OBJECTIVETo explore the effect of static magnetic field (SMF) on the differentiation and proliferation of rat embryonic midbrain neurons cells.

METHODSThe micromass culture of rat embryonic midbrain neurons cell was applied to study the effect of varieties of SMF (1.0, 10.0, 50.0, 100.0, 200.0 mT) and FACS.

RESULTSSMF inhibited the differentiation of the cell without affecting cell proliferation. The concentration of 50% inhibition of cell differentiation (ICD(50)) was 25 mT. The concentration of 50% inhibition of cell differentiation (IVD(50)) was 45 mT.

CONCLUSIONSThe inhibition of SMF on embryonic midbrain neurons cells may be associated with impact of protein syntheses, and lipid peroxidation.

Animals ; Cell Differentiation ; radiation effects ; Cell Division ; radiation effects ; Cells, Cultured ; Electromagnetic Fields ; adverse effects ; Embryo, Mammalian ; Female ; Lipid Peroxidation ; radiation effects ; Mesencephalon ; cytology ; radiation effects ; Neurons ; cytology ; radiation effects ; Protein Biosynthesis ; radiation effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the effects of low frequency pulsed magnetic field on the proliferation and differentiation of HepG2 cells.

METHODS3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) colorimetry method and ELISA assay of alpha-fetoprotein (AFP) were used to determine the cell proliferation and differentiation after the cells were exposed to pulsed magnetic fields with different frequency but the same field intensity.

RESULTSThere were no significant differences in cell proliferation between sham and treated groups exposed to the field of 80 Hz, 1.55 mT for 1, 4, 8, 12, 24 h (P > 0.05). There were also no significant differences in cell proliferation and AFP secretion between sham and treated groups exposed to 16 Hz, 1.55 mT pulsed magnetic fields for 1, 4, 8, 24 h (P > 0.05).

CONCLUSIONThere were no "window effects" found in HepG2 cells proliferation or AFP secretion at 16 Hz and 80 Hz pulsed magnetic fields.

Cell Differentiation ; radiation effects ; Cell Division ; radiation effects ; Cell Line, Tumor ; cytology ; metabolism ; radiation effects ; Electromagnetic Fields ; Humans ; alpha-Fetoproteins ; analysis

OBJECTIVETo explore the inhibitory effect of He-Ne laser irradiation on fibroblast growth of hypertrophic scars in culture.

METHODSHe-Ne laser with wavelength of 632.8 nm, power density of 50 mW/cm(2) and doses of 3 J/cm(2), 30 J/cm(2), 90 J/cm(2) and 180 J/cm(2) was used to irradiate human scar fibroblasts in culture 1, 3 and 5 times respectively, and then the cell count and cell cycle analysis were done.

RESULTSRepeated irradiation with He-Ne laser at dose of 180 J/cm(2) three and five times led to an evident decrease in total cell number compared with that of the control group and there was a significant difference (P<0.05). The cell cycle analysis showed after three and five times of irradiation with 180 J/cm(2) He-Ne laser the cell number in S-phase decreased from 51% to 20% and 14% respectively, the cell number in G(0)/G(1) phase increased from 28% to 55% and 60% respectively, and the cell percentage in Sub-G1 phase was 6.7% and 9.8% respectively.

CONCLUSIONSRepeated irradiation with 180 J/cm(2) He-Ne laser can inhibit scar fibroblasts growth in culture. It may be that He-Ne laser irradiation causes cell stagnation in G(0)/G(1) phase and apoptosis.

Cell Division ; radiation effects ; Cells, Cultured ; Cicatrix ; pathology ; Dose-Response Relationship, Radiation ; Female ; Fibroblasts ; cytology ; radiation effects ; Helium ; Humans ; Lasers ; Male ; Neon

OBJECTIVETo seek for the appropriate concentration, at which IGF-II can exerts its strong effects on postirradiation proliferation, physiological function and differentiation of the rat's osteoblast-like cells (ROB).

METHODSThe osteoblast-like cells used were isolated from the calvariae of neonatal (one-day-old) SD rats by sequential enzymatic digestion. The third passages of the cells were irradiated with gamma-ray from a (60)Co source at the doses of 100, 400, 600, and 900 cGy. The medium was changed immediately after irradiation and 5 concentrations of IGF-II, i.e., 0, 0.1, 1.0, 10.0, and 100.0 microgram/L were added. 6 days after radiation (9 days in culture), the examination, or the measurement of relative cell number, was carried out.

RESULTSRadiation inhibited the ROB, even lethally. IGF-II completely counteracted the inhibitory effects when the cells were exposed to the radiation at lower dose (100 cGy), and partially when at higher dose (400 cGy). But after the radiation at much higher dose as 900 cGy, the damages were irreversible, even with the existence of this growth factor.

CONCLUSIONSAt least a portion of effective recovery of postirradiation damages may be due to IGF-II-induced radioresistance. Incubation with IGF-II can increase radioresistance or repair of radiation-induced cells damages. However, this effect depends on the dose of radiation.

Animals ; Cell Division ; drug effects ; radiation effects ; Cells, Cultured ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Insulin-Like Growth Factor II ; pharmacology ; Osteoblasts ; drug effects ; physiology ; radiation effects ; Radiation Tolerance ; drug effects ; Rats ; Rats, Sprague-Dawley

A quantitative assay was performed on the effects of gamma-irradiation (30-300 Gy) on intracellular proliferation of Toxoplasma gondii RH tachyzoites in human leukemic HL-60 cells and murine peritoneal macrophages by means of 3H-uracil uptake assay. Infected non- irradiation group (NI) and uninfected group (incubating only host cells) were prepared. The 3H-uracil uptake by tachyzoites of NI group 12-24 hrs after infection was 2,190-4,787 counts per minute for macrophages and 2,967-8,254 for HL-60 cells, whereas the irradiated tachyzoites revealed only 381-703 (100 Gy) and 218-408 (300 Gy) for macrophages, and 1,911-2,618 (30 Gy), 1,253-1,384 (70 Gy), 1,013-1,090 (100 Gy), and 483-588 (300 Gy) for HL-60 cells. The proliferation inhibition rate was similar in macrophages and HL-60 cells, for example, 89-94% and 80-94% respectively by 300 Gy, 12-24 hrs after infection. It is concluded that RH tachyzoites of T. gondii are severely affected by gamma-irradiation in their capability of intracellular proliferation.
Animal ; Cell Division/RADIATION EFFECTS ; Cells, Cultured ; Gamma Rays ; Human ; HL-60 Cells/PARASITOLOGY ; Macrophages/PARASITOLOGY ; Mice ; Mice, Inbred BALB C ; Mice, Inbred ICR ; Radiation Dosage ; Support, Non-U.S. Gov't ; Toxoplasma/*RADIATION EFFECTS/*CYTOLOGY

Based on the characteristics of metabolism of photosynthetic bacteria and the major kinds of organic compounds produced in wastewater degradation, eleven kinds of organic compounds were chosen for hydrogen photoproduction using Rhodopseudomonas palustris Z strain. The maximal volumetric H2 productivity was obtained using acetate as the sole carbon source and electron donor. The kinetics of cell growth and H2 liberation, and the influences of several major limiting factors on photoevolution of H2 were examined using acetate as carbon source. It was shown that hydrogen production was partially correlated with cell growth. The medium composition of the preculture, the preculture time, and inoculation volume were confirmed to have big effects on hydrogen photoevolution. The time delay of H2 production was evidently shortened using the inoculum of late exponential growth phase or stationary phase using ammonium sulfate as nitrogen source or with the inoculum of middle exponential growth phase using glutamate as the nitrogen source. The identity of temperature and light intensity for H2 evolution and cell growth has significant potential application in the technology of splitting organic acid into H2 by photosynthetic bacteria. The concentrations of acetate and glutamate in the medium affected hydrogen photoevolution and cell growth significantly. The productivity of H2 increased with substrate concentrations when substrate concentrations of sodium acetate and sodium glutamate were lower than 70 mmol/L and 15 mmol/L, respectively. Hydrogen production was inhibited but the cell growth was faster when the concentration of sodium glutamate over 15 mmol/L due to forming free NH4+. The highest rate of hydrogen production was 19.4 mL.L-1.h-1 using 30 mmol/L of sodium acetate as hydrogen donor under the standard conditions, respectively. The optimal conditions for hydrogen production were 35-37 degrees C, 6000-8000 lx and pH 7.3-8.3. The effects of oxygen and inoculation volume on photoproduction of hydrogen were also discussed.
Acetates ; metabolism ; pharmacology ; Cell Division ; drug effects ; radiation effects ; Dose-Response Relationship, Drug ; Glutamic Acid ; metabolism ; pharmacology ; Hydrogen ; metabolism ; Hydrogen-Ion Concentration ; Light ; Oxygen ; pharmacology ; Rhodopseudomonas ; drug effects ; metabolism ; radiation effects ; Temperature ; Time Factors

OBJECTIVETo investigate the effect of SS8, a monomer extracted from Spatholobus suberectus Dunn used for invigorating the circulation of blood, on proliferation of hematopoietic progenitor cells in mice with bone marrow depression.

METHODThe method of semi-solid culture with methylcellulose of CFU-GM, CFU-E, BFU-E, CFU-Meg was adopted in bone marrow depressed mice which were treated with SS8 for a long time.

RESULTThe experimental data demonstrated that the numbers of CFU-GM, CFU-E, BFU-E, CFU-Meg in bone marrow depressed mice were raised distinctly under the control of SS8 as compared with those of contrast group. The effect of SS8 became stronger as time went on and the dosage rose.

CONCLUSIONSS8 can distinctly stimulate the proliferation of hematopoietec progenitor cells in mice with bone marrow depression in a time-and-dosagedependent manner.

Animals ; Bone Marrow Cells ; radiation effects ; Cell Division ; drug effects ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Erythroid Precursor Cells ; drug effects ; radiation effects ; Fabaceae ; chemistry ; Female ; Hematopoietic Stem Cells ; cytology ; drug effects ; radiation effects ; Male ; Mice ; Plants, Medicinal ; chemistry ; Whole-Body Irradiation

OBJECTIVETo observe the effect of RNA interference on CHK1 and CHK2 expression and change of G2/M phase arrest in esophageal carcinoma cells after irradiation.

METHODSFour sequences short hairhip RNA (shRNA) of each CHK1 and CHK2 genes were constructed and connected with vector of pENTR/U6 plasmid, respectively, and then transfected into Eca109 cells with lipofectamine 2000 reagent. Protein and mRNA expression of CHK1 and CHK2 genes were detected with Western blotting and RT-PCR, respectively. Cell cycling was measured by flow cytometry after 5 Gy irradiation. Cell survival rate after 5 Gy irradiation was evaluated by clonegenetic assay.

RESULTSFour shRNA vector each of CHK1 and CHK2 genes were successfully constructed and transfected into Ecal09 cells, respectively. Protein expression of CHK1 and CHK2 were obviously decreased. Their mRNA expressions were also decreased after transfected with shRNA of CHK1 and CHK2. Arrest of G2/M stage in Eca109 cells were obviously decreased only in cells transfected with CHK1 shRNA but not with CHK2 shRNA at 12 h after 5 Gy irradiation. In first progeny Eca109 cells transfected with CHK1 and CHK2 shRNA, expression of CHK1 and CHK2 protein was also decreased. The level of phosphorylated CHK2-T68 expression was decreased at 1 h after 5 Gy irradiation, and at 72 h only transfected with CHK2 shRNA but not with CHK1 shRNA. Phosphorylation level of CHK1-S345 was not increased after transfected with CHK1 or CHK2 shRNA, but arrest of G2/M stage still remained at 12 h after 5 Gy irradiation and at 72 h accordingly. The cell survival rate was decreased in Eca109 cells transfected with CHK1 or CHK2 shRNA after 5 Gy irradiation.

CONCLUSIONAfter transfected with shRNA of CHK1 or CHK2, their expressions of mRNA and protein in Ecal09 cells are markedly inhibited and this inhibition effect can be observed in their first progeny cells and at least hold for 3 days. Arrest of G2/M phase can be reduced after irradiation when teansfected with shRNA of CHK1 and the radiosensitivity of Ec109 cells can be increased.

Blotting, Western ; Cell Division ; genetics ; physiology ; radiation effects ; Cell Line, Tumor ; Cell Survival ; genetics ; physiology ; radiation effects ; Checkpoint Kinase 1 ; Checkpoint Kinase 2 ; Esophageal Neoplasms ; genetics ; pathology ; physiopathology ; G2 Phase ; genetics ; physiology ; radiation effects ; Gamma Rays ; Genetic Vectors ; Humans ; Protein Kinases ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

To evaluate the effect of Ligustrazine on the expression of VEGF in bone marrow stromal cells (BMSCs) of radiation injured mice and to explore the effect of VEGF on the recovery of hematopoiesis and the mechanism of signal transduction, the protein expression of VEGF, focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) in BMSCs were assayed by Western blot, the cell cycle and apoptosis rate of BMSCs were tested by flow cytometry. The effect of Ligustrazine on the hematopoiesis was evaluated at the same time. The results showed that the protein expression of VEGF in BMSCs was decreased significantly after irradiation and increased slowly with the time. The value in Ligustrazine-treated group almost reached normal level, but it remained lower than that in control group on day 14. The changes of phosphorylated FAK and MAPK protein expression had the same tendency. After (60)Co gamma-irradiation, the BMSCs were arrested in G0-G1 phase and apoptosis rate increased; these values recovered slowly with the time and remained higher than that in normal control group on day 14. The recovery of these values in Ligustrazine-treated group was sooner than that in irradiated control group, and they almost reached to the normal levels on day 14. It is concluded that irradiation could inhibit the expression of VEGF in BMSCs and induce apoptosis. The Ligustrazine promotes the recovery of bone marrow microenvironment probably by increasing the expression of phosphorylated FAK and MAPK in BMSCs.
Animals ; Apoptosis ; drug effects ; Bone Marrow Cells ; drug effects ; metabolism ; Cell Cycle ; drug effects ; Cell Division ; drug effects ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Mice ; Protein-Tyrosine Kinases ; analysis ; Pyrazines ; pharmacology ; Radiation Injuries, Experimental ; drug therapy ; metabolism ; Radiation-Protective Agents ; pharmacology ; Stromal Cells ; drug effects ; metabolism ; Vascular Endothelial Growth Factor A ; analysis

OBJECTIVESince most reports on bystander effect have been only concerned with radiation-induced damage, the present paper aimed at disclosing whether low dose radiation could induce a stimulatory or beneficial bystander effect.

METHODSA co-culture system containing irradiated antigen presenting cells (J774A.1) and unirradiated T lymphocytes (EL-4) was established to observe the effect of J774A.1 cells exposed to both low and high doses of X-rays on the unirradiated EL-4 cells. Incorporation of 3H-TdR was used to assess the proliferation of the EL-4 cells, expression of CD80/86 and CD48 on J774A.1 cells was measured with immunohistochemistry and flow cytometry, respectively. NO release from J774A.1 cells was estimated with nitrate reduction method.

RESULTSLow dose-irradiated J774A.1 cells could stimulate the proliferation of the unirradiated EL-4 cells while the high dose-irradiated J774A.1 cells exerted an inhibitory effect on the proliferation of the unirradiated EL-4 cells. Preliminary mechanistic studies illustrated that the differential changes in CD48 expression and NO production by the irradiated J774A.1 cells after high and low dose radiation might be important factors underlying the differential bystander effect elicited by different doses of radiation.

CONCLUSIONStimulatory bystander effect can be induced in immune cells by low dose radiation.

Animals ; Antigen-Presenting Cells ; immunology ; metabolism ; radiation effects ; Antigens, CD ; immunology ; B7-1 Antigen ; immunology ; B7-2 Antigen ; Bystander Effect ; radiation effects ; Cell Division ; immunology ; Cell Line ; Coculture Techniques ; Dose-Response Relationship, Radiation ; Membrane Glycoproteins ; immunology ; Mice ; Nitric Oxide ; biosynthesis ; T-Lymphocytes ; immunology ; X-Rays