1.Modification by wheat germ agglutinin delays the ocular elimination of liposome.
Wen-Jian ZHANG ; Dong-Xiao YANG ; Ling-Lin FENG ; Fei WANG ; Gang WEI ; Wei-Yue LU
Acta Pharmaceutica Sinica 2014;49(4):543-549
The purpose of this study is to explore the feasibility of wheat germ agglutinin (WGA) modified liposome as a vehicle for ophthalmic administration. Liposome loaded with 5-carboxyfluorescein (FAM) was prepared by lipid film hydration method. WGA was thiolated and then conjugated to the surface of the liposome via polyethylene glycol linker to constitute the WGA-modified and FAM-loaded liposome (WGA-LS/FAM). The amount of thiol groups on each WGA molecule was determined, and the bioactivity of WGA was estimated after it was modified to the surface of liposome. The physical and chemical features of the WGA-modified liposome were characterized and the ocular bioadhesive performance was evaluated in rats. The result showed that each thiolated WGA molecule was conjugated with 1.32 thiol groups. WGA-LS/FAM had a mean size of (97.40 +/- 1.39) nm, with a polydispersity index of 0.23 +/- 0.01. The entrapment efficacy of FAM was about (2.95 +/- 0.21)%, and only 4% of FAM leaked out of the liposome in 24 h. Erythrocyte agglutination test indicated that after modification WGA preserved the binding activity to glycoprotein. The in vivo ocular elimination of WGA-LS/FAM fitted first-order kinetics, and the elimination rate was significantly slower than that of the unmodified liposome, demonstrating WGA-modified liposome is bioadhesive and suitable for ophthalmic administration.
Absorption, Physicochemical
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Adhesiveness
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Administration, Ophthalmic
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Animals
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Drug Carriers
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Eye
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metabolism
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Fluoresceins
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chemistry
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Liposomes
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administration & dosage
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chemistry
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pharmacokinetics
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Male
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Particle Size
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Polyethylene Glycols
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chemistry
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Rats
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Rats, Sprague-Dawley
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Wheat Germ Agglutinins
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administration & dosage
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chemistry
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pharmacokinetics
2.Development of Lead Free Shielding Material for Diagnostic Radiation Beams.
Tae Jin CHOI ; Young Kee OH ; Jin Hee KIM ; Ok Bae KIM
Korean Journal of Medical Physics 2010;21(2):232-237
The shielding materials designed for replacement of lead equivalent materials for lighter apron than that of lead in diagnostic photon beams. The absorption characteristics of elements were applied to investigate the lead free material for design the shielding materials through the 50 kVp to 110 kVp x-ray energy in interval of 20 kVp respectively. The idea focused to the effect of K-edge absorption of variable elements excluding the lead material for weight reduction. The designed shielding materials composited of Tin 34.1%, Antimon 33.8% and Iodine 26.8% and Polyisoprene 5.3% gram weight account for 84 percent of weight of lead equivalent of 0.5 mm thickness. The size of lead-free shielder was 200x200x1.5 mm3 and 3.2 g/cm3 of density which is equivalent to 0.42 mm of Pb. The lead equivalent of 0.5 mm thickness generally used for shielding apron of diagnostic X rays which is transmitted 0.1% for 50 kVp, 0.9% for 70 kVp and 3.2% for 90 kVp and 4.8% for 110 kVp in experimental measurements. The experiment of transmittance for lead-free shielder has showed 0.3% for 50 kVp, 0.6% for 70 kVp, 2.0% for 90 kVp and 4.2% for 110 kVp within 0.1%. respectively. Using the attenuation coefficient of experiments for 0.5 mm Pb equivalent of lead-free materials showed 0.1%. 0.3%, 1.0% and 2.4%, respectively. Furthermore, the transmittance of lead-free shielder for scatter rays has showed the 2.4% in operation energy of 50 kVp and 5.9% in energy of 110 kVp against 2.4% and 5.1% for standard lead thickness within 0.2% discrepancy, respectively. In this experiment shows the designed lead-free shielder is very effective for reduction the apron weight in diagnostic radiation fields.
Absorption
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Iodine
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Radiation Protection
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Tin
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Weight Loss
3.Study on the prediction of visible absorption maxima of azobenzene compounds.
Jun-na LIU ; Zhi-rong CHEN ; Shen-feng YUAN
Journal of Zhejiang University. Science. B 2005;6(6):584-589
The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWF(pi-pi) (the relationship between pi-pi overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWF(pi-pi) and BL(N-N) (nitrogen-nitrogen bond lengths) as OWF(pi-pi)=-8.1537+6.5638BL(N-N), can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules' orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).
Absorption
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Azo Compounds
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analysis
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chemistry
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radiation effects
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Computer Simulation
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Electron Transport
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radiation effects
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Light
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Models, Chemical
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Models, Molecular
4.The progress of research on low-frequency sonophoresis and its applications.
Xi TU ; Qinqin YIN ; Wensheng ZHANG ; Hua HUANG
Journal of Biomedical Engineering 2008;25(6):1474-1478
Low-frequency ultrasound can increase the transdermal delivery of many drugs, including macromolecular drugs. The main mechanism is ultrasonic cavitation. Most researchers pointed out that it could change the form-structure of stratum corneum keratinocytes and, in this way, it can improve the permeability of skin. Low-frequency sonophoresis has been in use for in-vitro experiments and in-vivo animal experiments, and so far, both small-molecules transdermal delivery and macromolecules transdermal delivery have been successfully performed in many experiments. However, there are few reports about the real low-frequency sonophoresis for clinical treatment. A large number of clinical trials are necessary to confirm its safety and practicality. Once its safety is confirmed and the suitable low-frequency sonophoresis devices are developed successfully, Low-frequency Sonophoresis will come to be a safe, effective, controllable, and economic new delivery method.
Administration, Cutaneous
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Animals
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Humans
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Skin
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diagnostic imaging
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metabolism
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Skin Absorption
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radiation effects
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Ultrasonography
5.Design of transdermal ultrasonophoresis equipment.
Liangcheng LI ; Yongshun ZHANG ; Zhonghong LI
Journal of Biomedical Engineering 2009;26(1):184-186
The recent fast development in biotechnology has resulted in a large number of therapeutic biologicals coming in the foreground for clinical application. Transdermal drug delivery (TDD) is designed for patching the drug on the skin, and then the drug molecules permeate through the skin into the subcutaneous capillary vessels. However,very few drugs can be administered transdermally at the therapeutic levels to pass through the barrier of stratum corneum. Several physical and chemical methods are applied to improve the permeability of skin. Research result shows that the low-frequency ultrasonic technique can extraordinarily increase the rate of permeation. As a result, it is becoming one of the potential methods that serve as the substitutes for traditional methods. In this paper is presented a type of equipment based on MSP430. The principle of design, the structure of hardware, and the applied function in this area are described.
Administration, Cutaneous
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Drug Delivery Systems
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instrumentation
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methods
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Equipment Design
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Humans
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Pharmaceutical Preparations
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administration & dosage
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Skin Absorption
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radiation effects
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Ultrasonics
6.A Study on the Electrophysiological Disturbance of Brain after Electromagnetic Irradiation.
Journal of the Korean Neurological Association 1996;14(3):796-809
Backgrounds : To evaluate the effects of electromagnetic wave onto the nervous system, this study introduces a method to measure the EEG of rabbits exposed to microwave fields and analyze it in compliance with theoretical specific absorption rate (SAR) distribution in the head of the rabbit obtained from the simulation study. Furthermore, the effects of nimodipine and naloxone on the EEG during the electromagnetic irradiation were reported. METHODS: 1) EEG of 20 rabbits of 2 groups was measured before and after exposure to 2.45 GHz microwave with the power density of 10 dBm and 20 dBm respectively for 10 minutes and compared with those of another 10 rabbits which have not been exposed. The result was compared with the simulation of the distribution of SAR in the 3-layered sphere model approximated from the head of rabbit 2) Another 10 rabbits were intravenously given with nimodipine before and during the irradiation. 3) Naloxone (0.25 mg/kg) was given to the other 10 rabbits which have given repeatedly exposure to microwave (twenty daily 10 min sessions). Results : The simulation of SAR distribution depicted the presence of hot-spot situated around the rabbit's thalamus and brainstem. Higher field energy of microwave (20 dBm) induced a total power reduction indicative of CNS activation and a decrease in power distribution in the delta band and an increase In the alpha and beta bands in a significant manner(P(0.05). The changes were not reversed by nimodipine-treatment. Wllen naloxone injected, 2 rabbits showed periodic theta rhythms and a clinical seizure occurred in a rabbit. Conclusion : The EEG changes suggest that microwave can alter neuronal activities in the brain, especially thalamus and brainstem. The effects may be thermal in nature arid microwave irradiation shares a common mechanism with physical and psychological stresses that also precipitate seizures.
Absorption
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Brain Stem
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Brain*
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Compliance
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Electroencephalography
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Electromagnetic Radiation
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Head
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Magnets*
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Microwaves
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Naloxone
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Nervous System
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Neurons
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Nimodipine
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Rabbits
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Seizures
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Stress, Psychological
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Thalamus
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Theta Rhythm
7.Classification of Biological Effect of 1,763 MHz Radiofrequency Radiation Based on Gene Expression Profiles.
Chang Nim IM ; Eun Hye KIM ; Ae Kyung PARK ; Woong Yang PARK
Genomics & Informatics 2010;8(1):34-40
Radiofrequency (RF) radiation might induce the transcription of a certain set of genes as other physical stresses like ionizing radiation and UV. To observe transcriptional changes upon RF radiation, we exposed WI-38, human lung fibroblast cell to 1763 MHz of mobile phone RF radiation at 60 W/kg of specific absorption rate (SAR) for 24h with or without heat control. There were no significant changes in cell numbers and morphology after exposure to RF radiation. Using quantitative RT-PCR, we checked the expression of three heat shock protein (HSP) (HSPA1A, HSPA6 and HSP105) and seven stress-related genes (TNFRSF11B, FGF2, TGFB2, ITGA2, BRIP1, EXO1, and MCM10) in RF only and RF/HS groups of RF-exposed cells. The expressions of three heat shock proteins and seven stress-related genes were selectively changed only in RF/HS groups. Based on the expression of ten genes, we could classify thermal and non-thermal effect of RF-exposure, which genes can be used as biomarkers for RF radiation exposure.
Absorption
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Cell Count
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Cellular Phone
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Fibroblast Growth Factor 2
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Fibroblasts
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Gene Expression
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Heat-Shock Proteins
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Hot Temperature
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Humans
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Lung
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Radiation, Ionizing
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Transcriptome
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Biomarkers
8.Effect of different wave-length ultraviolet light-treated micro-arc oxidation titanium surfaces on the physicochemical properties and bioactivity in vitro.
Yan GAO ; Lei ZHOU ; Ying JIANG ; Ze-hong GUO ; Hai-bin LU ; Shao-bing LI
Chinese Journal of Stomatology 2012;47(6):359-363
OBJECTIVETo study the effects of ultraviolet (UV) light-treatment on the physicochemical properties and bioactivity of micro-arc oxidation (MAO) titanium surfaces in vitro.
METHODSThe pure titanium were prepared using MAO. MAO titanium samples were treated with 15 W bactericidal lamp UVC [λ = (250 ± 20) nm] or 15 W mercury lamp [λ = (360 ± 20) nm] for 24 h under ambient conditions. Three sample groups were prepared: MAO, UVA treated after MAO (MAO + UVA), UVC treated after MAO (MAO + UVC). The surface physicochemical properties were evaluated using scanning electron microscopy (SEM), contact angle measuring device, energy dispersive X-ray spectrometer (EDX), and X-ray diffraction (XRD). Bicinchoninic acid (BCA) based colorimetric detection was used to quantify the percentage of albumin adsorption after 2 h, 6 h, and 24 h incubation on the titanium surfaces. The rates of MG-63 cells attached to each group titanium surfaces were calculated by nucleus immunofluorescence using Hoechst 33342 after 1 h, 2 h, and 4 h incubation. SEM was used to observe cell morphology on titanium surfaces in each group.
RESULTSNo obvious differences in surface topography, TiO(2) crystal and elemental composition were detected on titanium surfaces with or without UV treatment. Statistically significant difference in contact angles among MAO + UVC group (65.34 ± 1.16)°, MAO + UVA group (44.64 ± 1.28)°, and MAO group (3.41 ± 0.48)° were found (P < 0.001). The percentage of albumin adsorption reached the plateau after 2 h incubation on MAO + UVC titanium surfaces (48.16 ± 1.24)%, which was higher than those in MAO [(8.22 ± 2.99)%] and MAO + UVA groups [(5.29 ± 2.27)%, P < 0.001]. The rates of cells attached to the surfaces of MAO + UVC titanium was greater than that on MAO surfaces and MAO + UVA surfaces after 1 h [(40.71 ± 4.08)%], 2 h [(53.72 ± 2.38)%], 4 h [(70.32 ± 2.85)%] incubation (P < 0.05). The MAO + UVC surfaces remarkably enhanced the spread of MG-63 cells, however, there was no significant difference between the group of MAO and MAO + UVA.
CONCLUSIONSPretreatment of micro-arc oxidation titanium with UVC light considerably improved the surface bioactivity to MG-63 cells, which showed an increase in cellular attachment and spread.
Absorption ; Albumins ; metabolism ; Cell Adhesion ; Cell Line, Tumor ; Humans ; Microscopy, Electron, Scanning ; Osteosarcoma ; pathology ; Oxidation-Reduction ; Spectrometry, X-Ray Emission ; Surface Properties ; Titanium ; chemistry ; radiation effects ; Ultraviolet Rays ; X-Ray Diffraction