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Hong M, Wang G, Yang R. [Study on improvement of liver cirrhosis and liver function in hepatolenticular degeneration patients treated with integrated Traditional and Western medicine]. ZHONGGUO ZHONG XI YI JIE HE ZA ZHI ZHONGGUO ZHONGXIYI JIEHE ZAZHI = CHINESE JOURNAL OF INTEGRATED TRADITIONAL AND WESTERN MEDICINE 2000; 20:890-2. [PMID: 11938856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To observe the effects of sodium dimercaptosulphonate (DMPS) plus Gandou tablet, DMPS and calcium disodium ethylene diaminotetraacetate (EDTA) on improving liver cirrhosis and liver function of hepatolenticular degeneration (HLD) patients. METHODS One hundred and forty-six HLD patients were divided into A, B, C three groups, and treated with DMPS plus Gandou tablet, DMPS and EDTA respectively, the therapeutic course was 8 weeks for three groups. The ultrasonography of liver, electrophoresis of serum protein and excretion of urinary copper were observed. RESULTS The ultrasonography of liver was improved in all groups, the rate of improvement of group A was 54.0%, B was 44.0% and C was 39.1%. The amounts of serum albumin in A and B groups increased (P < 0.01, P < 0.05), and gamma-globulin decreased in all groups (P < 0.05). The excretion of urinary copper increased obviously in all groups (P < 0.01), and A, B groups increased more than that of C group (P < 0.05). CONCLUSIONS The de-copper therapy could improve liver cirrhosis and liver function. The effect of DMPS plus Gandou tablet was better than that of DMPS and EDTA.
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Brown BL, Franklin DE, Gaffney PM, Hong M, Dendanto D, Kornfield I. Characterization of microsatellite loci in the eastern oyster, Crassostrea virginica. Mol Ecol 2000; 9:2217-9. [PMID: 11221805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Abstract
Although there are general assumptions that physiological and behavioral indices of emotion are interrelated, empirical research has revealed inconsistent findings with regard to their degree of association, particularly in children. Two studies were conducted to examine the relations between cardiovascular reactivity and emotional behavior. In the first study, 3- to 6-year-olds completed challenging tasks during which measures of their physiological responses and facial expressions were obtained. With age, children's heart rate decreased, vagal tone increased, and facial expressions became slightly more exaggerated. However, children's physiologic reactions were unrelated to their concurrent facial expression when all children were considered, when only boys were considered, and when children extreme in their physiologic reactions were considered. Only among girls was physiologic reactivity moderately associated with concurrent negative expressiveness. In the second study, 4- and 5-year-olds' physiologic reactivity was examined as a predictor of later overt emotional reaction to venipuncture episodes. Children's overt emotional reactions were consistent across repeated venipunctures, and girls were more visibly distressed than boys. As in the first study, physiologic reactivity was generally unrelated to children's behavioral responses. Findings have implications for assumptions about the degree of coupling between biological and behavioral emotional systems in childhood.
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Baker KA, Sadi D, Hong M, Mendez I. Simultaneous intrastriatal and intranigral dopaminergic grafts in the parkinsonian rat model: role of the intranigral graft. J Comp Neurol 2000; 426:106-16. [PMID: 10980486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The current transplantation strategy in experimental and clinical Parkinson's disease (PD) has been to place nigral dopaminergic grafts not in their ontogenic site (substantia nigra) but in their target area (striatum). Although intrastriatal dopaminergic grafts are capable of reinnervating the striatum, they fail to reinnervate the nigra, which may be an important factor limiting the efficacy of fetal tissue transplantation in parkinsonian patients. We have previously shown that simultaneous intrastriatal and intranigral dopaminergic grafts (double grafts) may provide a more complete restoration of the nigrostriatal circuitry (Mendez et al. [1996] J Neurosci 16:7216-7227; Mendez and Hong [1997] Brain Res 778:194-205). In the present study, we investigated the contribution of the intranigral graft to functional recovery in double-grafted hemiparkinsonian rats. Twenty Wistar rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal pathway were divided into two groups and received either double grafts (n = 10) or intrastriatal grafts alone (n = 10). Following transplantation, both intrastriatally and double-grafted animals had a significant decrease in rotational behavior. However, only animals with double grafts exhibited a significant increase in contralateral adjusting step performance. The intranigral graft was subsequently lesioned by a second 6-OHDA injection. Following the second lesion, animals with double grafts exhibited a significant reversal of rotational behavior and a 51% reduction in contralateral adjusting step performance. The reversal in functional recovery correlated with a significant loss of intranigral grafted neurons. These results suggest that the intranigral graft has an important role in the functional recovery of double-grafted animals. Restoration of dopaminergic innervation to both the nigra and the striatum may be crucial for optimizing graft efficacy and may be a superior strategy in neural transplantation for PD.
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Liang Y, Cao R, Su W, Hong M, Zhang W. Syntheses, Structures, and Magnetic Properties of Two Gadolinium(III)-Copper(II) Coordination Polymers by a Hydrothermal Reaction This work is supported by the NNSF of China, the NSF of Fujian Province, and the Key Project from the CAS. Angew Chem Int Ed Engl 2000; 39:3304-3307. [PMID: 11028085 DOI: 10.1002/1521-3773(20000915)39:18<3304::aid-anie3304>3.0.co;2-h] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wiedmer SK, Cassely A, Hong M, Novotny MV, Riekkola ML. Electrophoretic studies of polygalacturonate oligomers and their interactions with metal ions. Electrophoresis 2000; 21:3212-9. [PMID: 11001220 DOI: 10.1002/1522-2683(20000901)21:15<3212::aid-elps3212>3.0.co;2-n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Polygalacturonic acid, a linear homopolysaccharide, was investigated by capillary electrophoresis (CE) using linear polyacrylamide-coated capillaries and laser-induced fluorescence (LIF) detection. A successful separation of its fluorescently labeled oligomers was achieved through sieving in polyacrylamide entangled matrices. The reaction conditions for the derivatization of polygalacturonic acid were optimized. In studying the interactions between polygalacturonic acid and various metal ions, the end-label, free-solution electrophoretic (ELFSE) technique, developed earlier in our laboratory (Sudor, J., Novotny, M. V., Anal. Chem. 1995, 67, 4205-4209) was found preferable to the sieving method. ELFSE is fast and convenient in that no polymer solutions are needed for the separation. The investigation showed that for the moderately large oligomers, the strongest binding occurred with calcium and cadmium ions, while the smallest interaction was observed with magnesium ions.
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Quehenberger P, Bierhaus A, Fasching P, Muellner C, Klevesath M, Hong M, Stier G, Sattler M, Schleicher E, Speiser W, Nawroth PP. Endothelin 1 transcription is controlled by nuclear factor-kappaB in AGE-stimulated cultured endothelial cells. Diabetes 2000; 49:1561-70. [PMID: 10969841 DOI: 10.2337/diabetes.49.9.1561] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Incubation of bovine aortic endothelial cells (BAECs) with erythrocytes from patients with type 2 diabetes induced an increase in endothelin 1 (ET-1) production. The effect of erythrocytes on ET-1 synthesis was dependent on glycemic control. ET-1 levels after incubation with erythrocytes derived from patients with HbA(1c) levels <6% were just half the levels observed after incubation with erythrocytes from patients with HbA(1c) levels >8%. Nepsilon-(carboxymethyl)lysine (CML)-containing protein isolated from patients' erythrocytes induced ET-1, and CML-containing protein-dependent ET-1 induction was blocked by the recombinant decoy peptide soluble receptor for advanced glycation end products (AGEs), which comprises the NH2-terminal Ig domain of the receptor for AGEs. In vitro-generated AGEs induced ET-1 mRNA transcription (nuclear run-on assay and Northern blot) in a time- and dose-dependent manner. Transient transfection of BAECs with a chimeric construct containing the 5' promoter region of the ET-1 gene linked to a reporter gene confirmed that AGE induced ET-1 promoter activity. Electrophoretic mobility shift assay confirmed AGE-inducible binding of members of the nuclear factor-kappab (NF-kappaB) family to a potential binding site at -2,090 bp. Binding was functionally significant because overexpression of the cytoplasmic inhibitor of NF-kappaB or deletion of the NF-kappaB binding site reduced ET-1 induction, whereas overexpression of NF-kappaB p65 induced ET-1 even in the absence of AGEs. Thus, ET-1 transcription is controlled by the AGE-inducible redox-sensitive transcription factor NF-kappaB.
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Hong M, Zhao Y, Su W, Cao R, Fujita M, Zhou Z, Chan AS. A Silver(I) Coordination Polymer Chain Containing Nanosized Tubes with Anionic and Solvent Molecule Guests This work was supported by the National Nature Science Foundation of China. M.C.H. thanks the Croucher Foundation of Hong Kong for financial support. Angew Chem Int Ed Engl 2000; 39:2468-2470. [PMID: 10941104 DOI: 10.1002/1521-3773(20000717)39:14<2468::aid-anie2468>3.0.co;2-i] [Citation(s) in RCA: 266] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kim KP, Han SK, Hong M, Cho W. The molecular basis of phosphatidylcholine preference of human group-V phospholipase A2. Biochem J 2000; 348 Pt 3:643-7. [PMID: 10839997 PMCID: PMC1221108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Human group-V phospholipase A(2) (hVPLA(2)) is a secretory phospholipase A(2) (PLA(2)) that is involved in eicosanoid formation in such inflammatory cells as macrophages and mast cells. We showed that hVPLA(2) can bind phosphatidylcholine membranes and hydrolyse phosphatidylcholine molecules much more efficiently than human group-IIa PLA(2), which accounts for its high activity on the outer plasma membrane of mammalian cells. To understand the molecular basis of the high phosphatidylcholine specificity of hVPLA(2), we mutated several residues (Gly-53, Glu-56 and Glu-57) that might be involved in interaction with an active-site-bound phospholipid molecule. Phospholipid head-group specificities of mutants determined using polymerized mixed-liposome substrates indicate that a small glycine residue in position 53 is important for accommodating a bulky choline head group. Also, results indicated that two anionic residues, Glu-56 and Glu-57, favourably interact with cationic head groups of phosphatidylcholine and phosphatidylethanolamine. Together, these steric and electrostatic properties of the active site of hVPLA(2) allow for effective binding and hydrolysis of a bulky cationic choline head group of phosphatidylcholine, which is unique among mammalian secretory PLA(2)s.
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Sun D, Cao R, Liang Y, Hong M, Su W, Weng J. μ-Terephthalato-bis[bis(1,10-phenanthroline)copper(I)] diperchlorate. Acta Crystallogr C 2000; 56:E240-1. [PMID: 15263109 DOI: 10.1107/s0108270100006119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2000] [Accepted: 04/20/2000] [Indexed: 11/10/2022] Open
Abstract
The title compound, [Cu(2)(C(8)H(4)O(4))(C(12)H(8)N(2))(4)](ClO(4))(2), was prepared from the hydrothermal reaction of CuCl(2), 1,4-dicyanobenzene, 1,10-phenanthroline and water at 443 K. The compound is a dimer in which the cation lies about an inversion center. The terephthalate moiety acts as a bridging ligand and the phenanthrolines as terminal ligands. The unique Cu atom is coordinated by two O and four N atoms in a distorted octahedral geometry, with Cu-O distances of 1.955 (2) and 2.815 (2) A, and Cu-N distances of 2.008 (2) to 2.216 (2) A.
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Bao M, Hong M, Su W, Cao R. Bis(N,N-diethyl-1,1-diselenocarbamato-Se)selenium, [(Se2CNEt2)2Se]. Acta Crystallogr C 2000; 56:E219-20. [PMID: 15263160 DOI: 10.1107/s0108270100005497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2000] [Accepted: 04/10/2000] [Indexed: 11/10/2022] Open
Abstract
The polyseleno title compound, bis(N,N-diethylselenocarbamoyl) triselenide, [(Se(2)CNEt(2))(2)Se] or C(10)H(20)N(2)Se(5), is obtained from the disproportion of sodium N,N-diethyl-1,1-diselenocarbamate. An Se atom connects two N,N-diethyl-1,1-diselenocarbamate groups with Se-Se distances in the range 2.4500 (11)-2.8601 (12) A
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Abstract
Capillary electrophoresis (CE) has been applied to the study of complexation between dextrins and polyiodides. A baseline separation of fluorescently labeled dextrin oligomers has provided a unique platform for the observation of a contribution of single oligomers to the complexation process that could previously be measured only in bulk. The complex formation was easily recognized through comparison of peak migration times and peak shapes in the presence and absence of polyiodides. The degree of polymerization (DP) number was found crucial in the binding process, but the I2/I- ratio in a solution also appeared to determine the nature of complexation. The effects of buffer pH and ionic strength upon complexation were also briefly investigated. Diodearray spectra in the visible wavelength range confirmed the differential complexation of unlabeled maltodextrins with different DP values after a CE iodine affinity separation. 13C-nuclear magnetic resonance (NMR) spectral data on differently sized dextrin fractions were found to be in good agreement with the results from CE measurements.
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Mendez I, Dagher A, Hong M, Hebb A, Gaudet P, Law A, Weerasinghe S, King D, Desrosiers J, Darvesh S, Acorn T, Robertson H. Enhancement of survival of stored dopaminergic cells and promotion of graft survival by exposure of human fetal nigral tissue to glial cell line--derived neurotrophic factor in patients with Parkinson's disease. Report of two cases and technical considerations. J Neurosurg 2000; 92:863-9. [PMID: 10794303 DOI: 10.3171/jns.2000.92.5.0863] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The authors have studied the ability of glial cell line-derived neurotrophic factor (GDNF) to promote survival of human fetal dopaminergic tissue after a storage period of 6 days and subsequent implantation into the human putamen. The results indicate that GDNF promotes survival of stored dopaminergic cells. Cells stored without GDNF had a 30.1% decrease in survival time compared with those exposed to GDNF. Two patients with Parkinson's disease received bilateral putaminal implants of fetal dopaminergic cells exposed to GDNF for 6 days and showed enhancement of graft survival as assessed by positron emission tomography scanning. A mean increase of 107% in putaminal fluorodopa uptake from baseline values was observed 12 months postgrafting.
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Probst A, Götz J, Wiederhold KH, Tolnay M, Mistl C, Jaton AL, Hong M, Ishihara T, Lee VM, Trojanowski JQ, Jakes R, Crowther RA, Spillantini MG, Bürki K, Goedert M. Axonopathy and amyotrophy in mice transgenic for human four-repeat tau protein. Acta Neuropathol 2000; 99:469-81. [PMID: 10805089 DOI: 10.1007/s004010051148] [Citation(s) in RCA: 289] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Coding region and intronic mutations in the tau gene cause frontotemporal dementia and parkinsonism linked to chromosome 17. Some of these mutations lead to an overproduction of tau isoforms with four microtubule-binding repeats. Here we have expressed the longest four-repeat human brain tau isoform in transgenic mice under the control of the murine Thy1 promoter. Transgenic mice aged 3 weeks to 25 months overexpressed human tau protein in nerve cells of brain and spinal cord. Numerous abnormal, tau-immunoreactive nerve cell bodies and dendrites were seen. In addition, large numbers of pathologically enlarged axons containing neurofilament- and tau-immunoreactive spheroids were present, especially in spinal cord. Signs of Wallerian degeneration and neurogenic muscle atrophy were observed. When motor function was tested, transgenic mice showed signs of muscle weakness. Taken together, these findings demonstrate that overexpression of human four-repeat tau leads to a central and peripheral axonopathy that results in nerve cell dysfunction and amyotrophy.
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Baker KA, Hong M, Sadi D, Mendez I. Intrastriatal and intranigral grafting of hNT neurons in the 6-OHDA rat model of Parkinson's disease. Exp Neurol 2000; 162:350-60. [PMID: 10739641 DOI: 10.1006/exnr.1999.7337] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The clinical findings on neural transplantation for Parkinson's disease (PD) reported thus far are promising but many issues must be addressed before neural transplantation can be considered a routine therapeutic option for PD. The future of neural transplantation for the treatment of neurological disorders may rest in the discovery of a suitable alternative cell type for fetal tissue. One such alternative may be neurons derived from a human teratocarcinoma (hNT). hNT neurons have been shown to survive and integrate within the host brain following transplantation and provide functional recovery in animal models of stroke and Huntington's disease. In this study, we describe the transplantation of hNT neurons in the substantia nigra (SN) and striatum of the rat model for PD. Twenty-seven rats were grafted with one of three hNT neuronal products; hNT neurons, hNT-DA neurons, or lithium chloride (LiCl) pretreated hNT-DA neurons. Robust hNT grafts could be seen with anti-neural cell adhesion molecule and anti-neuron-specific enolase immunostaining. Immunostaining for tyrosine hydroxylase (TH) expression revealed no TH-immunoreactive (THir) neurons in any animals with hNT neuronal grafts. THir cells were observed in 43% of animals with hNT-DA neuronal grafts and all animals with LiCl pretreated hNT-DA neuronal grafts (100%). The number of THir neurons in these animals was low and not sufficient to produce significant functional recovery. In summary, this study has demonstrated that hNT neurons survive transplantation and express TH in the striatum and SN. Although hNT neurons are promising as an alternative to fetal tissue and may have potential clinical applications in the future, further improvements in enhancing TH expression are needed.
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deAzevedo E, Kennedy S, Hong M. Determination of slow motions in extensively isotopically labeled proteins by magic-angle-spinning 13C-detected 15N exchange NMR. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00310-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Mendez I, Baker KA, Hong M. Simultaneous intrastriatal and intranigral grafting (double grafts) in the rat model of Parkinson's disease. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 32:328-39. [PMID: 10751681 DOI: 10.1016/s0165-0173(99)00091-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Experimental and clinical studies of neural transplantation in Parkinson's disease have focused on the placement of fetal dopaminergic grafts not in their ontogenic site (substantia nigra) but in the main nigral target area (striatum). The reason for this is the apparent inability of intranigral nigral grafts to extend axons for long distances reinnervating the ipsilateral striatum. This review presents previous work by our laboratory [I. Mendez, M. Hong, Reconstruction of the striato-nigro-striatal circuitry by simultaneous double dopaminergic grafts: a tracer study using fluorogold and horseradish peroxidase, Brain Res. 778 (1997) 194-205; I. Mendez, D. Sadi, M. Hong., Reconstruction of the nigrostriatal pathway by simultaneous intrastriatal and intranigral dopaminergic transplants, J. Neurosci. 16 (1996) 7216-7227] using a new transplantation strategy aimed at restoring dopaminergic innervation of the nigra and striatum by simultaneous dopaminergic transplants placed in the substantia nigra and ipsilateral striatum (double grafts) in the 6-hydroxydopamine lesioned adult rat brain. These double grafts achieve not only greater striatal reinnervation than the standard intrastriatal grafts but also produce a faster and more complete behavioural recovery six weeks after transplantation. Injection of the retrograde tracer fluorogold into the striatum and nigra resulted in fluorescent labeled cells within the intranigral graft and the intrastriatal graft and surrounding striatum, respectively suggesting that these double grafts promote at least partial reconstruction of the nigrostriatal dopaminergic pathway. This double graft strategy may have potential implications in clinical neural transplantation for Parkinson's disease.
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Harris DJ, Bonagamba TJ, Hong M, Schmidt-Rohr K. Conformation of Poly(ethylene oxide)−Hydroxybenzene Molecular Complexes Studied by Solid-State NMR. Macromolecules 2000. [DOI: 10.1021/ma992087i] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mendez I, Hong M, Smith S, Dagher A, Desrosiers J. Neural transplantation cannula and microinjector system: experimental and clinical experience. Technical note. J Neurosurg 2000; 92:493-9. [PMID: 10701543 DOI: 10.3171/jns.2000.92.3.0493] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The authors present a simple, reliable, and safe system for performing neural transplantation in the human brain. The device consists of a transplantation cannula and microinjector system that has been specifically designed to reduce implantation-related trauma and to maximize the number of graft deposits per injection. The system was evaluated first in an experimental rat model of Parkinson's disease (PD). Animals in which transplantation with this system had been performed showed excellent graft survival with minimal trauma to the brain. Following this experimental stage, the cannula and microinjector system were used in eight patients with PD enrolled in the Halifax Neural Transplantation Program who received bilateral putaminal transplants of fetal ventral mesencephalic tissue. A total of 16 transplantation operations and 64 trajectories were performed in the eight patients, and there were no intraoperative or perioperative complications. Magnetic resonance imaging studies obtained 24 hours after surgery revealed no evidence of tissue damage or hemorrhage. Transplant survival was confirmed by fluorodopa positron emission tomography scans obtained 6 and 12 months after surgery. As neural transplantation procedures for the treatment of neurological conditions evolve, the ability to deliver viable grafts safely will become critically important. The device presented here has proved to be of value in maximizing the number of graft deposits while minimizing implantation-related trauma to the host brain.
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Abstract
The new versatile multidentate nonchelating ligand 1,2-bis[(2-pyr-imidinyl)-sulfanylmethyl]benzene (bpsb) was designed and prepared for supramolecular syntheses. Self-assembly between silver nitrate and the bpsb ligand resulted in the polymer [Ag4(bpsb)2-(NO3)4]n (1) with a single-stranded helical chain structure. Each bpsb ligand in 1 acts as a tetradentate ligand, in which two sulfur atoms and two nitrogen atoms from different pyrimidine groups coordinate to four Ag atoms in four different directions. The nitrate anions serve as a template for the formation of the helix and are either embedded in the interior of the helix or located in the flank of the helix. Self-assembly between silver perchlorate and the bpsb ligand under the same conditions gave rise to the polymer [Ag2(bpsb)3(ClO4)2]n (2) comprising a two-dimensional lamellar network containing crownlike cavities. The silver atoms in two adjacent layers are arranged staggered in 2. The two-dimensional lamellar network comprising isolated cavities of [Ag6(bpsb)6] is very different from that of usual honeycomb structures.
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Hong M, Chen W, Li D, Lu S. [High level expression of foreign gene via multiple joined operons and a new concept on the restricted constant of total amount of plasmid DNA per cell of Escherichia coli]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 2000; 22:30-5. [PMID: 12903489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
OBJECTIVE To examine the feasibility of linking operons in tandem to enhance expression of heterologous genes in Escherichia coli and to clarify the potential control mechanism of the total plasmid DNA amount in each host cell. METHODS Two series of expression plasmids, CW11 and CW12, containing 1 to 4 and 1 to 3 heterologous gene operon(s), respectively, were constructed. The molecular size of the CW11 series varied from 5.47 kb to 12.26 kb in 2.25 kb increments. The CW12 series varied from 5.40 kb to 9.72 kb in 2.16 kb increments. Protein expression was analyzed via SDS-PAGE and laser scanning. Plasmid copy number was determined by incorporation with 3H-TdR([3H]-thymidine). RESULTS No influence of the tandem-joined operons on host growth and plasmid stability was observed. Upon induction, the desired protein accumulated in the CW11 series were 46.0%, 54.8%, 56.1%, and 60.1% of total cell protein. In the CW12 series, the yields were 33.5%, 44.0%, and 47.1% of total cell protein. With increasing size, however, plasmid copy number decreased. Further calculation showed that the total amount of plasmid DNA per cell is restricted to some extent. There seems exists a mechanism to control the maximum level of total plasmid DNA amount in each host cell. CONCLUSIONS Increasing the target gene dosage by tandem linking of operons enhanced the expression level of a desired protein. Although the size (kb) and the copy number of each plasmid are negatively interrelated, it seems that as for certain plasmids, their total DNA amount per cell is a restricted constant for a specific E. coli strain under identical incubation condition.
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Hong M, Schlichter L, Bendayan R. A Na(+)-dependent nucleoside transporter in microglia. J Pharmacol Exp Ther 2000; 292:366-74. [PMID: 10604972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
In the central nervous system, HIV-1 has a defined tropism for brain macrophages and microglia. Nucleoside analog drugs such as zidovudine improve the clinical and neuropsychological functions in HIV-demented patients. Multiple carrier-mediated transport systems can play an important role in the membrane permeation of nucleosides and nucleoside analog drugs in a number of cells. The purpose of this project was to characterize the uptake properties of the pyrimidine nucleoside probe thymidine by a continuous rat microglia cell line (MLS-9) grown as a monolayer on an impermeable substratum. Approximately 50% of thymidine (10 microM) uptake by the monolayer cells was found to be Na(+) dependent. Kinetics of specific thymidine uptake showed a single saturation system (K(m) = 44 microM at 37 degrees C) and a Na(+)/thymidine stoichiometry of 2:1. Pyrimidine and purine nucleoside probes (50 microM) exerted a competitive inhibitory effect on specific thymidine uptake with K(i) values of 40, 38, 45, and 39 microM for adenosine, uridine, guanosine, and cytidine, respectively. In addition, nucleoside analog drugs significantly decreased specific thymidine uptake, with IC(50) values of 135.1 microM for abacavir and 0.6 microM for zidovudine, which inhibited in a noncompetitive manner. These results suggest that a Na(+)-dependent nucleoside transport system is present in rat microglia and that long-range interactions between antiretroviral nucleoside analog drugs and the nucleoside substrates may occur at the transporter sites.
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Hong M, Song WJ, Li SY, Yuan ZY. [The influence on oxgen-carrying capacity of procine hemoglobin while attached PEG to increase its total molecular weight]. SHENG WU GONG CHENG XUE BAO = CHINESE JOURNAL OF BIOTECHNOLOGY 2000; 16:22-6. [PMID: 10883270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Increasing the total molecular weight of hemoglobin through PEG modification has been proved to be a better choice in prolonging vascular retention time. As a long, linear, hydrophilic molecular, PEG exerts significant influence on the oxygen-carrying properties of porcine hemoglobin (pHb) when attached. PEG-hemoglobins exhibit a wide range of differences in their properties depending on which molecular weight PEG is selected, how many PEGs are bound and whether the allosteric cofactors exist or not. Furthermore, DBBF intracross-linked pHbs are bound to various active PEG. As a result, with the combination of the three methods: DBBF intracross-linking, allosteric cofactors involving and PEG conjugating, a tetramer stable and high oxygen-carrying capacity pHb derivitive with large molecular weight is obtained.
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Bolliger B, Erbudak M, Hong M, Kwo J, Kortan AR, Mannaerts JP. Structure of epitaxial Gd2O3 films and their registry on GaAs(100) substrates. SURF INTERFACE ANAL 2000. [DOI: 10.1002/1096-9918(200008)30:1<514::aid-sia760>3.0.co;2-k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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