Biomedical subjects

Lei Dong

Publications and source records attributed to Lei Dong.

At least 91 records · Page 5Linked to original sources

PubMed2003

Antifungal diterpenoids of Pseudolarix kaempferi, and their structure-activity relationship study.

The in vitro antifungal activities of 19 structurally diversified analogues of pseudolaric acids tested against the major pathogenic fungus Candida albicans has led to the establishment of a very clear structure-activity relationship of pseudolaric acids derivatives. Pseudolaric acid A was first found to be a potent antifungal component comparable with pseudolaric acid B. Among the tested 19 diterpenoids, pseudolaric acids A2 (1), B2 (3), B3 (4) and methyl pseudolarate A2 (2) are new isolates of the root bark of Pseudolarix kaempferi, and their structures were elucidated mainly by 2D-NMR techniques and chemical methods. Compounds 12-19 were first semi-synthesized by efficient routines from pseudolaric acid B.

Animals↗

PubMed2003

Dose-response for biochemical control among high-risk prostate cancer patients after external beam radiotherapy.

INTRODUCTION: The literature on dose-response characteristics of high-risk prostate cancer has been scarce in this era, when these patients are treated with hormone therapy along with radiotherapy. In this study, we estimated the dose-response of prostate-specific antigen (PSA) control probability in high-risk prostate cancer patients treated with radiotherapy alone. METHODS AND MATERIALS: The data set contains information on 363 high-risk prostate cancer patients who were treated with external beam radiotherapy without hormonal treatment between February 1987 and September 1998. These patients have one or more of the following adverse prognostic features: digital rectal examination stage > or =cT3, PSA >20 ng/mL, and biopsy Gleason score > or =8. These patients had biopsy-proven adenocarcinoma of prostate and were staged according to the 1992 AJCC staging system that was based on digital rectal examination. The logistic model was fitted to the data at various time points after treatment, and the dose-response parameters were estimated. RESULTS: The dose required to have 50% tumor control, TCD50 (95% confidence interval), for high-risk patients is 75.5 (range: 70.7-80.2) Gy. The gamma 50 (95% confidence interval) is 1.7 (range: 0.7-2.7) around 75.5 Gy. Recursive partitioning analysis based on the null Martingale residuals identifies two subgroups within the high-risk group. The TCD50 estimates of the two subgroups (PSA < or = vs. >20 ng/mL) differ by 15 Gy at 5 years. There is a dose response in both subgroups. CONCLUSION: We recognize that this study has the usual limitations of a retrospective study that includes treatment policy change that spanned a long time frame. However, our data strongly suggest a benefit of dose escalation for all the patients in the entire high-risk group. There is a steep dose response in PSA control probability around a modern dose of 78 Gy. A 5-Gy dose increase beyond 78 Gy may improve PSA control by about 10%.

Aged↗

PubMed2003

Use of portal images and BAT ultrasonography to measure setup error and organ motion for prostate IMRT: implications for treatment margins.

PURPOSE: Traditionally, portal images have been used for verification of patient setup. More recently, direct prostate localization using ultrasound imaging has become available. The aim of this study was to use both modalities to measure daily setup error and prostate organ motion and their respective contributions to the overall uncertainty of prostate target localization. METHODS AND MATERIALS: Thirty-five patients treated for prostate cancer with intensity-modulated radiotherapy (IMRT) between February 6 and July 2, 2001 underwent daily B-mode acquisition and targeting (BAT) ultrasound localization and weekly orthogonal portal imaging. RESULTS: A total of 243 pairs of orthogonal portal films and the corresponding daily BAT images were reviewed. The mean shift +/- standard deviation in the right-left (RL), AP, and superinferior (SI) directions was 0.035 +/- 2.8 mm, -0.23 +/- 3.0 mm, and -0.013 +/- 2.0 mm, respectively, for portal films and -0.82 +/- 3.2 mm, -1.4 +/- 6.4 mm and -1.7 +/- 6.4 mm, respectively, for BAT images taken on the same day as the portal films. The mean prostate organ motion measurements were -0.89 +/- 3.3 mm (RL), -1.3 +/- 5.7 mm (AP), and -1.6 +/- 6.4 mm (SI). Without BAT localization, organ motion would have caused the clinical target volume to move outside the planning target volume margin in 23.3-41.8% of the treatments. Margins necessary to achieve complete coverage of the clinical target volume > 95% of the time without BAT would have been 5.3, 10.4 and 10.4 mm in the RL, AP, and SI dimensions, respectively. CONCLUSIONS: Prostate organ motion appears to predominate over setup error as the major component of variation in target localization. Without the use of BAT ultrasound prostate imaging, misses of the prostate can occur in a high percentage of treatments, despite patient setup verification with portal images. Relatively large planning target volume margins in the AP and SI dimensions may be necessary to overcome this.

Humans↗

PubMed2003

Patient-specific point dose measurement for IMRT monitor unit verification.

PURPOSE: To review intensity-modulated radiation therapy (IMRT) monitor unit verification in a phantom for 751 clinical cases. METHODS AND MATERIALS: A custom water-filled phantom was used to measure the integral dose with an ion chamber for patient-specific quality assurance. The Corvus IMRT planning system was used for all cases reviewed. The 751 clinical cases were classified into 9 treatment sites: central nervous system (27 cases), gastrointestinal (24 cases), genitourinary (447 cases), gynecologic (18 cases), head and neck (200 cases), hematology (12 cases), pediatric (3 cases), sarcoma (8 cases), and thoracic (12 cases). Between December 1998 and January 2002, 1591 measurements were made for these 751 IMRT quality assurance plans. RESULTS: The mean difference (MD) in percent between the measurements and the calculations was +0.37% (with the measurement being slightly higher). The standard deviation (SD) was 1.7%, and the range of error was from -4.5% to 9.5%. The MD and SD were +0.49% and 1.4% for MIMiC treatments delivered in 2-cm mode (261 cases) and -0.33% and 2.7% for those delivered in 1-cm mode (36 cases). Most treatments (420) were delivered using the step-and-shoot multileaf collimator with a 6-MV photon beam; the MD and SD were +0.31% and 1.8%, respectively. Among the 9 treatment sites, the prostate IMRT (in genitourinary site) was most consistent with the smallest SD (1.5%). There were 23 cases (3.1% of all cases) in which the measurement difference was greater than 3.5%; of those, 6 cases used the MIMiC in 1-cm mode, and 14 of the cases were from the head-and-neck treatment site. CONCLUSION: IMRT monitor unit calculations from the Corvus planning system agreed within 3.5% with the point-dose ion chamber measurement in 97% of 751 cases representing 9 different treatment sites. A good consistency was observed across sites.

Algorithms↗

PubMed2003

Experience of ultrasound-based daily prostate localization.

PURPOSE: The NOMOS (Sewickley, PA) B-mode Acquisition and Targeting System (BAT) ultrasound system provides a rapid means of correcting for interfraction prostate positional variation. In this investigation, we report our experience on the clinical issues relevant to the daily use of the BAT system and the analysis of combined setup error and organ motion for 3509 BAT alignment procedures in 147 consecutive patients treated with IMRT for prostate cancer. METHODS AND MATERIALS: After setup to external skin marks, therapists performed the BAT ultrasound alignment procedure before each IMRT treatment. In this study, a single physician (A.C.) reviewed all BAT images and classified image quality and accuracy of image alignment by the therapist. On a scale of 1-3, near-perfect image quality or alignment was given a 1, fair image quality or misalignment > or = 5 mm (likely within the PTV) was given a 2, and unacceptable image quality or misalignment >5 mm (potential to violate the PTV) was given a value of 3. The distribution of shifts made was analyzed in each dimension and for all patients. The time required to perform the BAT alignment was also assessed in 17 patients. RESULTS: Among the 3509 attempted BAT procedures, the image quality was judged to be poor or unacceptable in 5.1% (181). Of the remaining 3328 BAT images, with quality scores of 1-2, alignments were unacceptable (>5 mm misalignment as judged by the reviewing physician) in 3% (100). The mean shift in each direction, averaged over all patients, was 0.5-0.7 mm. Interfraction standard deviation (1 SD) of prostate position based on combined setup error and internal organ motion is 4.9 mm, 4.4 mm, and 2.8 mm in the anteroposterior (AP), superior-inferior (SI), and lateral (RL) dimensions, respectively. The distribution of the shifts was a near-random Gaussian-type in all three major axes, with greater variations in AP and SI directions. The percent of BAT procedures in which the shift was >5 mm was 28.6% in AP, 23% in SI, and 9% in RL directions. The average BAT procedure took extra 5 min out of a 20-min time slot in a typical eight-field IMRT treatment. CONCLUSIONS: The quality of the daily ultrasound images was deemed acceptable in 95%. Major alignment errors by therapists were only 3%. The BAT system is clinically effective and feasible in a matter of 5 min. Although the accuracy of the BAT was not addressed in this investigation, we found a significant percentage of large shifts being made from the initial alignment position.

Humans↗

PubMed2003

Intensity-modulated radiotherapy following extrapleural pneumonectomy for the treatment of malignant mesothelioma: clinical implementation.

PURPOSE: New insight into the extent of the target volume for the postoperative irradiation of malignant pleural mesothelioma as determined during surgery has indicated that standard conformal radiotherapy (IMRT) is not sufficient for curative treatment. We describe a novel technique for implementing intensity-modulated radiotherapy (IMRT) to deliver higher doses to treat the full extent of these complex target volumes. METHODS AND MATERIALS: After extrapleural pneumonectomy, 7 patients underwent simulation, treatment planning, and treatment with IMRT to the involved hemithorax and adjacent abdomen. The target volumes encompassed the entire operative bed, including the ipsilateral mediastinum, anterior pleural reflection, and ipsilateral pericardium and the insertion of the diaphragm and crura. These were extensively marked during surgery with radiopaque markers to facilitate target delineation. RESULTS: Setup uncertainty and respiratory-dependent motion were found to be small. Coverage of the planning target volume was very good, with the crus of the diaphragm the most difficult volume to irradiate. The radiation doses to normal structures were acceptable. CONCLUSION: IMRT for treatment of malignant mesothelioma after extrapleural pneumonectomy results in more potentially curative doses to large, complex target volumes with acceptable doses to normal tissues.

Humans↗

PubMed2003

Evaluation of mechanical precision and alignment uncertainties for an integrated CT/LINAC system.

A new integrated CT/LINAC combination, in which the CT scanner is inside the radiation therapy treatment room and the same patient couch is used for CT scanning and treatment (after a 180-degree couch rotation), should allow for accurate correction of interfractional setup errors. The purpose of this study was to evaluate the sources of uncertainties, and to measure the overall precision of this system. The following sources of uncertainty were identified: (1) the patient couch position on the LINAC side after a rotation, (2) the patient couch position on the CT side after a rotation, (3) the patient couch position as indicated by its digital readout, (4) the difference in couch sag between the CT and LINAC positions, (5) the precision of the CT coordinates, (6) the identification of fiducial markers from CT images, (7) the alignment of contours with structures in the CT images, and (8) the alignment with setup lasers. The largest single uncertainties (one standard deviation or 1 SD) were found in couch position on the CT side after a rotation (0.5 mm in the RL direction) and the alignment of contours with the CT images (0.4 mm in the SI direction). All other sources of uncertainty are less than 0.3 mm (1 SD). The overall precision of two setup protocols was investigated in a controlled phantom study. A protocol that relies heavily on the mechanical integrity of the system, and assumes a fixed relationship between the LINAC isocenter and the CT images, gave a predicted precision (1 SD) of 0.6, 0.7, and 0.6 mm in the SI, RL and AP directions, respectively. The second protocol reduces reliance on the mechanical precision of the total system, particularly the patient couch, by using radio-opaque fiducial markers to transfer the isocenter information from the LINAC side to the CT images. This protocol gave a slightly improved predicted precision of 0.5, 0.4, and 0.4 mm in the SI, RL and AP directions, respectively. The distribution of phantom position after CT-based correction confirmed these results. Knowledge of the individual sources of uncertainty will allow alternative setup protocols to be evaluated in the future without the need for significant additional measurements.

Artifacts↗

PubMed2003

Automatic registration of the prostate for computed-tomography-guided radiotherapy.

The recent development of integrated computed tomography (CT)/linear accelerator (LINAC) combinations, where the CT scanner and the LINAC use the same patient couch, and of kilovoltage cone-beam CT systems attached to the LINAC gantry, means that suitable hardware is now available for CT-guided localization of the prostate. Clinical implementation is, however, currently impeded by the lack of robust and accurate software tools to compare the position of the prostate in the CT images used for the treatment plan with its position in the daily CT images. Manual registration of the planning CT images with the daily CT images can be slow and can introduce significant inter-user variations. We have developed an automatic registration technique that is not adversely influenced by changes in prostate shape, size or orientation, presence of rectal gas, or bladder filling. The cost function used in the registration is the mean absolute difference in CT numbers voxel-by-voxel between the daily CT image and the planning CT image for a volume extracted from the planning CT images using the original physician-drawn gross tumor volume contours. To enhance soft tissue contrast in the prostate region and to reduce the impact of rectal gas calcifications and bone on the registration, voxels with CT numbers that represent gas or bone are filtered out from the calculation. The results of the automatic registration agreed with the mean results of seven human observers, with standard deviations of 0.5 mm, 0.5 mm, and 1.0 mm in the left/right (RL), anterior/posterior (AP), and superior/inferior (SI) directions, respectively, for a patient that was relatively easy to localize. Agreement (one standard deviation) for a patient that was difficult to localize was 0.6 mm, 1.4 mm, and 1.9 mm in the RL, AP, and SI directions, respectively. These results are better than the interuser uncertainties reported for a manual alignment technique and are close to the reported intrauser uncertainties. The results are independent of the shape of contours in the original treatment plan, reducing the impact of interobserver variations in contouring the prostate. The algorithm is fast and reliable, allowing the entire CT localization process to take place in 5-9 minutes. In 120 CT image sets from seven patients, the failure rate was found to be less than 1%. The use of this algorithm will facilitate the clinical implementation of CT-guided localization of the prostate.

Algorithms↗

PubMed2003

Effects of neurotrophins on gastrointestinal myoelectric activities of rats.

AIM: To observe the effects of mouse nerve growth factor (NGF), rat recombinant brain derived neurotrophic factor (rm-BDNF) and recombinant human neurotrophin-3 (rh-NT-3) on the gastrointestinal motility and the migrating myoelectric complex (MMC) in rat. METHODS: A randomized, double-blinded, placebo-controlled experiment was performed. 5-7 days after we chronically implanted four or five bipolar silver electrodes on the stomach, duodenum, jejunum and colon, 21 experimental rats were coded and divided into 3 groups and injected NGF, rm-BDNF, rh-NT-3 or placebo respectively via tail vein at a dose of 20 microg x kg(-1). The gastrointestinal myoelectrical activity was recorded 2 hours before and after the test substance infusions in these consciously fasting rats. RESULTS: The neurotrophins-induced pattern of activity was characterized by enhanced spiking activity of different amplitudes at all recording sites, especially in the colon. In the gastric antrum and intestine, only rh-NT-3 had increased effects on the demographic characteristics of electrical activities (P<0.05), but did not affect the intervals of MMCs. In the colon, all the three kinds of neurotrophins could significantly increase the frequency, amplitude and duration levels of spike bursts, and also rh-NT-3 could prolong the intervals of MMC in the transverse colon (25+/-11 min vs 19+/-6 min, P<0.05). In the distal colon rh-NT-3 could evoke phase III-like activity and disrupt the MMC pattern, which was replaced by a continuously long spike bursts (LSB) and irregular spike activity (ISA) for 48+/-6 min. CONCLUSION: Exogenous neurotrophic factors can stimulate gut myoelectric activities in rats.

Animals↗

PubMed2003

Portal hypertensive gastropathy and its interrelated factors.

OBJECTIVE: To investigate the influences of helicobacter pylori (Hp) infection, liver function, gastroesophageal varicosity, esophageal varicosity ligation (EVL), and esophageal varicosity sclerotherapy (EVS) on patients with portal hypertensive gastropathy (PHG). METHODS: Fourty-seven patients with liver cirrhosis included 34 patients with PHG and 13 patients without PHG. Liver function, Hp infection, and gastroesophageal varicosity were investigated clinically in all patients, and gastroscopy was made again in patients with EVL 1-2 months after operation to observe the changes of PHG. RESULTS: The rate of Hp infection was lower in patients with liver cirrhosis than in controls. There was no relationship between Hp infection and PHG. The patients with gastroesophageal varicosity had a high incidence of PHG. CONCLUSIONS: Despite no relationship between Hp infection and PHG, liver dysfunction can affect and promote PHG. Gastroesophageal varicosity may be closely related to PHG, but their degrees are not related. PHG can be caused or promoted by EVL.

Adolescent↗

PubMed2003

[Comparison of imaging modalities for image-guided radiation therapy (IGRT)].

The use of a new integrated CT/LINAC combination, in which the CT scanner is inside the treatment room, and the same patient couch is used for CT scanning and treatment, should allow for accurate and precise correction of interfractional set-up errors. Comparison of intentional shifts in phantom position as detected by the CT system with shifts detected by an ultrasound localization device commonly used for prostate localization, and by an electronic portal imaging device, showed the standard deviation of set-up uncertainties to be within 1 mm in all directions for each modality. The agreement between the modalities was within 2.6 mm, 1.6 mm and 1.7 mm in the superior-inferior (SI), anterior-posterior (AP) and right-left (RL) directions, respectively. All these modalities are, therefore, suitable for image-guided radiation therapy applications. The choice of modality can be made based of factors such as anatomical site, inter-user variations, and patient set-up.

Humans↗

PubMed2003

[Clinical study of 102 cases of abdominal-anus resection with telescopic anastomosis of colon rectal mucosa for lower segment of rectal cancer].

OBJECTIVE: To investigate the reliability and feasibility of abdominal-anus resection with preservation of anal sphincter by telescopic anastomisis of colon rectal mucosa for middle-lower segment of rectal cancer. METHODS: A retrospective analysis was made for abdominal-anus resection with telescopic anastomosis of colon rectal mucosa in 102 cases of middle-lower segment of rectal cancer. RESULTS: No anastomotic fistula and anastomotic stenosis occurred in the 102 cases. The increased defecation was found during early stage of postoperation, about 6-12 times per day. But this was easily controlled by antidiarrheal drugs. Twelve to 18 weeks later, defecation returned to normal. Follow-up was performed in 91 patients, and the follow-up rate was 89.2%. Mean follow-up period was 4.7 years. Local recurrence rate of the carcinoma was 5.4% (5/91), and hepatic metastasis rate was 13.1% (12/91). Three-year survival rate of postoperation was 86.9% (60/80), and five-year survival rate was 70.7% (29/41). CONCLUSIONS: With telescopic anastomosis of colon rectal mucosa, colon stoma can be avoided, and anastomotic fistula can be prevented. The operation is safety and effective in preservation of anal sphincter for rectal cancer therapy.

Adult↗

PubMed2002

Late rectal toxicity: dose-volume effects of conformal radiotherapy for prostate cancer.

PURPOSE: To identify dosimetric, anatomic, and clinical factors that correlate with late rectal toxicity after three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer. METHODS AND MATERIALS: We retrospectively analyzed the dose-volume histograms and clinical records of 163 Stage T1b-T3c prostate cancer patients treated between 1992 and 1999 with 3D-CRT, to a total isocenter dose of 74-78 Gy at The University of Texas M. D. Anderson Cancer Center. The median follow-up was 62 months (range 24-102). All late rectal complications were scored using modified Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force criteria. The 6-year toxicity rate was assessed using Kaplan-Meier analysis and the log-rank test. A univariate proportional hazards regression model was used to test the correlation between Grade 2 or higher toxicity and the dosimetric, anatomic, and clinical factors. In a multivariate regression model, clinical factors were added to the dosimetric and anatomic variables to determine whether they significantly altered the risk of developing late toxicity. RESULTS: At 6 years, the rate of developing Grade 2 or higher late rectal toxicity was 25%. A significant volume effect was observed at rectal doses of 60, 70, 75.6, and 78 Gy, and the risk of developing rectal complications increased exponentially as greater volumes were irradiated. Although the percentage of rectal volume treated correlated significantly with the incidence of rectal complications at all dose levels (p <0.0001 for all comparisons), the absolute rectal volume appeared to be a factor only at the higher doses of 70, 75.6, and 78 Gy (p = 0.0514, 0.0016, and 0.0021, respectively). The following variables also correlated with toxicity on the univariate analysis: maximal dose to the clinical target volume, maximal dose to rectum, maximal dose to the rectum as a percentage of the prescribed dose, and maximal dose delivered to 10 cm(3) of the rectum. Of the clinical variables tested, only a history of hemorrhoids correlated with rectal toxicity (p = 0.003). Multivariate analysis showed that the addition of hemorrhoids increased the risk of toxicity for each dosimetric variable found to be significant on univariate analysis (p <0.05 for all comparisons). CONCLUSION: Dose-volume histogram analyses clearly indicated a volume effect on the probability of developing late rectal complications. Therefore, dose escalation may be safely achieved by adherence to dose-volume histogram constraints during treatment planning and organ localization at the time of treatment to ensure consistent patient setup.

Aged↗

PubMed2002

Intrafraction prostate motion during IMRT for prostate cancer.

PURPOSE: Although the interfraction motion of the prostate has been previously studied through the use of fiducial markers, CT scans, and ultrasound-based systems, intrafraction motion is not well documented. In this report, the B-mode, Acquisition, and Targeting (BAT) ultrasound system was used to measure intrafraction prostate motion during 200 intensity-modulated radiotherapy (IMRT) sessions for prostate cancer. METHODS AND MATERIALS: Twenty men receiving treatment with IMRT for clinically localized prostate cancer were selected for the study. Pre- and posttreatment BAT ultrasound alignment images were collected immediately before and after IMRT on 10 treatment days for a total of 400 BAT alignment procedures. Any ultrasound shifts of the prostate borders in relation to the planning CT scan were recorded in 3 dimensions: right-left (RL), anteroposterior (AP), and superior-inferior (SI). Every ultrasound procedure was evaluated for image quality and alignment according to a 3-point grading scale. RESULTS: All the BAT images were judged to be of acceptable quality and alignment. The dominant directions of intrafraction prostate motion were anteriorly and superiorly. The mean magnitude of shifts (+/-SD) was 0.01 +/- 0.4 mm, 0.2 +/- 1.3 mm, and 0.1 +/- 1.0 mm in the left, anterior, and superior directions, respectively. The maximal range of motion occurred in the AP dimension, from 6.8 mm anteriorly to 4.6 mm posteriorly. The percentage of treatments during which prostate motion was judged to be 5 mm. The extent of intrafraction motion was much smaller than that of interfraction motion. Linear regression analysis showed very little correlation between the two types of motion (r = 0.014, 0.029, and 0.191, respectively) in the RL, AP, and SI directions. CONCLUSION: Using an ultrasound-based system, intrafraction prostate motion occurred predominantly in the anterior and superior directions, but was clinically insignificant. Intrafraction motion was much smaller than interfraction motion, and the two types of movement did not correlate.

Humans↗

PubMed2002

Rapid radiographic film calibration for IMRT verification using automated MLC fields.

A method for measuring a film sensitometric curve using a single sheet of film exposed with a two field step-and-shoot MLC treatment was developed and tested with Kodak XV2 and EDR2 films. With this technique a film sensitometric curve can be completed in only 10 minutes, making it practical to generate new film calibrations daily. This method is applicable to film calibrations for all purposes, but is particularly useful in IMRT treatment verification due to the method's use of small fields. This method agrees with the traditional large-field multifilm calibration within 0.5% and will produce sensitometric curves with errors less than 1% throughout the dose range, including uncertainties in dose delivery, film response, and optical density measurements. OD values for XV2 and EDR2 films were consistent in the middle of exposure areas at high depths, but the XV2 film penumbra regions showed large amounts of over-response as the calibration depth increased. If XV2 film is used for IMRT treatment verification, it is necessary to reduce the fluence of low energy photons in areas around the film by using thin lead shields. EDR2 film was shown to have minimal energy dependence, as it accurately represented penumbra areas and yielded identical sensitometric curves generated with 6 and 18 MV photons. However, its darker tint may make it more sensitive to scanning laser film digitizers' horizontal nonuniformities. This single film method proved to be superior to the traditional calibration method and allows fast daily calibrations of films for highly accurate IMRT delivery verifications.

Calibration↗

PubMed2002

The role of KDR in the interactions between human gastric carcinoma cell and vascular endothelial cell.

AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and the role of KDR in these interactions. METHODS: Antisense oligodexynucleotide(ASODN) specific to KDR gene was devised and added to the culture medium of HGCC and HVEC. After the action of ASODN, the proliferation of two cells was measured by MTT method. The role of KDR in regulating the proliferation of two kinds of cells was known through observing the effect of ASODN on them. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added acting on the other kind of cell, then the cell proliferation was measured by MTT. After the action of ASODN or CM, the cellular expression of KDR gene was detected with in situ hybridization (ISH) for mRNA level and with immunohistochemical staining for protein level. ABC -ELISA was used to detect hVEGF in the CMs of two cells. RESULTS: KDR ASODN could specifically inhibit the proliferation of HGCC and HVEC significantly. The growth inhibitory rate amounted to 55.35 % and 54.83 %, respectively (P<0.01). HGCC and HVEC could secret a certain level of hVEGF(92.06+/-1.69 ng/L, 77.70+/-8.04 ng/L). The CM of HGCC could significantly stimulate the growth(2.70+/-0.01 times) and KDR gene expression of HVEC(P<0.01) while the CM of HVEC could significantly inhibit the growth(52.97+/-0.01 %) and KDR gene expression of HGCC (P<0.01). CONCLUSION: KDR plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. KDR is involved in the interactions between them.

Cell Communication↗

PubMed2002

Expression of sphingosine kinase gene in the interactions between human gastric carcinoma cell and vascular endothelial cell.

AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and if the expression of sphingosine kinase(SPK) gene was involved in these interactions. METHODS: The specific inhibitor to SPK, dimethyl sphingosine (DMS), was added acting on HGCC and HVEC, then the cell proliferation was measured by MTT. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added to the other kind of cell, and the cell proliferation was measured by MTT. After the action of CM, the cellular expression of SPK gene in mRNA level was detected with in situ hybridization(ISH). RESULTS: DMS could almost completely inhibit the proliferation of HGCC and HVEC. The growth inhibitory rates could amount to 97.21 %, 83.42 %, respectively (P<0.01). The CM of HGCC could stimulate the growth of HVEC (2.70+/-0.01, P<0.01) while the CM of HVEC could inhibit the growth of HGCC (52.97+/-0.01 %, P<0.01). There was no significant change in the mRNA level of SPK gene in one kind of cell after the action of the CM of the other kind of cell. CONCLUSION: SPK plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. The expression of SPK gene is not involved in the interactions.

Cell Communication↗

PubMed2002

Estrogen reduces CCL4- induced liver fibrosis in rats.

AIM: Chronic liver diseases, such as fibrosis or cirrhosis, are more common in men than in women. This gender difference may be related to the effects of sex hormones on the liver. The aim of the present work was to investigate the effects of estrogen on CCL(4)-induced fibrosis of the liver in rats. METHODS: Liver fibrosis was induced in male, female and ovariectomized rats by CCL(4) administration. All the groups were treated with estradiol(1 mg/kg) twice weekly. And tamoxifen was given to male fibrosis model. At the end of 8 weeks, all the rats were killed to study serum indicators and the livers. RESULTS: Estradiol treatment reduced aspartate aminotransferase(AST), alanine aminotransferase (ALT), hyaluronic acid(HA) and type IV collagen(CIV) in sera, suppressed hepatic collagen content, decreased the areas of hepatic stellate cells (HSC) positive for alpha-smooth muscle actin (alpha-SMA), and lowered the synthesis of hepatic type I collagen significantly in both sexes and ovariectomy fibrotic rats induced by CCL(4) administration. Whereas, tamoxifen had the opposite effect. The fibrotic response of the female liver to CCL(4) treatment was significantly weaker than that of male liver. CONCLUSION: Estradiol reduces CCL(4)-induced hepatic fibrosis in rats. The antifibrogenic role of estrogen in the liver may be one reason for the sex associated differences in the progression from hepatic fibrosis to cirrhosis.

Actins↗