OBJECTIVEPresent study was conducted to explore the growth and photosynthetic characteristics of Tulipa edulis under different light conditions (23%, 45%, 63%, 78%, 100% of full sunlight) and to determine the optimum light intensity for growth of T. edulis.

METHODThe leaf area and biomass indicators as well as reproductive characteristics were measured. The photosynthetic basic parameters and light response curve were determined by a LI-6400XT portable photosynthesis system, and the light response curve characteristic parameters was determined. Additionally, chlorophyll fluorescence parameters were determined by assorted fluorescence leaf chamber of LI-6400XT.

RESULTThe lowest biomass yield was observed in the 23% and 100% of full sunlight treatments while the highest value was found under the 78% of full sunlight conditions. With the reduction of light availability, the success rate of sexual reproduction, light saturation point (LSP) and light compensation point (LCP) reduced, while apparent quantum yield (AQY) increased. 23% and 45% of full sunlight treatments led to lower photosynthesis rate (Pn) and higher apparent quantum yield (AQY) in comparison with other treatents. The highest photosynthesis rate was observed in the 78% and 100% of full sunlight treatments. In addition, 78% of full sunlight treatments led to highest Fv/Fm, Fv'/Fm', PhiPS II, ETR, and qP.

CONCLUSIONT. edulis was able to adapt in a wide range of light intensity, and 78% of full sunlinght was the most suitable light condition for growth of T. edulis.

Biomass ; Dose-Response Relationship, Radiation ; Photosynthesis ; radiation effects ; Sunlight ; Tulipa ; growth & development ; metabolism ; radiation effects

Dose-Response Relationship, Radiation ; Humans ; Radiation, Ionizing ; Radiation, Nonionizing ; adverse effects

An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19 degrees C, 24 degrees C and 27 degrees C in glasshouses. Five different colour filters (i.e. 'Red absorbing', 'Blue absorbing', 'Blue and Red absorbing' and two 'partially Blue absorbing' materials) were tested, with one clear polythene as a control. Plant height, internode length and leaf area were significantly affected by the spectral filters as well as the temperature. Analysis of color filter's effect on presumed photoreceptors to exist indicated that antirrhinum plant height was regulated by the action of a blue acting photoreceptor (BAP) and not the phytochrome. There was no evidence for an effect of phytochrome or BAP on time to flowering, however, increasing temperature levels effectively decreased the time to flowering. To predict the effects of different spectral qualities and temperature, simple models were created from data on plant height, internode length and time to flowering. These models were then applied to simulate the potential benefits of spectral filters and temperature in manipulation of growth control and flowering in antirrhinum.
Antirrhinum ; growth & development ; radiation effects ; Dose-Response Relationship, Radiation ; Light ; Radiation Dosage ; Temperature

This paper describes the development of TBI technique about fractionated TBI and the relationship between irradiation dose rate and complication; IMRT for TBI and lung compensation technique.
Dose-Response Relationship, Radiation ; Humans ; Radiation Dosage ; Whole-Body Irradiation ; methods

OBJECTIVETo investigate the injuries of intestinal mitochondria induced by different doses of whole-body radiation in Tibet minipigs.

METHODSEighteen Tibet minipigs were randomized into 5 radiation groups (n=3) and a control group (n=3). The minipigs in the radiation groups were subject to a total body X-ray radiation at 2, 5, 8, 11, or 14 Gy, and 72 h after the exposure, the mRNA expressions of the intestinal mitochondrial genes were examined using RT-PCR. The changes in the respiratory chain complexes I-IV and the respiratory functions of succinate and NADH were assayed, and the intestinal ultrastructures were observed using transmission electron microscopy (TEM) following the exposures.

RESULTSCompared with those in the control group, the expression levels of the related mitochondrial genes, the activities of the respiratory chain complexes and the function of the respiratory chain were significantly lowered in the radiation groups. At the doses below 8 Gy, the exposures caused significant reduction in the measurements as the radiation doses increased, but at higher doses, these measurements showed no further reductions. Ultrastructurally, exposures at 2 and 5 Gy caused mitochondrial expansion and mild reduction of the density, whereas radiation at 8 Gy or greater resulted in vacuolar changes and obvious expansion of the mitochondria with damages of the mitochondrial cristae and membranes.

CONCLUSIONBelow the doses of 8 Gy, intestinal mitochondrial damages in the minipigs increase with the radiation dose, but at higher doses, the damages do not further increase with the radiation dose.

Animals ; Dose-Response Relationship, Radiation ; Intestines ; cytology ; radiation effects ; Male ; Mitochondria ; radiation effects ; Radiation Dosage ; Swine ; Swine, Miniature

OBJECTIVETo investigate the effect of the photodynamic therapy (PDT) with the new water-soluble metalloporphyrin compound on human prostate cancer PC-3 cells in vitro and the anticancer mechanism of PDT.

METHODSThe new water-soluble manganese, 5,10,15, 20-tetra (N-methyl4-pyridyl) porphinato (2-) tetraiodide salt, was synthesized. The PC-3 cells were treated with the compound of serial concentrations(0, 0.1, 1, 1.0 micromol/L) followed by irradiation of different dosages of visible light. The techniques of MTT and Annexin-V/propidium iodide double-labeled flow cytometry (FCM) were applied to measuring the inhibitory effect of the compound on the growth activity and apoptosis of the cells.

RESULTSWhen the metalloporphyrin compound concentration was within 10 micromol/L and the irradiation time was within 30 min, the water-soluble metalloporphyrin compound had a significant inhibitory effect on the proliferation of PC-3 cells and induced PC-3 cell apoptosis, and the effects depended greatly on metalloporphyrin concentration and illumination dosages. Higher concentrations and dosages induced the death of the majority of PC-3 cells.

CONCLUSIONThe PDT of the water-soluble metalloporphyrin compound followed by light irradiation has a distinctive killing effect on PC-3 cells in vitro, and the rates of proliferation inhibition and cell apoptosis are correlated with metalloporphyrin concentration and the dosages of light irradiation. The results suggest that the mechanism of metalloporphyrin PDT may be involved with the induction of apoptosis in human prostate cancer cells.

Apoptosis ; drug effects ; radiation effects ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Humans ; Male ; Metalloporphyrins ; pharmacology ; Photochemotherapy ; Prostatic Neoplasms ; pathology

Effects of gamma irradiation on the worm survival and chromosomal aberration of Clonorchis sinensis were studied. The metacercariae irradiated with various amounts of gamma radiation (ranging from 5 Gy to 50 Gy) were fed to rats, and the effects were compared with those of non-irradiated controls. Recovery rates of adult worms in irradiated groups were reduced gradually as increasing of the irradiation doses. No worm was recovered from rats which were fed with 50 Gy irradiated metacercariae. The chromosome number was 2n = 56 in all worms from all experimental groups. However, the groups irradiated with 20 Gy, 25 Gy or 30 Gy showed variations in the chromosome number, depending on different cells in the same individual. Radiation doses used in this study did not appear to induce chromosome aberrations, however, irradiation with 30 Gy showed slightly reduced chromosome size.
Animals ; Chromosome Aberrations/*radiation effects ; Clonorchis sinensis/*genetics/physiology/*radiation effects ; Dose-Response Relationship, Radiation ; Gamma Rays/*adverse effects ; Rats

BACKGROUNDIrradiation dose and volume are the major physical factors of radiation-induced lung injury. The study investigated the relationships between the irradiation dose and volume in radiation-induced lung injury by setting up a model of graded volume irradiation of the rat lung.

METHODSAnimals were randomly assigned to three groups. The ELEKTA precise 2.03 treatment plan system was applied to calculate the irradiation dose and volume. The treatment plan for the three groups was: group 1 received a "high dose to a small volume" (25% volume group) with the mean irradiation volume being 1.748 cm(3) (25% lung volume); the total dose and mean lung dose (MLD) were 4610 cGy and 2006 cGy, respectively (bilateral AP-PA fields, source to axis distance (SAD) = 100 cm, 6MVX, single irradiation); Group 2 received a "low dose to a large volume" (100% volume group) with the mean irradiation volume being 6.99 cm(3) (100% lung volume); the total dose was 1153 cGy. MLD was 2006 cGy, which was the same as that of group 1 (bilateral AP-PA fields, SAD = 100 cm, 6MVX, single irradiation); Group 3 was a control group. With the exception of receiving no irradiation, group 3 had rest steps that were the same as those of the experimental groups. After irradiation, functional, histopathological, and CT changes were compared every two weeks till the 16th week.

RESULTSFunctionally, after irradiation breath rate (BR) increases were observed in both group 1 and group 2, especially during the period of 6th - 8th weeks. The changes of BR in the 100% volume group were earlier and faster. For the 25% volume group, although pathology was more severe, hardly any obvious increase in BR was observed. Radiographic changes were observed during the early period (the 4th week) and the most obvious changes manifested during the mediated period (the 8th week). The extensiveness of high density and the decreased lung permeability were presented in the 100% volume group, and ground glass opacity and patchy consolidation were presented in the 25% volume group without pleural effusion, pleural thickening, and lung shrinking. Morphologically, the 100% volume group mainly presented signs of vascular damage, including signs of vascular wall edemas, hypertrophy, and sclerosis. The 25% volume group mainly presented with erythrocyte cell exudation, inflammation, and parenchymal damage.

CONCLUSIONSThe delivery of a small dose of radiation to a large volume is not safe. A low dose smeared out over large volumes, albeit reversible, may lead to fatal respiratory dysfunction. Damage to the lung may be more dependent on the volume of irradiation than on the radiation dose. Clinically, the safest approach is to limit both the volume of the irradiated normal lung and the amount of received radiation.

Animals ; Dose-Response Relationship, Radiation ; Lung ; radiation effects ; Lung Injury ; etiology ; Radiation Injuries, Experimental ; Rats ; Rats, Wistar

OBJECTIVETo investigate radiation protection and possible mechanisms of low intensity microwave on gamma-ray exposed mice.

METHODS96 healthy Kunming mice were randomly divided into the following four groups: normal control, microwave (120 microW/cm(2), 900 MHz), gamma-ray irradiation (5 Gy), combined exposure of microwave and gamma-ray (120 microW/cm(2) + 5 Gy). The microwave group and combined group were exposed to 120 microW/cm(2) microwave firstly, 1 h/d, for 14 days. Then the ionization and combined group were exposed to 5 Gy (60)Co gamma-ray irradiation on the 15th day. Animals were sacrificed on the third, 6th, 9th and 12th day after irradiation. The sternum and spleen paraffin section were produced, and the histological changes were observed. Apoptosis rate of mice splenic cells in each group was examined by flow cytometry, and serum concentration of antioxidant and lipid peroxide was detected at the same time.

RESULTSBone marrow was obviously injured either by radiation or microwave exposure, characterized by undergoing four-phase lesions, namely apoptosis-necrosis, void, regeneration and recovery phase. Compared with the gamma-ray group, the pathological changes in combined group were slighter and the recovery was quicker. The pathological injuries of spleen were similar to that of bone marrow. Injuries in the combined group were slighter than gamma-ray group. It showed that apoptosis rate of splenic cells in combined group was significantly lower on the 6th and 9th day after gamma-ray radiation (23.02% +/- 15.18%, 25.37% +/- 11.62% respectively) from FCM results. Assays of oxidative damages suggested that serum superoxide dismutase (SOD) level in combined group increased while lipid peroxide level decreased significantly (P < 0.05).

CONCLUSIONLow intensity microwave may exert protection effects on injuries induced by ionizing radiation. The underlying mechanisms might be related with suppression on the hematopoietic cells apoptosis induced by gamma-ray radiation, inhibition of oxidative damages, and thus enhanced reconstruction of the hematopoietic system.

Animals ; Apoptosis ; radiation effects ; Dose-Response Relationship, Radiation ; Gamma Rays ; adverse effects ; Male ; Mice ; Microwaves ; Radiation Protection

OBJECTIVETo explore the pathological characteristics and the dynamic change regularity of the testis induced by high power microwave (HPM) radiation.

METHODSOne hundred and sixty-five male Wistar rats were exposed to 0, 3, 10, 30 and 100 mW/cm2 HPM radiation for five minutes, and changes of testicular morphology and teratogenic ratio of epididymal spermatozoa were observed through light microscope and electron microscope at 6 h, 1, 3, 7, 14, 28 and 90 d after radiation.

RESULTSInjury of testicular spermatogenic cells in rats might be induced by 3 to approximately 100 mW/cm2 HPM radiation, and the main pathological changes were degeneration, necrosis, shedding of spermatogenic cells, formation of multinuclear giant cells, decrease or loss of sperm and interstitial edema. Injury of spermatogenic cells underwent such phases as death and shedding, cavitation, regeneration and repair, characterized by being focalized, inhomogenous and phased. And the severity of pathological changes of the testis increased with power density. There was only scattered degeneration, necrosis, shedding of spermatogenic cells in the seminiferous tubule one day after 3 mW/cm2 radiation, and the pathological changes six hours after 10 mW/cm2 radiation was similar to those one day after 3 mW/cm2 radiation, but with the formation of multinuclear giant cells, and the above-mentioned pathological changes aggravated from one day to seven days after radiation. There was a significant increase in degeneration, necrosis, shedding of spermatogenic cells, as well as a significant decrease in spermatozoa and focal necrosis in simple seminiferous tubules six hours after 30 and 100 mW/cm2 radiation, and the subsequent changes were similar to those of 10 mW/cm2 radiation. There was a significant increase in teratogenic ratio of epididymal spermatozoa at 3 d, 1 to approximately 7 d, 6 h to approximately 7 d after 3, 10, 30 and 100 mW/cm2 microwave radiation respectively (P < 0.01 or P < 0.05).

CONCLUSIONHPM radiation may cause injury of testicular spermatogenic cells in rats, which has a positive correlation to radiation dosage and time.

Animals ; Dose-Response Relationship, Radiation ; Male ; Microwaves ; Rats ; Rats, Wistar ; Spermatozoa ; pathology ; radiation effects ; Testis ; pathology ; radiation effects