Biomedical subjects

Ping Lu

Publications and source records attributed to Ping Lu.

79 records · Page 5Linked to original sources

PubMed2002

Joint enhancement of lead accumulation in Brassica plants by EDTA and ammonium sulfate in sand culture.

When EDTA was added alone in the Pb-contaminated sand, the plant biomass and the total Pb amount in Plant decreased in both species, Brassica pekinensis and B. juncea var. multiceps, though the shoot Pb amount increased. In contrast, when (NH4)2SO4 was added alone in the Pb-contaminated sand, little effect was observed on the shoot Pb amount, though the root Pb amount was significantly increased in B. juncea var. multiceps. When amending EDTA and (NH4)2SO4 in combination, however, the shoot Pb amount in both species substantially increased, being, on an average, 2 times and 9 times higher than that in EDTA alone or (NH4)2SO4 alone amended treatment, respectively. The two amendments showed antagonism for plant growth, but synergism for Pb bioaccumulation. B. pekinensis showed its highest level of shoot and total Pb amount in the treatment amended with EDTA and (NH4)2SO4 only a half as much as in the other treatments. It is inferred that the mechanisms responsible for the joint-enhanced Pb accumulation might be concerned with the acidification of the growth medium, cation exchange reaction and relieving EDTA induced toxicity as results by amending ammonium sulfate.

Ammonium Sulfate↗

PubMed2002

[Soil catalase activity of main plant communities in Leymus chinensis grassland in northeast China].

The seasonal dynamics of soil catalase activity of three different plants communities in Leymus chinensis grassland in northeast China were in a parabolas shape. The seasonal variation of Chloris virgata community was greater than those of Leymus chinensis community and Puccinellia tenuiflora community, and "seed effect" might be the main reason. The correlation between the activity of soil catalase in different soil layers and environmental factors were analyzed. The results showed that the activity of soil catalase was decreased gradually with depth of soil layer. The activity of soil catalase was closely correlated with rainfall and air temperature, and it was affected by soil temperature, soil moisture, and their interactions. The correlation between the activity and aboveground vegetation was very significant, and the growing condition of plant communities could be reflected by the activity of soil catalase.

Catalase↗

PubMed2002

[Effect of nitric oxide on the invasive ability of human osteosarcoma through a filter membrane: an in vitro study].

OBJECTIVE: To study the effect of nitric oxide on the in vitro invasiveness of human osteosarcoma cell line (OS-732). METHODS: In vitro cultured OS-732 cell suspensions containing different concentrations of sodium nitroprusside (SNP) or PBS (control group) were used to assess the in vitro invasiveness of the tumor cells utilizing Boyden's chamber assay. The tumor cells growing across the filter membrane were counted by means of HE staining and compared between the groups. RESULTS: With the increase of SNP concentration in the cell suspension, the number of tumor cells growing across the membrane tended to decrease. With the exception of the cell suspension containing 500 micromol/L SNP that had a cell number across the membrane significantly different from those of any other groups, significant difference was not observed between any adjacent groups. Between the groups with SNP concentrations that did not come adjacent, however, significant differences were noted. CONCLUSION: Nitric oxide can depress the invasiveness of OS-732 cells across the membrane in vitro.

3T3 Cells↗

PubMed2000

Spatial variations in xylem sap flux density in the trunk of orchard-grown, mature mango trees under changing soil water conditions.

Circumferential and radial variations in xylem sap flux density in trunks of 13-year-old mango (Mangifera indica L.) trees were investigated with Granier sap flow sensor probes under limiting and non-limiting soil water conditions. Under non-limiting soil water conditions, circumferential variation was substantial, but there was no apparent relationship between sap flux density and aspect (i.e., the radial position of the sensor probes on the trunk relative to the compass). Hourly sap flux densities over 24 hours at different aspects were highly pair-wise correlated. The relationships between different aspects were constant during well-watered periods but highly variable under changing soil water conditions. Sap flux density showed marked radial variation within the trunk and a substantial flux was observed at the center of the trunk. For each selected aspect on each tree, changes in sap flux densities over time at different depths were closely correlated, so flux at a particular depth could be extrapolated as a multiple of flux from 0 to 2 cm beneath the cambium. However, depth profiles of sap flux density differed between trees and even between aspects within a tree, and also varied in an unpredictable manner as soil water conditions changed. Nevertheless, over a period of non-limiting soil water conditions, depth profiles remained relatively constant. Based on the depth profiles obtained during these periods, a method is described for calculating total sap flow in a mango tree from sap flux density at 0-2 cm beneath the cambium. Total daily sap flows obtained were consistent with water use estimated from soil water balance.

Journal Article↗

PubMed2000

Deinococcus radiodurans CatB Gene Cloning and Expression in Escherichia coli.

A 1 611 bp length complete coding sequence of the catalase (Cat) was obtained through bioimformatical analysis of the database of D.radiodurans genome, and then was amplified from D. radiodurans genomic DNA by polymerase chain reaction. The amplified gene was cloned into pKK223-3 vector and transformed into E.coli UM2, a Cat-deficient mutant. Staining of non-denaturing polyacrylamide gels for Cat activity demonstrated that pKK223-3 insert encoded a Cat that co-migrated with the CatB found in D.radiodurans cell lysates. Expression of CatB gene from D.radiodurans in E.coli UM2 restored the resistance to H(2)O(2) at low concentrations.

Journal Article↗

PubMed1999

A primary study on TRISS in a Chinese hospital.

OBJECTIVE: To investigate a revision of the Trauma and Injury Severity Score (TRISS) weight coefficients in order to overcome the inference from foreign coefficients on Chinese trauma scoring. METHODS: The data of 1 297 Chinese trauma patients were studied for trauma scoring with the Revised Trauma Score-Injury Severity Score-TRISS (RTS-ISS-TRISS) system to get a serial of new weight coefficients through analyzing a multivariation logical regression between the outcome and the injury severity. RESULTS: ISS was higher but the Age Score and probability of survival (Ps) of the death group were lower than those of the survival group. New values of RTS-ISS-Age coefficients differed from the Major Trauma Outcome Study (MTOS) ones, through which the constant b(0) decreased its negative value, and ISS weight b(2) increased its negative value, but RTS weight b(1) and age weight b(3) changed with the trauma types. MTOS's values and new values of weight coefficients were used on 1297 patients for prognosis by calculating Ps. The accuracy of new values (90.13%) was a little higher than that of MTOS's (89.5%), with a promotion in specialization but a loss in sensitivity. CONCLUSIONS: A revision of TRISS's weight coefficients is either necessary or feasible. To achieve this purpose, a Chinese trauma database with large capacity is recommended.

Journal Article↗

PubMedDate not supplied

Ultraviolet irradiation up-regulates telomerase transcription and activity in lens epithelial cells.

PURPOSE: Ultraviolet irradiation (UVR) increases telomerase activity in various cell types including skin, a sun-exposed organ. The lens is also continually exposed to UVR and we hypothesized that lenses exposed to UVR would have increased telomerase activity, with up-regulated TERT and TR, the two main components of the telomerase holoenzyme. To evaluate whether the cornea would protect lenses from such changes, whole globes, as well as isolated lenses, were exposed to UVR, and lenses were evaluated for changes in telomerase activity. METHODS: There were three parts to this project. The first part of this experiment evaluated freshly harvested normal adult canine lenses exposed to 0, 300, 600, or 1200 J/m(2) UVR, and then allowed to recover for 1, 2, 3 and 4 h. Since only 600 J/m(2) UVR increased telomerase activity, four more postexposure recovery time-points for this UVR dose were evaluated: 10 min, 30 min, 8 h and 24 h. The second part of this experiment used freshly enucleated whole canine globes exposed to 0, 50, 100, 150, 300, 600 or 1200 J/m(2) and incubated overnight; lens epithelial cells (LEC) were evaluated for telomerase activity. The third part evaluated lenses that were exposed to 0 or 600 J/m(2) UVR, and then allowed to recover for 8 and 24 h, before TERT and TR mRNA levels were measured. RESULTS: Isolated lenses exposed to 600 J/m(2) UVR had significantly higher telomerase activity than unexposed controls and other UVR doses, at all time-points except 24 h postexposure. Lenses from whole globes exposed to UVR showed a dose-dependent increase in telomerase activity except at 50 J/m(2) and 1200 J/m(2). Isolated lenses exposed to 600 J/m(2) UVR and then allowed to recover for 8 and 24 h significantly up-regulated TERT and TR mRNAs compared to unexposed control lenses. CONCLUSIONS: Telomerase activity is regulated at both the transcriptional and post-translational levels in canine LEC. Previous work in our laboratory showed dose, time, and age-dependent changes in telomerase activity in the lens. The present study showed that TERT and TR mRNA transcription was increased for up to 24 h following an acute dose of UVR. Both telomerase activity and TERT and TR mRNA levels were elevated until 24 h post-UVR exposure, TERT in combination with TR functions in proliferation-related telomerase activity, but TERT alone has an anti-apoptotic function and its up-regulation may protect LEC from the acute effects of UVR. We are continuing to evaluate the mechanisms by which telomerase is regulated in normal and cataractous LEC.

Animals↗