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Biomedical subjects

G Yuan

Publications and source records attributed to G Yuan.

At least 19 recordsLinked to original sources
PubMed2006

Co-transplantation of bone marrow stromal cells transduced with IL-7 gene enhances immune reconstitution after allogeneic bone marrow transplantation in mice.

Allogeneic bone marrow transplantation (allo-BMT) is followed by a period of profound immune deficiency, which results in significant susceptibility to infections and limits the extensive application of this approach in clinic. Here, we transduced human interleukin-7 (IL-7) gene into donor-derived bone marrow stromal cells (MSCs) using adenovirus vector, and transplanted this gene-engineered MSCs (MSC-IL-7) into lethally irradiated C57BL/6 mice to investigate their effects on immune reconstitution following allo-BMT. Recipient mice receiving MSC-IL-7 cells plus T-cell-depleted bone marrow cells of BALB/c mice showed a significant increase in thymopoiesis and homeostatic expansion of peripheral T lymphocytes. Furthermore, injection of MSC-IL-7 cells following allo-BMT protected the host from the lethality caused by acute graft-versus-host disease (GVHD) and prevented the occurrence of GVHD induced by transplanted T cells. Thus, the use of MSC-IL-7 cells may be therapeutically useful for enhancing immune reconstitution without aggravating GVHD in allo-BMT mice.

Adenoviridae↗
PubMed2000

A convenient method for the synthesis of DNA-recognizing polyamides in solution.

A convenient method for the synthesis of polyamides containing N-methylpyrrole (Py) and N-methylimidazole (Im) in solution has been developed. Most of the building blocks have been prepared by a haloform reaction in a simple way that column chromatography can be avoided. By use of the DCC/HOBT coupling reaction, the building blocks prepared have been effectively connected to construct a variety of subchains and polyamides without employing amino protection and deprotection. By use of the present method, an eight-ring polyamide, PyPyPyPygammaPyImImPybetaDp (gamma is gamma-aminobutyric acid, beta is beta-alanine, Dp is N, N-dimethylpropyldiamine), has been synthesized by the coupling of two four-ring subchains in one step.

DNA↗
PubMed2000

A clinical investigation on garlicin injectio for treatment of unstable angina pectoris and its actions on plasma endothelin and blood sugar levels.

To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used in 21 cases of the control group. The results showed that the total effective rates in improving symptoms and electrocardiogram after garlicin treatment were respectively 82% and 62%, and that the plasma endothelin and blood sugar levels were markedly lowered in cases with hyperglycemia.

Aged↗
PubMed2000

[Studies on chemical constituents of the fruits of Rosa bracteata var. bracteata].

The chemical constituents of Rosa bracteata Wendl. var. bracteata were studied for the first time. Six compounds were isolated from the fruits of the plant, and four of them have been identified as 5-hydroxymethyl furfural, 5-acetoxymethyl furfural, beta-sitosterol, oleanolic acid. 5-hydroxymethy furfural and 5-acetoxymethyl furfural were obtained from genus Rosa L. for the first time. Otherwise, a white wax was obtained by silica gel column chromatography, from which four main constituents were identified as nonadecene, n-docosane, hentriacontane and hexatriacontane by GC-MS.

Chromatography, Gas↗
PubMed1999

[The treatment effect of ribavirin to hemorrhagic fever with renal syndrome on the kinetics of serum creatine phosphate kinase isoenzyme].

OBJECTIVE: To study the effect of ribavirin treatment on kinetics of serum creatine phosphate kinase isoenzyme(CK-MB) of patients with hemoarrhagic fever with renal syndrome(HFRS). METHODS: CK-MB levels in 155 HFRS patients treated with larger dose of ribavirin and with routine therapeutic dose were observed dynamicaly, using randomly controlled double-blind method. In addition, CK-MB levels in different disease phases and different clinical types of HFRS were compared. RESULTS: The results showed that CK-MB levels were significantly increased in febrile phase and decreased gradually to normal during convalescent phase in both groups, but in febrile phase, CK-MB levels in ribavirin-treated group and control group were 55.25 +/- 18.25 IU/L and 69.63 +/- 23.52 IU/L, respectively, the treated group had a lower level (P < 0.05). The severe and critical group treated by ribavirin showed a lower CK-MB level of 47.74 +/- 24.82 IU/L, while the control group showed a higher level of 66.08 +/- 25.01 IU/L(P < 0.05). CONCLUSION: These results indicated that an early application of large dose of ribavirin in treatment of HFRS can reduce the serum CK-MB levels in patients with HFRS.

Adult↗
PubMed1999

Cloning and characterization of human guanine deaminase. Purification and partial amino acid sequence of the mouse protein.

Mouse erythrocyte guanine deaminase has been purified to homogeneity. The native enzyme was dimeric, being comprised of two identical subunits of approximately 50,000 Da. The protein sequence was obtained from five cyanogen bromide cleavage products giving sequences ranging from 12 to 25 amino acids in length and corresponding to 99 residues. Basic Local Alignment Search Tool (BLAST) analysis of expressed sequence databases enabled the retrieval of a human expressed sequence tag cDNA clone highly homologous to one of the mouse peptide sequences. The presumed coding region of this clone was used to screen a human kidney cDNA library and secondarily to polymerase chain reaction-amplify the full-length coding sequence of the human brain cDNA corresponding to an open reading frame of 1365 nucleotides and encoding a protein of 51,040 Da. Comparison of the mouse peptide sequences with the inferred human protein sequence revealed 88 of 99 residues to be identical. The human coding sequence of the putative enzyme was subcloned into the bacterial expression vector pMAL-c2, expressed, purified, and characterized as having guanine deaminase activity with a Km for guanine of 9.5 +/- 1.7 microM. The protein shares a 9-residue motif with other aminohydrolases and amidohydrolases (PGX[VI]DXH[TVI]H) that has been shown to be ligated with heavy metal ions, commonly zinc. The purified recombinant guanine deaminase was found to contain approximately 1 atom of zinc per 51-kDa monomer.

Amino Acid Sequence↗
PubMed1999

Study on relationship between anticardiolipin antibody and cerebrovascular diseases.

Serum anticardiolipin antibody (ACA) was measured in 91 patients with cerebral infarction (CI), 42 patients with cerebral hemorrhage (CH) and 30 healthy controls. The results showed that the ACA in CI and CH patients was significantly higher than in controls and IgG-ACA was the most important isotype. Stroke in ACA positive group tended to be recurrent and of multi-focuses. Positive rate of IgG-ACA reached its peak within the first week after stroke onset. The results suggested that ACA was an independent risk factor in CI and CH and might be valuable in stroke prediction.

Aged↗
PubMed1999

Epidermal growth factor receptor participates in growth hormone signaling pathway in cardiac myocytes of neonatal rat.

OBJECTIVE: To examine whether growth hormone (GH) promotes the phosphorylation of epidermal growth factor (EGF) receptor and to elucidate the mechanisms by which EGF receptors were transactivated by GH stimulation. METHODS: Cultured cardiac myocytes were stimulated by GH directly or pretreated with inhibitors before GH stimulation. The phosphorylations of EGF receptor and JAK2 were examined with immunoprecipitation followed by Western blotting using anti-phosphotyrosine antibody (4G10). The activities of extracellular signal-regulated kinases (ERKs) were assayed with the method of MBP-containing gel. RESULTS: GH stimulated phosphorylation of EGF receptor in a time-dependent manner. Tyrphostin AG1478, a selective inhibitor of EGF receptor, strongly suppressed GH-induced ERK activation, while tyrphostin AG1295, a selective inhibitor of PDGF receptor, had no effects on the activation of ERKs stimulated by GH in cardiac myocytes. In addition, GH induced tyrosine phosphorylation of JAK2, a cytoplasmic protein tyrosine kinase, in cardiac myocytes. Moreover, tyrphostin B42, an inhibitor of JAK2 suppressed GH-induced phosphorylation of EGF receptor as well as GH-induced activation of ERKs in cardiac myocytes. CONCLUSIONS: GH evokes the phosphorylation of EGF receptor in cardiac myocytes through activating JAK2. Phosphorylated EGF receptor plays a critical role in GH signaling pathway leading to ERK activation in cardiac myocytes.

Animals↗
PubMed1999

[Expression of interleukin-6 and its receptors in peripheral blood of patients with systemic lupus erythematosus].

OBJECTIVE: To investigate the level of interleukin-6 (IL-6) and soluble-IL-6 receptor (sIL-6R) in serum of patients with systemic lupus erythematosus (SLE) and its correlation with disease activity and to explore IL-6 signal transduction pathways in SLE patients. METHODS: By using MTT colorimetry and ELISA, the levels of IL-6 and sIL-6R in serum from 16 patients with SLE (9 active, 7 inactive), 17 with active rheumatoid arthritis (RA) and 29 controls were measured. The expressions of acute phase reaction factor (APRF) in peripheral blood mononuclear cells (PBMCs) were also detected by using electrophoresis mobility shift assays (EMSA) after the PBMCs were isolated and then stimulated by IL-6. RESULTS: Serum IL-6 and sIL-6R levels in active SLE patients were significantly higher than those in normal controls (P < 0.01), but were significantly lower than those in active RA patients (P < 0.01). Serum IL-6 rather than sIL-6R level in active SLE patients was significantly higher than that in inactive ones (P < 0.01). Serum IL-6 was correlated positively with the anti-dsDNA antibody (r = 0.658, P < 0.01), but not with CRP (r = 0.041, P > 0.05). There were no expression of APRF in PMNC from SLE patients and 8 normal controls, whereas PMNC from 11 RA patients expressed APRF activity (11/17). CONCLUSION: The level of IL-6 is a useful parameter for monitoring disease activity of SLE. In active SLE, no significant elevation of serum sIL-6R and no expression of APRF in PMBCs may be responsible for mild CRP elevation.

Adolescent↗
PubMed1999

[Kinetics of the Ca(2+)-activated K+ channel in Ca2+ induced cortex neurons damage].

Ca(2+)-activated K+ channels were studied by using the patch clamp technique of single channel recordings from the primary culture fetal SD rat cortex neurons. Besides their physiologic characters, the effects of increasing cytosolic and cytoplasmic Ca2+ triggered neuronal damage were also studied. The results showed that Kca with conductance around 170PS was predominant in the rat cortex neurons. These channels almost did not open at physiologic intracellular free Ca2+ concentration (10(-8) mol/L), but was extremely activated at intracellular free Ca2+ concentration (10(-6) mol/L). So the open probabilities of the KCa in the cortex neurons obviously depended on the concentration of cytoplasmic Ca2+ and membrane potential. The KCa activated by increasing of intracellular Ca2+ during the early stage of anoxia may be a protective reaction of ischemic neurons.

Animals↗
PubMed1998

[Molecular analysis of HLA-DR beta polymorphism in Han nationality patients with rheumatoid arthritis].

OBJECTIVE: To analyze the molecular basis for HLA-DR associations with rheumatoid arthritis(RA) in the han nationality of Chinese population. METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques were used to dertermine DRB1 alleles in 35 unrelated patients with RA and 100 healthy controls from the Han nationality. RESULTS: The frequency of DR4(DRB1 * 04) was 51.4% in RA patients and 24.0% in the healthy controls(P < 0.01, RR = 3.3). There was a significant increase in the presence of the amino acid sequences QKRAA or QRRAA both in the RA patients overall compared with the healthy group(65.7% vs 30.0%, P < 0.001) and in DR4+ RA patients compared with DR4+ healthy individuals(100% vs 75.0%, P < 0.05). Substitution of residues in QKRAA, V85 and G86 appeared to correlate with relative risk for RA, among the subjects having 0-1 amino acid substitution, RA occurred in 48.8%, whereas in subjects with 2-3 amino acid changes, RA was present in only 16.7%. CONCLUSION: These results suggest that DR4 is strongly associated with RA in the Han nationality, and the dominant effect that determines susceptibility to RA is associated with QKRAA or QRRAA as well as V85 and G86.

Adult↗
PubMed1997

[DNA typing for HLA-DR and HLA-DQ alleles in Chinese patients with rheumatoid arthritis].

We analysed the associations of DR and DQ alleles with rheumatoid arthritis (RA) in Han nationality of China. PCR-RFLP technique was used to determine DRB1, DQA1 and DQB1 alleles in 35 unrelated patients with RA and 100 healthy controls from the Hans. The frequency of DR4 was 51.4% in RA patients and 24.0% in the healthy controls (P < 0.01, RR = 3.30). Subtyping of DR4 revealed no differences in the relative distributions of the DR4 alleles between the RA group and the controls, which both were predominated by DRB1 * 0405 allele, but there was a significant increase in the absolute frequency of DRB1 * 0405 in RA patients compared with the healthy controls (31.4% vs 12.0%, P < 0.01). DQ4 (DQB1 * 04) was also increased both in the RA patients compared with the healthy controls (37.1% vs 10.0%, P < 0.001) and in DR4+ RA patients compared with DR4+ healthy ones (72.2% vs 41.6%, P = 0.0376). Further analysis showed that the haplotype DR4-DQ4 was associated with RA (RR = 5.17, P < 0.001), and that the DR4(+)-DQ4+ patients had more severe disease than the DR4- patients. These results suggest that DR4, mainly the DRB1 * 0405, is associated with RA in Han nationality, and DQ4 may play a role in DR4 conferring susceptibility to RA. The DR4-DQ4 haplotype could be taken as a predictive marker for disease severity.

Alleles↗
PubMed1997

[Properties of adherence of erythrocytes to endothelial cells in patients with ischemic stroke].

Adherence of erythrocytes to human umbilical vein endothelial cells (HUVEC) in patients with cerebral thrombosis and transient ischemic attack (TIA) were quantitatively studied in the flow chamber system, compared with that in healthy subjects. We found: (a) The adherence of erythrocytes to HUVEC in patients with cerebral thrombosis and TIA increased, compared with that in healthy subjects; (b) The adhesion of erythrocytes to HUVEC in patients with TIA was not significantly different from that of patients with cerebral thrombosis. These suggested that the increased adhesion of erythrocytes to endothelial cells might play an important role in the pathologic process of ischemic stroke.

Aged↗