Biomedical subjects

Guofeng Huang

Publications and source records attributed to Guofeng Huang.

5 recordsLinked to original sources

PubMed2005

RGD-modified liposomes targeted to activated platelets as a potential vascular drug delivery system.

Local drug delivery has become an important treatment modality for the prevention of thrombotic events following coronary angioplasty. In this study, we investigate the ability of liposomes bearing surface conjugated linear Arg-Gly-Asp (RGD) peptide (GSSSGRGDSPA) moieties to target and bind activated platelets, and the effect of such RGD-modified liposomes on platelet activation and aggregation. The binding of RGD-liposomes to human platelets was assessed by fluorescence microscopy, phase contrast microscopy and flow cytometry. The effect of RGD-modified liposomes on platelet activation and aggregation was investigated in vitro, with and without platelet agonists. RGD-liposomes were found to bind activated platelets at levels significantly greater than the control RGE-liposomes. The RGD-liposomes did not exhibit any statistically significant effect on platelet activation or aggregation. The results demonstrate the ability of the RGD-modified liposomes to target and bind activated platelets without causing significant platelet aggregation and suggests a feasible way for the development of a platelet-targeted anti-thrombogenic drug delivery system. Furthermore, the approach can be extended to the development of liposomes for other vascular targets, for application in drug delivery or gene therapy.

Blood Platelets↗

PubMed2004

Nanoparticles of biodegradable polymers for clinical administration of paclitaxel.

Paclitaxel is one of the best antineoplastic drugs found from nature in the past decades, which has been found effective against a wide spectrum of cancers including ovarian cancer, breast cancer, small and non small cell lung cancer, colon cancer, head and neck cancer, multiple myeloma, melanoma, and Kaposi's sarcoma. Like many other anticancer drugs, it has difficulties in clinical administration due to its poor solubility in water and most pharmaceutical reagents. In its current clinical application, an adjuvant called Cremophor EL has to be employed, which has been found to be responsible for many serious side effects. Nanoparticles of biodegradable polymers can provide an ideal solution to such an adjuvant problem and realize a controlled and targeted delivery of the drug with better efficacy and less side effects. With further development, such as particle size optimization and surface coating, nanoparticle formulation of paclitaxel can promote a new concept of chemotherapy to realize its full efficacy and to improve quality of life of the patients, which includes personalized chemotherapy, local chemotherapy, sustained chemotherapy, oral chemotherapy, chemotherapy across the blood-brain barrier, chemotherapy across the microcirculation barrier, etc. The present research proposes a novel formulation for fabrication of nanoparticles of poly(lactic-co-glycolic acid) (PLGA) by a modified solvent extraction/evaporation technique, in which natural emulsifiers, such as phospholipids, cholesterol and vitamin E TPGS are creatively applied to achieve high drug encapsulation efficiency, desired drug released kinetics, high cell uptake and high cytotoxicity. The nanoparticles composed of various recipes and manufactured under various conditions were characterized by laser light scattering (LLS) for size and size distribution, scanning electron microscopy (SEM) and atomic force microscopy (AFM) for morphological properties, X-ray photoelectron spectroscopy (XPS) and Fourier Transformation Infrared Spectroscopy (FTIR) for surface chemistry, zeta-potential for surface charge, and differential scanning calorimetry (DSC) for the thermogram properties. The drug encapsulation efficiency and the drug release kinetics under in vitro conditions were measured by high performance liquid chromatography (HPLC). It was found that these natural emulsifiers have great advantages for nanoparticle formulation of paclitaxel over the traditional macromolecular emulsifiers, such as polyvinyl alcohol (PVA). Nanoparticles of desired small size and narrow size distribution can be obtained. The drug encapsulation efficiency can be achieved as high as 100 %. The released kinetics can be made under control. The HT-29 cancer cell line experiment showed that after 24 hours of incubation, the cell mortality caused by the drug administered by such nanoparticle formulation could be more than 13 times higher than that caused by the free drug under similar conditions.

Antineoplastic Agents, Phytogenic↗

PubMed2003

Prostate targeting ligands based on N-acetylated alpha-linked acidic dipeptidase.

To identify inhibitors of the intrinsic N-acetylated alpha-linked acidic dipeptidase (NAALADase) activity of prostate specific membrane antigen (PSMA) that may be useful for targeting imaging agents or chemotherapeutic drugs to disseminated prostate cancer, analogs of the tetrahedral transition state for hydrolysis of the natural substrate, N-acetylaspartylglutamate (NAAG), were synthesized. These compounds were assayed for their ability to inhibit the membrane-associated enzyme isolated from LNCaP prostate cancer cells. Active inhibitors were further assayed for their cytotoxicity and membrane binding. We have identified nine compounds, including fluorescent and iodine-labeled conjugates, which inhibit NAALADase enzyme activity with IC(50)s at, or below, 120nM. The binding of these compounds to the cell surface of viable LNCaP prostate tumor cells appears to be specific and saturable, and none of the compounds alter the cell cycle kinetics or induce apoptosis in LNCaP cells, suggesting that they are relatively innocuous and are suitable for targeting imaging agents or cytotoxic drugs to disseminated prostate cancer.

Antigens, Neoplasm↗

PubMed2003

[Physicochemical changes and maturity evaluation of solid organic waste compost].

Composting is one of the most effective ways for recycling of organic solid waste. Various characteristics of different kinds of organic solid waste cause various physicochemical changes during composting, as well as the different composting conditions. Stability and maturity evaluation are the measurement for compost quality and the safe guarantee for its agricultural utilization. Stability evaluation of compost focuses on the impacts to environment after its agricultural utilization, while maturity evaluation pays attention on the phytotoxicity to plant. Stability and maturity of compost are affected by several factors, such as the characteristics of raw materials, the composting condition, and so on. Stability could be assessed by compost temperature, color, evolution rate of CO2, consumption rate of O2, content of NO3(-)-N and quantities of pathogen, etc. Temperature was suggested to be one of the most convenient parameters for stability evaluation. Maturity could be assessed by various parameters, including the chemical, biological, and phytotoxical parameters. Seed germination index, as the phytotoxical parameter, was recommended to be one of the most convenient and reliable parameters of maturity evaluation.

Conservation of Natural Resources↗

PubMed2002

[On nitrogen transformations and maturity during composting of pig manure].

The contents of T-N, the ratios of soluble NO3-N/soluble T-N and soluble organic-N/soluble T-N increased after co-composting for 63 days of pig manure and sawdust with or without additional leaves, while the ratios of soluble NH4-N/soluble T-N decreased. In this study, addition of leaves was beneficial for maturation of pig manure composting, and it could shorten the composting time from 42 d to 35 d. The ratios of soluble NH4-N/soluble T-N, soluble NO3-N/soluble T-N and soluble organic N/soluble T-N correlated with seed germination index (GI) significantly, and it could be used for maturity evaluation.

Animals↗