Biomedical subjects

Liang Zhang

Publications and source records attributed to Liang Zhang.

97 records · Page 6Linked to original sources

PubMed2002

[A pilot study of bone marrow stromal cells intraocular transplantation in the S334 transgenic rats and Sprague-Dawley rats].

PURPOSE: To investigate the survival and differentiation of human bone marrow stromal cells (BMSC) intraocular transplantation in newborn S334 retinal degeneration transgenic rats and (Sprague-Dawley)SD rats. METHODS: Human bone marrow stromal cells line was grown on the adhesive substrate in the condition media including a-Modified Eagle medium (a-MEM)/10% fetal bovine serum. The experiments were divided into four groups: Group 1: BMSC + (Retinoid Acid) RA transplanted in S334 transgenic rats (n = 5); Group 2: BMSC transplanted in S334 transgenic rats (n = 5); Group 3: BMSC + RA transplanted in SD rats (n = 5); Group 4: BMSC transplanted in SD rats (n = 5). 2 microl cell suspension (about 4 x 10(4) cells) was injected into the vitreous space in the transgenic rats and normal SD rats at Postnatal 1 (P1) respectively. The right eyes were treated eyes and the left eyes were used as control. At P14 and P23, the rats were killed and enucleated for histological assays using plastic section. RESULTS: In Group 1, the transplanted cells were well survived. They could continue to differentiate and participate in late-stage retinal development. The number of inner nuclear layer increased. Moreover, the host retina increased their thickness, but photoreceptor cells were not rescued from transplant. In Group 2, at P14, the BMSC continue to differentiate toward their linage cell fate and formed into hemorrhage island structures with few neurons if RA was not applied. Group 3, BMSC could survive, migrate. The number of inner nuclear layer increased also. In Group 4, it revealed that host retina structures were disorganized and transplant cells formed atypical proliferating mass. CONCLUSIONS: This pilot experiment indicated that bone marrow stromal cells could survival, differentiate and participate in the retinal development after transplanted into vitreous space in the new born transgenic rats and SD rats. Histological assays showed that transplanted cells integrated with inner nuclear layer of host retina. Thus, bone marrow stromal cells may be a useful vehicle for auto- transplantation for the therapy of variety of retinal degenerative disorders.

Animals↗

PubMed2001

Sonochemical Processes and Formation of Gold Nanoparticles within Pores of Mesoporous Silica.

Mesoporous silica with gold nanoparticles inside its pores was prepared by the soaking and ultrasound-induced reduction method. This new composite was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and high-resolution transmission electron microscopy (HRTEM) techniques. The results showed that nearly spherical-shaped gold nanoparticles, with mean size in diameter of 5.2 nm, are located in the pores, most of which are less than 6 nm in diameter. The ultrasonic irradiation time dependence of optical absorption for the soaked porous solid sample, as suggested by the variation in absorbance at 310 and 544 nm, indicated the reduction of Au (III) ions, and the nucleation and aggregation of gold nanoparticles within pores of mesoporous silica. Additionally, the reaction rates estimated phenomenologically by the absorbance decay at 310 nm for both the porous sample and the corresponding soaking solution presented the enhancement of the sonochemical reduction rate of Au (III) ions within pores of mesoporous silica. It is assumed that the extensive liquid-solid interfacial zones in the pores, due to the high specific surface areas and great porosity of the mesoporous solid, are the major regions where the efficient sonochemical reduction induced by the cavitation takes place. Copyright 2001 Academic Press.

Journal Article↗

PubMedDate not supplied

"Meshed-Bag Gathered-Bunch" method for solid-phase synthesis of small molecular diverse compounds.

A new "Meshed-Bag Gathered-Bunch" technology for the solid-phase synthesis of chemical libraries was developed. Using such technology, we synthesized muramyl dipeptide mimetics including derivatives at the N- and C-terminus, cyclic muramyl dipeptide mimetics, muramyl dipeptide and Tuftsin's analogue conjugates. The advantages of such a method include ease of manufacture, low unit cost of production, the physical encoding method, and the compatibility with both parallel and "split-mix" approaches.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMedDate not supplied

Parallel approach for solution-phase synthesis of 2-quinoxalinol analogues and their inhibition of LPS-induced TNF-alpha release on mouse macrophages in vitro.

A parallel solution-phase synthesis of 2-quinoxalinol analogues is described. The key step-simultaneous reductions of m-Ar(NO2)2 to m-Ar(NH2)2 was investigated extensively. We obtained preliminary pharmacological activity of those analogues for the inhibition of LPS-induced TNF-alpha release on mouse macrophage in vitro. Two compounds revealed inhibitory activity, with IC50 values of 0.40 microM (7-amino-6-[(3-methoxypropyl)amino]-3-methyl-2-quinoxalinol) and 2.2 microM (7-amino-6-[(3-butoxypropyl)amino]-3-methyl-2-quinoxalinol), respectively.

Animals↗

PubMedDate not supplied

Solution-phase parallel synthesis of a 1,2,7-trialkyl-1H-imidazo[4,5-g]quinoxalin-6-ol library scaffold.

This paper describes solution-phase parallel synthesis of a library with a novel 1,2,7-trialky-1H-imidazo[4,5-g]quinoxalin-6-ol scaffold and three points of diversity. The library is prepared using 1,5-difluoro-2,4-dinitrobenzene as the starting material and commercially available chemicals as the building blocks. A new, inexpensive, and practical apparatus for parallel filtration is also described.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Screening and identification of linear B-cell epitopes and entry-blocking peptide of severe acute respiratory syndrome (SARS)-associated coronavirus using synthetic overlapping peptide library.

A 10-mer overlapping peptide library has been synthesized for screening and identification of linear B-cell epitopes of severe acute respiratory syndrome associated coronavirus (SARS-CoV), which spanned the major structural proteins of SARS-CoV. One hundred and eleven candidate peptides were positive according to the result of PEPscan, which were assembled into 22 longer peptides. Five of these peptides showed high cross-immunoreactivities (approximately 66.7 to 90.5%) to SARS convalescent patients' sera from the severest epidemic regions of the China mainland. Most interestingly, S(471-503), a peptide located at the receptor binding domain (RBD) of SARS-CoV, could specifically block the binding between the RBD and angiotensin-converting enzyme 2, resulting in the inhibition of SARS-CoV entrance into host cells in vitro. The study demonstrated that S(471-503) peptide was a potential immunoantigen for the development of peptide-based vaccine or a candidate for further drug evaluation against the SARS-CoV virus-cell fusion.

Amino Acid Sequence↗

PubMedDate not supplied

Benzofused tricycles based on 2-quinoxalinol.

This paper describes our recent efforts to synthesize novel compound scaffolds integrating 2-quinoxalinol with privileged structures of 1,3-dihydro-benzoimidazol-2-one, 1,3-dihydro-benzoimidazole-2-thione, 3-hydroxy-1H-quinoxalin-2-one, 2H-benzo[1,4]oxazin-3-ol, 2H-benzo[1,4]thiazin-3-ol, and 1,3,4,5-tetrahydro-benzo[1,4]diazepin-2-one, respectively. Eight novel benzofused tricycles and their substituent diversity points were developed. These include pyrazino[2,3-g]quinoxaline-2,8-diol (I), 3-hydroxy-6,8,9,10-tetrahydro-1,4,6,10-tetraaza-cyclohepta[b]naphthalen-7-one (II), 6-hydroxy-4H-1-oxa-4,5,8-triaza-anthracen-3-one (III), 6-hydroxy-4H-1-thia-4,5,8-triaza-anthracen-3-one (IV), 6-hydroxy-1,1-dioxo-1,4-dihydro-2H-1lambda(6)-thia-4,5,8-triaza-anthracen-3-one (V), 6-hydroxy-1,3-dihydro-imidazo[4,5-g]quinoxalin-2-one (VI), 6-hydroxy-1,3-dihydro-imidazo[4,5-g]quinoxaline-2-thione (VII), and 7-hydroxy-1,4-dihydro-pyrazino[2,3-g]quinoxaline-2,3-dione (VIII). This strategy of integrating two benzofused privileged structures into one molecule may provide a greater chance for the discovery of novel lead compounds.

Anthracenes↗