural role in the chromosomal organization in these organisms. Previous studies have mainly focused on the Sac10b proteins from the crenarchaeota. Here, we report the 2.0 A resolution crystal structure of Mja10b from the euryarchaeon Methanococcus jannaschii. The model of Mja10b has been refined to an R-factor of 20.9%. The crystal structure of an Mja10b monomer reveals an alpha/beta structure of four beta-strands and two alpha-helices, and Mja10b assembles into a dimer via an extensive hydrophobic interface. Mja10b has a similar topology to that of its crenarchaeota counterpart Sso10b (also known as Alba). Structural comparison between the two proteins suggests that structural features such as hydrophobic inner core, acetylation sites, dimer interface, and DNA binding surface are conserved among Sac10b proteins. Structural differences between the two proteins were found in the loops. To understand the structural basis for the thermostability of Mja10b, the Mja10b structure was compared to other proteins with similar topology. Our data suggest that extensive ion-pair networks, optimized accessible surface area and the dimerization via hydrophobic interactions may contribute to the enhanced thermostability of Mja10b.

Amino Acid Motifs↗

PubMed2003

Repression of allo-cell transplant rejection through CIITA ribonuclease P+ hepatocyte.

AIM: Allo-cell transplant rejection and autoimmune responses were associated with the presence of class II major histocompatibility complex (MHC II) molecules on cells. This paper studied the effect of Ribonuclease P (RNase P) against CIITA, which was a major regulator of MHCII molecules, on repressing the expression of MHCII molecules on hepatocyte. METHODS: M1-RNA is the catalytic RNA subunit of RNase P from Escherichia coli. It were constructed that M1-RNA with guide sequences (GS) recognizing the 452, 3408 site of CIITA by PCR from pTK117 plasmid, then were cloned into the EcoRI/BglII or EcoR//SalIsite of vector psNAV (psNAV-M1-452-GS, psNAV-M1-3408-GS) respectively. The target mould plate (3176-3560) of CIITA was obtained from Raji cell by RT-PCR, and then inserted into the XhoI/EcoRIof pGEM-7zf(+) plasmid (pGEM-3176). These recombinant plasmids were screened out by sequence analysis. psNAV-M1-452-GS, psNAV-M1-3408-GS and its target RNA pGEM-3176 were transcribed and then mixed up and incubated in vitro. It showed that M1-3408-GS could exclusively cleave target RNA that formed a base pair with the GS. Stable transfectants of hepatocyte cell line with psNAV-M1-3408-GS were tested for expression of class II MHC through FCM, for mRNA abundance of MHCII, Ii and CIITA by RT-PCR., for the level of IL-2 mRNA on T cell by mixed lymphocyte reaction. RESULTS: When induced with recombinant human interferon-gamma (IFN-gamma), the expression of HLA-DR, -DP, -DQ on psNAV-M1-3408-GS(+) hepatocyte was reduced 83.27 %, 88.93 %, 58.82 % respectively, the mRNA contents of CIITA, HLA-DR, -DP, -DQ and Ii decreased significantly. While T cell expressed less IL-2 mRNA in the case of psNAV-M1-3408-GS(+) hepatocyte. CONCLUSION: The Ribonuclease P against CIITA-M1-3408-GS could effectively induce antigen-specific tolerance through cleaving CIITA. These results provided insight into the future application of M1-3408-GS as a new nucleic acid drug against allo-transplantation rejection and autoimmune diseases.

Base Sequence↗