[Mitochondrial gene and diabetes].
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DNA, Mitochondrial↗
Biomedical subjects
R Qian
Publications and source records attributed to R Qian.
A mannose-specific lectin from Vicia villosa seeds.
A lectin specific to mannose has been purified from Vicia villosa seed by (NH4)2SO4 fractionation, GalNAc-Sepharose and Man-Sepharose affinity chromatography. It was defined as VVLM, which showed a single band on an acidic-PAGE stained with Coomassie brilliant blue. The molecular weight of VVLM was 50 kDa as determined by gel filtration on Biogel P-100 column. The VVLM molecule consists of 2 distinct subunits with apparent molecular weight of 30 kDa and 22 kDa determined by SDS-PAGE. VVLM has at least four isolectins with similar haemagglutinating activity. Its extinction coefficient is calculated as A1(1cm) = 16.4 at 280 nm. Sugars could not be detected by phenol-sulfuric acid method. The circular dichroism analysis at far UV indicated that VVLM was a beta-sheet-rich protein, and gave no alpha-helix, 69% beta-sheet, 14% beta-turn by Provencher and Glockner method. The lectin was inhibited by alpha-methyl-D-mannose at 12.5 mM and glucose or GlcNAc at 50 mM. The carbohydrate binding specificity of VVLM was investigated by using affinity chromatography on a VVLM-Sepharose column. Among various Asn-linked oligosaccharides, core structure Man alpha 1-->3(Man alpha 1-->6)Man beta 1-->4GlcNAc beta 1-->4GlcNAcOT were found to have high affinity for VVLM-Sepharose. The antisera of VVLM did not produce precipitin line with VVLG in agar double diffusion plate indicating no serological relationship between VVLM and VVLG. However VVLM showed similar immunodeterminants of some other lectins of mannose specificity such as Con A, PSL, LCA and VFL.
Amino Acids↗
[Analysis of the target epitopes recognized by two monoclonal antibodies directed to egg-associated fractions of Schistosoma japonicum].
Two IgM isotype monoclonal antibodies (McAb), 2H10 and 2H1, recognizing repetitive epitopes on Schistosoma egg-associated molecules were characterized and their specificities were identified in a two-site sandwich ELISA system. In consistent with the differences in immunological behaviour and specificity demonstrated with immunoelectrophoresis (IEP) and immunofluorescent antibody (IFA) techniques, absolutely negative reactions found in the heterologous detecting system with alternated capture and detecting McAbs of the two revealed a complete incompatibility giving evidences that epitopes on different molecules were recognized. Immunological liability of the target antigen SEA or SEA-TCA to the two McAbs were demonstrated on sodium periodate and trifluoroacetic acid treatment indicating the biochemical nature of these epitopes were glycosyolated molecules with apparently higher resistance to the oxidizing agent showing in 2H10 recognizing epitopes. By means of an ion-gradient Mono-Q FPLC system (Pharmacia), 2H10-reactive epitopes of SEA, being tested not so efficiently adsorbed by ConA-sepharose affinity column, was found successfully concentrated in the profile eluted with pH 8.0 PBS at 0.2-0.4 NaCl ionic strength. Repeated trials on SDS-PAGE and Western blotting analysis with the reactive fractions further showed a heterogeneity of molecular weight range as well as the non-transferable property of the CHO-reactive groups.
Animals↗
Platelet activation by platelet aggregation factor from Eisenia foelide.
A platelet activating factor from earthworm, Eisenia foelide (EPAF, 25.9 mumol.L-1), induced human platelet aggregation and 5-HT (maximal release of 89% at EPAF 74.1 mumol.L-1) was detected during this process. Neither creatine phosphate/creatine phosphate kinase (CP/CPK) nor aspirin completely inhibited the EPAF-induced platelet aggregation. In the presence of fibrinogen, EPAF (55.6 mumol.L-1) induced the aggregation of human platelet which had been thrombin-treated and degranulated. Results indicated that EPAF was a potent platelet agonist and the EPAF-induced platelet aggregation was ADP- and TXA2-independent.
Animals↗
[Diabetes mellitus and its complications: prevention and treatment].
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Diabetes Complications↗
Amino acid sequencing of a trypsin inhibitor by refined 1.6 A X-ray crystal structure of its complex with porcine beta-trypsin.
The stoichiometric complex formed between porcine beta-trypsin and the Momordica charantia, Linn. Cucurbitaceae trypsin inhibitor-A (MCTI-A) was crystallized and its X-ray crystal structure determined using molecular replacement method. The primary sequence and topology of the inhibitor was determined by recognizing the electron density and refined to a final R value of 0.167 (7.0-1.6 A) with RMS deviation of bond lengths from standard values 0.012 A. The sequence was compared with those obtained by other groups and was found to be similar to the squash proteinase inhibitor. Its spatial structure and the conformation of its primary binding segment from Cys-3I (P3) to Glu-7I (P3') which contains the reactive scissile bond Arg-5I C-Ile-6I N were also very similar with other squash family proteinase inhibitors.
Amino Acid Sequence↗
[The role of arterial collagen nonenzymatic glycosylation (NEG) in the pathogenesis of diabetic macroangiopathy].
In this study, we found that 5-Hydroxymethylfurfural (5-HMF) released from aortic collagen was significantly increased in diabetic rats with diabetic duration of 4, 8, 12 weeks (P less than 0.001, P less than 0.001, P less than 0.001). Collagen-link fluorescence (CLF) was also increased in diabetic rats P less than 0.005, P less than 0.05, P less than 0.01 respectively). Mean collagen-content was higher in diabetic rats than in the controls (P greater than 0.05, P less than 0.01, P less than 0.01 respectively). In diabetic rats, the amount of 5-HMF was related to plasma glucose concentration (r = +0.52, P less than 0.01) and CLF (r = +0.58, P less than 0.01). There was a positive correlation between CLF and collagen-content in diabetic rats (r = +0.45, P less than 0.05). These results suggest that NEG do occur in arterial collagen. Advanced glycosylation end products could participate in glucose derived cross-link formation and accumulate through the lifetime of collagen, which may change the function and structure of collagen. The increase of collagen content of arterial wall in diabetic rats may probably have resulted from excessive formation of cross-links.
Animals↗
An Ehrlich chromogen in collagen cross-links.
A well-characterized three-chain peptide [(Col1)2 X T9] from human type III collagen was a rich source of Ehrlich chromogen. The corresponding two-chain peptide [(Col1)2] was not, implying that the Ehrlich chromogen is a trifunctional cross-link. (Col1)2 X T9 also contained pyridinoline, which is not an Ehrlich chromogen. The 7S domain of type IV collagen also contained an Ehrlich chromogen.
Amino Acids↗
Biocompatibility of poly (DL-lactide-co-glycolide) microspheres implanted into the brain.
The delivery of therapeutic molecules to the brain has been limited in part due to the presence of the blood-brain barrier. One potential solution is the implantation of biodegradable polymers with sustained release of drugs. Poly (DL-lactide-co-glycolide) (PLG) is a bioerodible polymer with a long and successful history of use as a suture material. More recently, PLG has been investigated for localized and sustained delivery of molecules into both peripheral sites and the brain. Despite its well-defined safety profile for parenteral applications, little information exists concerning the safety of PLG when implanted into the brain. To further characterize the biocompatibility of PLG in the brain, we examined the gliotic response following implants of PLG into the brains of rats. As a control, each animal received an injection of the suspension medium into the contralateral hemisphere. Following implantation, PLG was well tolerated. GFAP-positive astrocytes were observed throughout the cerebral cortex and striatum on both the implanted and control sides, with the reaction being greatest within the heavily myelinated fiber tracts of the corpus callosum. Quantitative analyses revealed that this reaction occurred within 1 h postsurgery, reached its peak at 1 week following surgery, and then decreased markedly by 1 month postsurgery. A minimal gliotic reaction was still present 1 year postsurgery but was localized to the needle tract. No differences in GFAP reactivity were seen between the polymer-implanted and control sides at any time point. Histological analysis determined that the majority of the PLG disappeared between 1 and 4 weeks. A set of parallel studies in which PLG samples were retrieved from the brain at various time points corroborated these findings and determined that the majority of PLG degraded within 2 weeks following implantation. Together, these results demonstrate that PLG is well tolerated following implantation into the CNS and that the astrocytic response to PLG is largely a consequence of the mechanical trauma that occurs during surgery. The biocompatibility of PLG implanted into the CNS provides further support for its use in a wide range of new therapeutic applications for sustained and localized drug delivery to the brain.
Animals↗