Objective To investigate the cause of continuous cropping obstacle of Rehmannia glutinosa and screen beneficial bacteria.Methods In vitro cultured plantlets and potted plants were inoculated with different isolated soil bacteria. The plants were harvested and weighted in 30 and 60 d,respectively.Results In the in vitro culture experiment,11 out of 48 strains displayed promoting action on the growth of plantlets,and 11 other strains showed inhibitory or lethal action.In the potted test,16 strains showed promoting action and 13 strains showed suppressing or lethal action.Conclusion Soil bacteria influence the growth of R.glutinosa significantly.The flora of rhizosphere bacteria may be disturbed by the cultivation of R.glutinosa and inoculation of beneficial bacteria might be effective on the resolution of continuous cropping obstacle of R.glutinosa.

Object To investigate the saccharide changes of Radix Rehmanniae when being processed. Methods The fresh roots were torrefied at 65 ℃ and sampled at 0,1, and 6 d. The samples and 4 h steamed slices of those dried roots were extracted with hot water respectively. The extracts were subjected to HPLC analysis, Sugar pak 1 column at 80 ℃,with water as the mobile phase at 0 7 mL/min and detected by RID. Results There are three principal components in the fresh roots, i.e. stachyose (11%-15%), sucrose (0 30%-0 92%), and catalpol (0 27%-0 88%). In the processing of the fresh roots, the HPLC chromatorams of the extracts differed to each other remarkbly. On the chromatogram of roots torrefied for 1 d, one distinct monosaccharide peak displayed at 10 2 min, which is likely to be galactose, and it become prominent in the dried roots together with raffinose. In steamed ones, the peaks of fructose and glucose became outstanding. Conclusion According to the HPLC chromatograms, the degalacto sylation of stachyose may take place during torrifying, while defructosylation during steaming. One of the principal purposes of the processing may be for stachyose degradation for its flatulence causing character.

Objective To observe the damaging effect of microwave on neurons and the protective effect of selenium on damaged neurons after exposure to microwave. Methods In vitro cultured PC12 cells were exposed to 65 mW/cm 2 microwave. The survival rate, SOD activity, GSH-Px activity, and MDA concentration of PC12 cells were detected. The effects of selenium on PC12 cells after exposure to microwave were reflected by these markers. Results Survival rate, activity of superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity of PC12 cells decreased, but malondialdehyde (MDA) concentration of PC12 cells increased after microwave radiation. These changes weakened when PC12 cells were exposed to microwave after pretreatment with selenium. This effect was more significant after pretreatment with selenium at the high dose. Conclusion PC12 cells can be damaged by microwave through peroxidation. Selenium pretreatment can promote the antioxidation and protect PC12 cells from damages induced by microwave.

Object To develop a method of multiplying virus free clonal seedlings of CV.85 5 of Rehmannia glutinosa (Gaert.) Libosch. ex Fisch. et Mey.. Methods The leaf cut segments with or without tips of plantlets were grown in different media (mg/L) (1.MS+BA 0.5; 2 MS+BA 0.5+NAA 0.02;3 MS+BA 0.5+NAA 0.02+GA 3 0.1; 4 1/2 MS+BA 0.1; 5 1/2 MS+BA 0.1+GA 3 0.1; 6.1/2 MS+GA 3 0.1) to select a suitable medium, and the height and the numbers of newly formed leaves and roots were recorded 30 days later. To screen out a favorable condition, similar segments were transferred to No.2 medium at different temperatures in different illuminations, and the height together with the leaf number and the fresh weight of the plantlets was recorded.Results In the former three media, the segments with tips were flourishing and one to three axillary buds were formed at its basal stem; while in those without tips almost every axillary bud developed with the main tip length 0.5～1.5 cm. In the later three media, thd elongation of the segments was usually overstimulated, and the slim plantlets with fewer leaves and more roots formed. When the segments cultured in No.2 medium, all records at 28 ℃ were higher than those at 23 ℃ in the same illuminations. But the leaf size and the height of the plantlets were inversely proportional to the intensity of illumination at the same temperature. In addition, antagonism between BA and GA 3 was found.Conclusion No.2 medium is more suitable for the multiplication of the virus free seedlings of 85 5 when cultured at 28 ℃ in the illumination of 1 000～2 000 lx.

Objective To establish a less-damage method for tracheal intubation so as to improve the quality of post-cardiac arrest syndrome.Methods Thirty rabbits wvere divided into 3 groups of 10 rabbits each according to the random number table:group A receiving direct endotracheal intubation after anesthesia,Group B separation of cervical tissue and retrograde tracheal intubation after anesthesia and Group C percutaneous retrograde tracheal intubation after anesthesia.After the intravenous injection of forskolin,cardiac arrest was induced by endotracheal tube clamping.After 5 minutes of untreated arrest,conventional cardiopulmonary resuscitation was initiated.Changes in arterial pressure,occurrence of post-resuscition syndrome and survival time were examined in all groups.Results Groups A,B and C showed 40％,60％ and 80％ success rate in cardiopulmonary resuscitation (P ＜ 0.01) and animal survival time of 23.4 hours (11.6-35.8 hours),62.7 hours (29.4-88.6 hours) and 79.5 hours (40.9-118.2 hours) (P ＜ 0.01).Conclusions Percutaneous retrograde tracheal intubation is suitable to increase cardiopulmonary resuscitation rate and survival rate in rabbits with post-cardiac arrest.The model has good stability and repeatability and can be used for study of post-cardiac arrest syndrome.

OBJECTIVETo study the role of catecholamine(CA) in the mechanism of bio-effect of electromagnetic irradiation.

METHODSThe contents of norepinephrine (NE), epinephrine (E) and dopamine (DA) in serum and hippocampus of rats at 0, 8, 24, 48 hours after electromagnetic irradiation were measured by using high performance liquid chromatography with electrochemical detector(HPLC-ECD), and the influence of two kinds of shelter on CA was studied.

RESULTSThe levels of CA in serum and hippocampus increased obviously in an instant, decreased at 8 h and increased significantly again at 24 h after irradiation without shielding irradiation. But at 48 h, the levels of NA, DA in hippocampus were still higher and the serum's NA, DA were not different from the control. After irradiation with whole body shielding, the levels of CA had no changes. The contents of CA increased significantly only at 24 h after irradiation by 65 W/cm2 electromagnetic wave with trunk shielding. After irradiation by 129 W/cm2 with trunk shielding, the change of CA were similar to that of no shielding.

CONCLUSIONCA may take part in the injury to central nervous system and cardiovascular system after electromagnetic irradiation. And the injury to central nervous system may sustain longer than that of cardiovascular system. The protective effect of whole body shielding is the best, while trunk shielding may have some protective effect following lower and middle power electromagnetic wave. The most important protective measure is to shield the head.

Animals ; Catecholamines ; analysis ; blood ; Chromatography, High Pressure Liquid ; Electrochemistry ; Electromagnetic Phenomena ; Hippocampus ; chemistry ; radiation effects ; Rats

Objective To investigate the effect and the mechanism of nifedipine on oxidative stress trip-ping by iron-overload of HK-2 cells. Methods The cells were divided into 4 groups,blank group,iron overload group,nifedipine group and FAC with nifedipine co-treatment group. Cells were treated with FAC or/and nifedipine for 24 hours,and then malonaldehyde (MDA) content,superoxide dismutase (T-SOD) activity,glutathione (GSH) content,intracellular iron content and expression of DMT1 and FPN1 protein were evaluated. Results Compared to the iron overload group,both nifedipine treatment and co-treatment decreased the content of MDA (P < 0.05),increased the activity of SOD(P < 0.05),increased the content of GSH(P < 0.05),reduced the intracellular iron content(P<0.05),increased the expression of DMT1(P<0.05),and increased the expression of FPN1(P < 0.05). Conclusion Nifedipine plays a protective role against oxidative stress induced by iron-overload in HK-2 cells,and it is related to promote DMT1 and FPN1 protein expression and reduce intracellular iron content.

Objective To investigate the effect and underlying mechanism of roxadustat on apoptosis and senescence of renal tubular epithelial cell line HK-2 induced by heat stress.Methods After HK-2 cells were treated with different concentrations of roxadustat(10,20,30,40 and 50 μmol/L)for 24 h,CCK-8 assay was used to determine the optimal intervention concentration of roxadustat.HK-2 cells were divided into 4 groups(n=3):control group,roxadustat group(30 μmol/L,24 h),heat-stress group(43 ℃,2 h),and heat-stress+roxadustat group(30 μmol/L roxadustat treatmnet for 24 h followed by heat-stress 2 h).Cell viability was detected by CCK-8 assay.Expression of hypoxia-inducible factor-1α(HIF-1α),Cleaved Caspase-3,p16 and p21 at protein level was detected by Western blotting.Immunofluorescence assay was employed to observe the distribution of HIF-1α.β-galactosidase staining kit was utilized to detect SA-β-Gal activity.TUNEL staining was used to measure cell apoptosis.Results The highest cell viability was observed in the cells after 30 μmol/L roxadustat treatment.Heat stress resulted in a significant decrease in cell viability(P＜0.05),elevated protein levels of HIF-1α,Cleaved Caspase-3,p16 and p21(P＜0.05),enhanced SA-β-Gal activity(P＜0.05)and increased percentage of TUNEL-positive cells(P＜0.05)when compared with the cells in the control group.In comparison with the heat-stress group,the heat-stress+roxadustat group showed significant decrease in the protein levels of Cleaved Caspase-3,p16 and p21(P＜0.05),reduced activity of SA-β-Gal[(65.44±5.00)％vs(77.15±2.61)％,P＜0.05]and decreased percentage of TUNEL-positive cells[(16.73±2.20)％vs(46.40±13.87)％,P＜0.05],but increase in cell viability[(86.33±4.51)％vs(66.33±8.50)％,P＜0.05]as well as HIF-1α protein expression(P＜0.05).Furthermore,immunofluorescence assay showed that HIF-1α was mainly distributed in the nucleus and perinucleus.Conclusion Roxadustat attenuates heat stress-induced apoptosis and senescence of renal tubular epithelial cells by upregulating HIF-1α.