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Xiang Zhang

Publications and source records attributed to Xiang Zhang.

At least 73 records · Page 4Linked to original sources
PubMed2005

A novel total synthesis of kinsenoside and goodyeroside A relying on the efficient reaction of the chiral 2(5H)-furanones.

A new total synthesis of the bioactive compounds, kinsenoside and goodyeroside A, has been accomplished from readily available starting materials. The chiral 2(5H)-furanone and its enantiomer were employed as the key chiral intermediates to construct the chiral glycosides and with the appropriate stereochemistry. The spectral data of the target compounds and their acetylated derivatives and are identical with those of the natural and corresponding acetylated products.

4-Butyrolactone↗
PubMed2004

Iodo-controlled selective formation of pyrrolidino[60]fullerene and aziridino[60]fullerene from the reaction between C6) and amino acid esters.

The reaction between glycine methyl ester and C60 can be effectively controlled by different iodo-reagents. Addition of DIB ((diacetoxyiodo)benzene) yields the 2,5-bismethoxycarbonyl pyrrolidino[60]fullerene under ultrasonic irradiation; whereas addition of DIB-iodine results in the N-methoxycarbonylmethyl aziridino[60]fullerene under ultrasonic irradiation. The reaction of sarcosine methyl ester with C60 is similar to that of glycine methyl ester under these two conditions. Addition of just iodine to a mixture of sarcosine methyl ester and C60 affords the tetra(amino)[60]fullerene epoxide C60(O)((Me)NCH2COOMe)4. Possible mechanisms are discussed.

Amino Acids↗
PubMed2004

Selective preparation of oxygen-rich [60]fullerene derivatives by stepwise addition of tert-butylperoxy radical and further functionalization of the fullerene mixed peroxides.

tert-Butylperoxy radicals add to C(60) selectively to form multi-adducts C(60)(O)(m)(OO(t)Bu)(n) (m = 0, n = 2, 4, 6; m = 1, n = 0, 2, 4, 6) in moderate yields under various conditions. Visible light irradiation favors epoxide formation. High concentration of tert-butylperoxy radicals mainly produces the hexa-homoadduct C(60)(OO(t)Bu)(6) 6; low concentration and long reaction time favor the epoxy-containing C(60)(O)(OO(t)Bu)(4) 7. The reaction can be stopped at the bis-adducts with limited TBHP. A stepwise addition mechanism is discussed involving mono-, allyl-, and cyclopentadienyl C(60) radical intermediates. m-CPBA reacts with the 1,4-bis-adduct to form C(60)(O)(OO(t)Bu)(2) and C(60)(O)(3)(OO(t)Bu)(2). The C-O bond of the epoxy ring in 7 can be cleaved with HNO(3) and CF(3)COOH. Nucleophilic addition of NaOMe to 7 follows the S(N)1 and extended S(N)2' mechanism, from which four products are isolated with the general formula C(60)(O)(a)(OH)(b)(OMe)(c)(OO(t)Bu)(d). Visible light irradiation of the hexa-adduct 6 results in partial cleavage of both the C-O and O-O bonds of peroxide moieties and formation of the cage-opened compound C(60)(O)(O)(2)(OO(t)Bu)(4). All the fullerene derivatives are characterized by spectroscopic data. A single-crystal structure has been obtained for an isomer of C(60)(O)(OH)(2)(OMe)(4)(OO(t)Bu)(2).

Journal Article↗
PubMed2004

Integrative biological analysis of the APOE*3-leiden transgenic mouse.

Integrative (or systems biology) is a new approach to analyzing biological entities as integrated systems of genetic, genomic, protein, metabolite, cellular, and pathway events that are in flux and interdependent. Here, we demonstrate the application of intregrative biological analysis to a mammalian disease model, the apolipoprotein E3-Leiden (APO*E3) transgenic mouse. Mice selected for the study were fed a normal chow diet and sacrificed at 9 weeks of age-conditions under which they develop only mild type I and II atherosclerotic lesions. Hepatic mRNA expression analysis showed a 25% decrease in APO A1 and a 43% increase in liver fatty acid binding protein expression between transgenic and wild type control mice, while there was no change in PPAR-alpha expression. On-line high performance liquid chromatography-mass spectrometry quantitative profiling of tryptic digests of soluble liver proteins and liver lipids, coupled with principle component analysis, enabled rapid identification of early protein and metabolite markers of disease pathology. These included a 44% increase in L-FABP in transgenic animals compared to controls, as well as an increase in triglycerides and select bioactive lysophosphatidylcholine species. A correlation analysis of identified genes, proteins, and lipids was used to construct an interaction network. Taken together, these results indicate that integrative biology is a powerful tool for rapid identification of early markers and key components of pathophysiologic processes, and constitute the first application of this approach to a mammalian system.

Animals↗
PubMed2004

Methods for the differential integrative omic analysis of plasma from a transgenic disease animal model.

Multitiered quantitative analysis of biological systems is rapidly becoming the desired approach to study hierarchical functional interactions between proteins and metabolites. We describe here a novel systematic approach to analyze organisms with complex metabolic regulatory networks. By using precise analytical methods to measure biochemical constituents and their relative abundance in whole plasma of transgenic ApoE*3-Leiden mice and an isogenic wild-type control group, simultaneous snapshots of metabolic and protein states were obtained. Novel data processing and multivariate analysis tools such as Impurity Resolution Software (IMPRESS) and Windows-based linear fit program (WINLIN) were used to compare protein and metabolic profiles in parallel. Canonical correlations of the resulting data show quantitative relationships between heterogeneous components in the TG animals. These results, obtained solely from whole plasma analysis allowed us, in a rapid manner, to corroborate previous findings as well as find new events pertaining to dominant and peripheral events in lipoprotein metabolism of a genetically modified mammalian organism in relation to ApoE3, a key mediator of lipoprotein metabolism.

Animals↗
PubMed2004

Synovial fibroblasts infected with Salmonella enterica serovar Typhimurium mediate osteoclast differentiation and activation.

The mechanisms whereby arthritogenic organisms may induce cartilage and bone erosions in infection-triggered arthritis remain unknown. In this study, we asked whether an arthritogenic organism could contribute to osteoclast differentiation and activation through regulation of the receptor activator of NF-kappaB ligand (RANKL) in synovial fibroblasts. Rat synovial fibroblasts were infected in vitro with Salmonella enterica serovar Typhimurium and monitored over time. The expression of RANKL in resting and infected synovial fibroblasts was quantified by reverse transcription-PCR and Western blotting. Osteoclast progenitors, isolated from femurs of 8-week-old rats and cultured in the presence of macrophage colony-stimulating factor, were cocultured with either infected or noninfected synovial fibroblasts for 2 to 4 days. Differentiation and maturation of osteoclasts were determined by morphology and tartrate-resistant acid phosphatase (TRAP) staining and by a bone resorption bioassay. RANKL expression was undetectable in resting synovial fibroblasts but was dose-dependently upregulated in cells after Salmonella infection. Osteoprotegerin was constitutively expressed by synovial fibroblasts and was not upregulated by infection. Further, we observed the formation of multinucleated TRAP-positive cells and formation of bone resorption pits in cocultures of bone marrow-derived osteoclast precursors with synovial fibroblasts infected with Salmonella but not with heat-killed Salmonella or noninfected cells. Arthritogenic bacteria may alter bone structure via synovial fibroblast intermediaries, since infected synovial fibroblasts (i) upregulate RANKL expression and (ii) enhance osteoclast precursor maturation into multinucleated, TRAP-positive, bone-resorbing, osteoclast-like cells. These data provide a link between infection and osteoclastogenesis. A better understanding of infection-mediated osteoclast differentiation and activation may provide new therapeutic strategies for inflammatory joint disease.

Animals↗
PubMed2004

Common aspects of human and primate seronegative arthritis.

A 27-year-old female lowland gorilla developed an asymmetric oligoarthritis 3 months post-partum. There was no evidence of an antecedent gastrointestinal or genitourinary infection. Serum was negative for rheumatoid factor and antinuclear antibody. Synovial fluid revealed 2000 white blood cells with negative cultures and polarized microscopy. Studies on synoviocytes were the following: (1) FACS analysis revealed surface expression of a B27-like epitope of the cells. (2) Analysis of intracellular clearance kinetics of arthritogenic organisms showed peak intracellular colony-forming units at 48 hours after bacterial invasion, and clearance by 13 days post-invasion. (3) Interferon-y (0.1-10.0 ng/ml)accelerated intracellular microbicidal pathways in a dose-dependent fashion. These findings closely parallel those seen in human synoviocytes of patients with spondyloarthropathy. Primate and human seronegative arthritis share clinical and immunologic features, as well as aspects of host:pathogen defense mechanisms. The interplay of genetic and microbial factors underlying this arthritis appears to be conserved across these species boundaries.

Animals↗
PubMed2003

[Exogenous nitric oxide inhibits the proliferation of mouse neural progenitor cells].

OBJECTIVE: To explore the inhibitive effect of exogenous nitric oxide (NO) on the proliferation of mouse neural progenitor cells (NPCs). METHODS: NPCs were cultured in medium containing EGF, and SNP was added as a donor of NO in vitro. The concentration of NO was measured by the Griess assay; The amount of living cells was measured by MTT assay. The NPCs were induced to differentiate in medium supplemented with serum. RESULT: The NO(-)2 concentrations in the supernatants of the experimental groups 1, 2, and 3 were 64.701 +/- 0.606, 82.659 +/- 0.394 and 93.648 +/- 0.394 micro mol/L respectively, 3.099 +/- 0.420 micro mol/L in th control group. After culture with SNP for 24 hours, MTT assay showed the A values of 0.546 +/- 0.016, 0.484 +/- 0.007, and 0.357 +/- 0.007 in the experimental groups 1, 2, and 3 respectively, 0.642 +/- 0.021 in th control group (all P < 0.01). After further culture in the medium without SNP for 24 hours, MTT assay showed the A values of 1.243 +/- 0.036, 1.064 +/- 0.097, and 0.834 +/- 0.031 in the experimental groups 1, 2, and 3 respectively, 1.581 +/- 0.072 in the control group (all P < 0.01). The differences between the A values of the supernatants in the same wells filled with the medium with and without SNP were all significant (P < 0.01). In the medium with serum the NPCs still proliferated actively and differentiated into neuron and glial cell after SNP was removed. CONCLUSION: Exogenous nitric oxide inhibits the proliferation of mice NPC in vitro.

Animals↗
PubMed2003

[Endovascular treatment of intracranial aneurysms with mechanical detachable spiral-neurological].

OBJECTIVE: To evaluate the efficacy of endovascular treatment of intracranial aneurysms with mechanical detachable spiral-neurological (MDS-N). METHODS: Thirty-six patients with intracranial aneurysms were treated with MDS-N by Seldinger's approaches through femoral artery puncture. A catheter was sent into the aneurysm with proper-size MDS-N system and a spiral was pushed into the aneurysmal lumen. RESULTS: The aneurysms were completely occluded in 32 cases while partial occlusion was obtained in 4 patients. The parent arteries remained unobstructed. Follow-up of 3 - 6 months showed that all patients recovered well. No death or permanent serious complication occurred. CONCLUSION: Simple, safe, and low-cost, treatment of intracranial aneurysm with MDS-N is effective and suitable for use in larger hospital.

Adult↗
PubMed2003

Model studies of the (6-4) photoproduct photoreactivation: synthesis and photosensitized splitting of uracil oxetane adducts.

Uracil oxetane adducts, which are model compounds for the oxetane intermediates generated during the formation of (6-4) photoproducts or in their photoenzymatic repair, have been synthesized using 1,3-dimethyluracil with carbonyl compounds. On the basis of fluorescence measurements and photolysis experiments, it is demonstrated that the oxetane adducts can be split into the nucleotide base and carbonyl compounds via an electron transfer reaction from photosensitizer. The reaction is more efficient for a stronger electron donor.

DNA Adducts↗
PubMed2003

Molecular and cellular biology of new bone formation: insights into the ankylosis of ankylosing spondylitis.

One of the most distinctive features of the spondyloarthropathies is the tendency for new bone formation at sites of chronic inflammation. This is important diagnostically because radiographic evidence of ankylosis is often stated as one of the classification criteria, and it is important clinically because loss of spinal mobility over time is a major contributor to disability in this disease. The mechanisms underlying this tendency for ankylosis have not yet been defined. This review updates current concepts of the molecular and cellular basis of normal and abnormal bone formation. A better understanding of this process may open new avenues of therapeutic intervention in these chronic diseases.

Cell Lineage↗
PubMed2003

The effect of nonsense codons on splicing: a genomic analysis.

The phenomenon of nonsense-associated altered splicing raises the possibility that the recognition of in-frame nonsense codons is used generally for exon identification during pre-mRNA splicing. However, nonsense codon frequencies in pseudo exons and in regions flanking 5' splice sites are no greater than that expected by chance, arguing against the widespread use of this strategy as a means of rejecting potential splice sites.

Codon, Nonsense↗
PubMed2003

Recurrence of chronic subdural hematoma after trepanation and drainage.

OBJECTIVE: To sum up the causes of recurrence of chronic subdural hematoma (CSDH) from failure of trepanation and drainage and explore its prevention and treatment. METHODS: From October 1988 to June 2002 a total of 358 patients with CSDH were treated with trepanation and drainage in our hospital. Among them 15 patients had recurrence of CSDH after operation. The data of the 15 patients were reviewed retrospectively. RESULTS: Of the 15 patients, 13 were cured by retrepanation and redrainage, one cured by removal of hematoma by craniotomy with bone flap, and one, a 1-year old child, gave up reoperation due to severe encephalatrophy. CONCLUSIONS: Most CSDHs which recur after trepanation and drainage can be cured by retrepanation and redrainage. For the patients with repeated recurrence of CSDH removal of hematoma capsule can be considered. The causes of recurrence of CSDH are related to disease course, the thickness of hematoma capsule, the severity of encephalatraphy and whether the hematoma cavity is drained or irrigated completely, and operation methods.

Adolescent↗
PubMed2003

[Analysis of the results of 143 cases of pituitary micro-adenoma treated by Linac X-Knife stereotactic radioneurosurgery].

BACKGROUND & OBJECTIVE: The trans-sphenoid surgery was one of the main methods for the treatment of functional pituitary micro-adenoma for many years, while the development of radiosurgical techniques in recent years has given neurosurgeons new ways to treat functional pituitary micro-adenoma. This report aimed to ascertain the effectiveness of X-Knife stereotactic radioneurosurgery on pituitary micro-adenoma. METHODS: From June 1996 to June 2001, 143 cases of functional pituitary micro-adenoma were treated by X-Knife radiosurgery, in which 73 cases of secreting prolactin (PRL),54 cases of secreting growth hormone(GH), 13 cases of secreting adrenal corticotrophin hormone (ACTH), and 3 cases of secreting both PRL and GH. The radiosurgical procedure included local anesthesia administration, head-ring mounting, serial thin slice CT scanning with contrast enhancement, CT image transfer, treatment planning on the computer workstation, stereotactic localization of the target onto the Linac isocenter, and then the Linac was used to perform multiple non-coplannar arc radiation. All cases received single fraction radiosurgery. RESULTS: After X-Knife radiosurgery, follow-up ranged 3-60 months (median 38.4 month). Among those 112 cases that acquired follow-up, 78(69.7%) cases showed good clinical improvements, 10(8.9%) cases showed relatively good clinical improvements, 19(16.8%) cases showed no clinical improvement, and 5(4.6%) cases had progression of disease and enlargement of the adenoma. CONCLUSION: X-Knife radiosurgery is a safe and effective technique for the treatment of functional pituitary micro-adenoma. While for young patients, the diagnosis of pituitary micro-adenoma and use of X-Knife radiosurgery should be very cautious, otherwise hypopituitarism might be resulted.

Adenoma↗
PubMed2003

[Comparison of the intracranial pressure value in patients with hypertensive intracerebral hemorrhage treated with traditional craniotomy and puncture drainage].

OBJECTIVE: To compare the difference of intracranial pressure (ICP) in patients with hypertensive intracerebral hemorrhage (HICH) treated with two surgical procedures, traditional craniotomy and puncture drainage. METHODS: One hundred and twelve cases with HICH were randomly divided into two groups. In one group, 60 patients were operated by traditional craniotomy and in another group, 52 cases by puncture drainage and urokinase treatment. In the meantime, ICP was monitored by placing catheter in lateral ventricle on the contralateral side of the hemorrhage. ICP values were recorded after operation at once, at 24 hours, 72 hours and 1 week. RESULTS: Although all the patients showed increased ICP, the increasing degree in patients treated with traditional craniotomy had lower ICP values (P<0.05 or P<0.01). CONCLUSION: Traditional craniotomy has advantages over puncture drainage for patients with HICH at least with respect to decreasing ICP.

Adult↗
PubMed2003

Changes of metabotropic glutamate receptor subtype 1a in diffuse brain injury with secondary brain insults and the effects of 2-methyl-4-carboxyphenylglycine.

OBJECTIVE: To observe the changes of metabotropic glutamate receptor 1a in rat brain in a rodent model of diffuse head injury with secondary insults and the effects of 2-methyl-4-carboxyphenylglycine (MCPG). METHODS: Based on Marmarous rodent model of diffuse brain injury (DBI), hypotension was made by blood withdrawal as secondary brain insults (SBI). 105 male SD rats were randomized into A and B groups. The changes of mGluR(1a) in cerebral cortex were studied by immunohistochemistry and the effect of MCPG by HE. Each group was divided into different subgroups at different time after injury. RESULTS: Compared with that of sham group, the number of mGluR(1a) positive neuron increased by 12.9+/-3.2 (P<0.05) 1 day after injury in the injured cerebral cortex in DBI group. However, in DBI and SBI group there was a more significant increase in the number of mGluR(1a) positive neuron at 4 hours after injury (15.6+/-3.0, P<0.05) and then the number of mGluR(1a) positive neuron gradually decreased. Administration of MCPG reduced total cortical necrotic neurons counts on the 7th day after injury (5.21+/-2.52, P<0.05). CONCLUSIONS: Brain injury can increase the gene expression of mGluR(1a) and the role of mGluR(1a) may be a key factor in the aggravation of head injury with SBI, and that MCPG may have therapeutic potential in head injury.

Analysis of Variance↗