Biomedical subjects

L Chen

Publications and source records attributed to L Chen.

At least 451 records · Page 25Linked to original sources

PubMed2000

[The value of nuclide myocardial scintigraphy for the clinical of acute viral myocarditis].

OBJECTIVE: To investigate the significance of nuclid myocardial scintigraphy (ECT) as a clinical method for guiding the diagnosis, therapy and prognosis of a cute viral myocarditis. METHODS: 48 patients with acute viral myocarditis were divided into two groups, 21 patients with ECT showing diffuse myocardial perfusion defect constituted a positive group and the remaining 27 with normal ECT a negative group. The relationship between the clinical data and treatment effect in the two groups were analyzed. RESULTS: In the positive group, CK-MB in 57.14% of the patients was higher than normal and 71.43% of the patients had ventricular premature beats (VPB) and atrial premature beats (APB). The average number of VPB per 24 hour was (4228 +/- 1506) beats. In the negative group, the values of the above items were 33.33%, 44.44% and (2268 +/- 924) beats. The difference between the two groups was statistically significant (all of P < 0.01). After treatment of acute viral myocarditis, ECT of all the patients in the positive group returned to normal completely 85.71% of the patients with premature beats recovered from the arrhythmia. 38.10% of the patients with premature beats had arrhythmia again during a follow-up of 4 years. However, in the negative group, only 59.26% of the patients with premature beats recovered from the arrhythmia and 66.67% had arrhythmia again during the 4 years. The therapeutic effect between the two groups was also statistically different (all of P < 0.01). CONCLUSION: Up to now, there has been no unified diagnostic standard for acute viral myocarditis, so ECT may be an exact and reliable diagnostic method for acute viral myocarditis. It may help to avoid error in diagnosis, waste in health resources and side effects of the medications.

Acute Disease↗

PubMed2000

[Reversal of multidrug resistance in lung adenocarcinoma-resistant cell line A549/R by mdr1 antisense oligodeoxynucleotides in vitro].

OBJECTIVE: To investigate the possibility of reversion of multidrug resistance (MDR) in lung adenocarcinoma-resistant cell line A549/R by mdr1 antisense oligodeoxynucleotide. METHODS: A 15-mer phosphorothioate antisense oligodeoxynucleotide (ATCCATCCCGACCTC), complementary to -9 approximately + 6 in mdr1 cDNA sequence, was synthesized. Meanwhile, sense sequence (GAGGTCGGGATGGAT) was taken as control. Both antisense and sense oligodeoxynucleotides were transduced to A549/R cell line by lipofectin. The mdr1 mRNA, expression of Pgp, cellular rhodamine accumulation and sensitivity to daunorubicin were detected in antisense and sense oligodeoxynucleotides treated cells, using RT-PCR, flow cytometry, rhodamine test and MTT method. RESULTS: Treatment with antisense oligodeoxynucleotide in A549/R cells led to a decrease in mdr1 mRNA and Pgp expression, an increase in rhodamine cellular accumulation, and a 20-fold increase of sensitivity to doxorubicin compared with those treated with sense oligodeoxynucleotide or control cells. CONCLUSION: The mdr1 antisense oligodeoxynucleotide possesses an effect of reversing MDR in lung adenocarcinoma-resistant cell A549/R by inhibiting mdr1 transcription and Pgp expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

[Persistence of hepatitis C virus type II in patient's peripheral blood B lymphocytes transformed by Epstein-Barr virus].

OBJECTIVE: To study the persistence and replication of hepatitis C virus (HCV)-RNA in human peripheral blood B cells transformed by Epstein-Barr virus (EBV) and cultured in vitro. METHODS: EBV was used for infecting B lymphocytes from one hepatitis C patient with HCV positive in the peripheral blood mononuclear cells (PBMC) and transforming them into lymphoblasts capable of being propagated indefinitely. Then, HCV RNA of the cultured cells and supernatants was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) every one month. HCV gene was typed by enzyme separating method. Electron microscopy and immunoelectron microscopy were employed to locate HCV in the cells and observe the character of its configuration. RESULTS: HCV positive-strand RNA was detected in the cultured cells for 1 year. Interestingly, the HCV positive-strand RNA was identified in supernatants and the negative-strand RNA was also observed in the cultured cells intermittently. HCV gene was type II. Electron microscopy observed HCV spherical virus-like particles with a diameter of approximately 45 nm to 70 nm, individual particles 110 nm, in the LCL cytoplasmic vesicles. CONCLUSION: HCV may exist in the cultured cell line for a longer period and reproduce in and secrete out of them. HCV locates mainly in the cytoplasm. The cell line might be useful in analyzing the mechanisms of HCV persistence in PBMC.

5' Untranslated Regions↗

PubMed2000

[The establishment of the model for differential diagnosis of borderline cases with anterior crossbite using fuzzy set theory].

OBJECTIVE: To introduce the fuzzy set theory to orthodontics by using the diagnostic information drawn out from the diagnosed cases to solve the problem of borderline- case diagnosis. METHOD: Lateral cephalometric radiographs of 107 anterior crossbite patients in early permanent dentition were traced, measured, and 31 variables calculated. Diagnosis was made by experienced specialists and the cases were divided into three groups: dental anterior crossbite (52 cases), borderline cases (22 cases) and skeletal anterior crossbite (33 cases). Among 85 cases with accurate diagnosis we selected 70 cases to establish 6-factor model using stepwise discriminant analysis. This afforded 100 percent correct respective check and the predictive diagnosis of the other 15 cases showed that its correction rate was 93.3 percent which proved that most useful information was included. Then the contributions of the six variables were calculated and we established two sets: skeletal anterior crossbite set and dental anterior crossbite set with skeletal and dental means to be their thresholds. For each case the individual measurements of the six variables were standardized and afterwards transferred into constituent ratio and at the same time their degrees of membership of these two sets were calculated according to the distance between its location and the two thresholds. Using this fuzzy model we got the individual scores of the two sets. The diagnosis of the patient was coincident with the set of higher scores. This model was testified by 85 cases with accurate diagnosis and its correction was absolute. RESULT: 22 borderline cases were diagnosed by this model. CONCLUSION: The two-set difference were far less than that of the cases with accurate diagnosis which prove the model was reasonable.

Dentition, Permanent↗

PubMed2000

[Magnetic resonance angiography in assessing changes of pre-and post-disconnective portal system in patients with portal hypertension].

OBJECTIVE: To evaluate the role of magnetic resonance angiography (MRA) in assessing the portal system changes in patients with portal hypertension after pericardial devascularization and splenectomy. METHODS: The portal diameter, blood velocity and flow, collateral circulation, variceal vein and other portal parameters of 15 patients with portal hypertension receiving pericardial devascularization and splenectomy and splenectomy were comparatively evaluated with Siemens 1.5 T MRI 1 week before operation and 2 weeks after operation. RESULTS: The portal diameters decreased after operation, with the disappearance or alleviation of esophageal and fundal variceal veins. In 15 patients, 9 showed. The blood velocity and flow of the portal veins were lower postoperatively. than those preoperatively; In 15 patients, 9 showed increased gastric imaging intensity after operation. CONCLUSIONS: MRA can provide high quality and concrete 3-dimensional information about the portal system and hemodynamics of portal hypertensive patients. It is an important non-invasive way in evaluating the effects of operations and long-term follow-up. Postoperative gastric venous congestion possibly causes increased portal hypertensive gastropathy after disconnection.

Blood Flow Velocity↗

PubMed2000

[Endoluminal stent-graft repair of aortic aneurysms].

OBJECTIVE: To study the clinical value of the treatment of aortic aneurysms with endovascular stent-graft prosthesis. METHODS: After a unilateral surgical arteriotomy, Talent, Vanguard and Chinese stent-graft were advanced through the femoral arteries and placed in the proper position of the aneurysm sac under X-ray fluoroscopic guidance. RESULTS: Four patients with descending aneurysm, 1 patient with abdominal aortic aneurysm (AAA) involving the renal artery, superior mesenteric artery and celiac artery, and 1 patient with right common iliac artery aneurysm received straight stent-grafts. Five patients with infrarenal AAA received bifurcated stent-grafts. CT and MRA were performed during a follow-up of 3 - 19 months. Aortic aneurysms were completely excluded from the circulation. Five patients prolonged fever was noted and 1 patient was found to have a leakage 3 months later, and hemiplegia in 1 after procedure. CONCLUSIONS: Endovascular treatment of aortic aneurysm is technically feasible and can effectively exclude aortic aneurysms from the circulation. Endoluminal repair may serve as an interventional strategy to treat aneurysm, especially in patients at high surgical risk, but long term effect needs further study.

Adult↗

PubMed2000

Expression of alpha1 adrenoceptor subtypes mRNA in hepatic tissues of cirrhotic patients with portal hypertension.

OBJECTIVE: To investigate the expression of mRNA of alpha(1) adrenoceptor in the hepatic tissues of cirrhotic patients with portal hypertension. METHODS: Semi-quantitative reverse transcription and polymerase chain reaction (RT-PCR) was used in 12 hepatitis virus B-related cirrhotic patients with portal hypertension and 15 controls who had no history of portal hypertension. In these patients, routine liver biopsy was performed. Special alpha(1) adrenoceptor subtype product and internal standard GAPDH product were both amplified by RT-PCR. The ratio of their integral optical density (IOD) was calculated as the relative expression of the alpha(1) adrenoceptor subtypes. RESULTS: The relative mRNA expression of alpha(1a) adrenoceptor subtype in the hepatic tissues was significantly lower in the cirrhotic patients (0.26 +/- 0.12) than in the controls (0.86 +/- 0.38, P < 0.01). The relative mRNA expression of alpha(1b) adrenoceptor subtype in the hepatic tissues was also significantly lower in the cirrhotic patients (0.03 +/- 0.01) than in the controls (0.23 +/- 0.10, P < 0.01). Neither the cirrhotic patients nor the controls showed alpha(1d) adrenoceptor subtype in the hepatic tissues. The relative mRNA expression of alpha(1a) adrenoceptor subtype was significantly higher than that of alpha(1b) adrenoceptor subtype in the hepatic tissues of both cirrhotic patients and controls (P < 0.01). CONCLUSIONS: The alpha(1a) adrenoceptor mRNA expression predominates in both normal and cirrhotic hepatic tissues. The expression of alpha(1b) adrenoceptor is less marked and there is no expression of alpha(1d) adrenoceptor. The decreased expression of mRNA of alpha(1a) and alpha(1b) adrenoceptor may underlie the decrease of alpha(1) adrenoceptor proteins often seen in the hepatic tissues of cirrhotic patients, and may play an important role in the pathogenesis and maintenance of portal hypertension.

Adult↗

PubMed2000

[A clinical study on fresh amniotic membrane transplantation for treatment of severe ocular surface disorders at acute inflammatory and cicatricial stage].

OBJECTIVE: To investigate the safety and evaluate the effect of fresh amniotic membrane transplantation to reconstruct the ocular surface with severe inflammation and scarring. METHOD: Amniotic membrane transplantation (38 cases, 46 eyes), or combined with either limbal transplantation (9 cases, 9 eyes) or lamellar keratoplasty (8 cases, 8 eyes) was performed on ocular surface burns (5 cases, 6 eyes), recurrent Mooren's ulcer (8 cases, 8 eyes) and severe symblepharon (38 cases, 46 eyes). All the patients were followed-up for 6 - 18 months (mean, 11 months). Impression cytology was examined in 21 eyes with normal tear secretion post-operatively. RESULTS: No acute rejection was observed after fresh amniotic membrane transplantation. No progressive melt and perforation were seen in five out of six eyes with burns in reconstructed ocular surfaces. Neovascularization, pseudopterygium and iris atrophy were not found during the follow-up. Visual acuity was improved in various degrees. Corneal ulceration was not noted in 8 cases (8 eyes) with frequently recurrent Mooren's ulcer. Ocular surface reconstruction was successful in 46 of 49 eyes with severe symblepharon. Symblepharon occurred in the remaining three eyes but much less than pre-transplantation in degree. Amniotic epithelia have been examined in about three months on the transplanted eyes with normal tear secretion. CONCLUSION: Fresh amniotic membrane can be used as a graft to reconstruct ocular surface. Such transplantation can effectively reduce neovascularization, fibrosis and inflammation. Our data indicated that complete removal of pathological tissues and perfect fixation of amniotic membrane graft are crucial steps in the reconstruction of ocular surface.

Acute Disease↗

PubMed2000

[Effects of fluoride on the expression of c-fos and c-jun genes and cell proliferation of rat osteoblasts].

OBJECTIVE: To investigate the effects of sodium fluoride (NaF) on the expression of c-Fos and c-Jun genes and osteoblast cell proliferation of rat osteoblasts. METHODS: Osteoblastic cells were isolated from baby rat calvaria, and cultured in the presence of different doses of NaF (10(-5) mol/L, 10(-4) mol/L, and 10(-3) mol/L). Cell proliferation was measured by the MTT method, and c-Fos and c-Jun expression was detected by the immunohistochemistry combined with image analysis compute system. RESULTS RESULTS: from the MTT assay showed that NaF increased the proliferation of rat osteoblast and induced the expression of c-Fos and c-Jun genes. The increases of c-Fos and c-Jun expression by the 3 different doses of NaF were 5.4%, 15.4% and 42.3% for the c-Fos gene and 12.1%, 14.4% and 38.6% for c-Jun gene respectively (P < 0.05 and P < 0.01). CONCLUSION: NaF increased rat osteoblastic cell proliferation and the expression of genes involved in cell proliferation.

Animals↗

PubMed2000

[The relationship between vascular endothelial growth factor, microvascular density, lymph node metastasis and prognosis of breast carcinoma].

OBJECTIVE: To investigate the relationship between vascular endothelial growth factor (VEGF) microvascular density (MVD), lymph node metastasis and prognosis of breast carcinoma (BC). METHODS: VEGF protein expression and MVD in 92 cases of BC and VEGF mRNA expression in part of the cases were studied by immunohistochemistry methods and reverse-transcription polymerase chain reaction (RT-PCR) technique. RESULTS: VEGF mRNA expression in BC tumor tissues were higher than those in adjacent normal tissues. Increment of both VEGF(121) and VEGF(165) showed significant difference (P < 0.05 approximately 0.01). In addition, VEGF(145) expression was also observed in BC. There was a close positive correlation between VEGF and MVD (r = 0.702, P < 0.01). VEGF protein expression and MVD correlated significantly with lymph node metastasis and tumor relapse (P < 0.05 approximately 0.01). The time period of relapse-free-survival (RFS) in the patient group with high VEGF expression and MVD was significantly lower than RFS in the group with low VEGF expression and MVD (P < 0.01). CONCLUSION: VEGF is highly related to angiogenesis of BC. The increase of VEGF and MVD may promote lymph node metastasis and relapse of BC. VEGF and MVD may have prognostic value in RFS of BC patients.

Adult↗

PubMed2000

[Distribution of minimal residual leukemia in Brown Norway rats express LacZ gene].

OBJECTIVE: To investigate the distribution of minimal residual leukemia (MRL) in vivo. METHODS: The MRL model in BN rat was established by using LT12nl leukemia cell line carrying LacZ gene. The marker gene (LacZ) was detected by using reverse transcriptase polymerase chain reaction (RT-PCR) and nested PCR, X-gal staining, and cytomorphological and pathological examination. RESULTS: PCR assays showed positive result in humerus at day 4, femur at day 6, and spleen at day 9 after CTX treatment. The peak positive signal in humerus was stronger at day 9. X-gal staining showed negative in spleen at day 9. PCR showed negative results in peripheral blood and liver. CONCLUSION: PCR can be used as an effective tool to investigate the distribution pattern in experimental MRL.

Animals↗

PubMed2000

[The mechanisms of inhibitory effect of bufalin on human leukemia cells].

OBJECTIVE: To study the mechanism of bufalin on human leukemia cell inhibition. METHODS: HL-60 cells were treated with bufalin at different concentrations. The growth inhibition was analysed by MTT assay, cell apoptosis by light microscopy, transmission electron microscopy, flow cytometry, TUNEL labeling method and agarose gel electrophoresis. RESULTS: (1) Treatment of HL-60 cells with bufalin remarkably inhibited the cell growth, the IC(50) value of bufalin for HL-60 cells was 0.025 micromol/L. (2) Apoptosis of HL-60 cells could be efficiently induced by bufalin at concentration of 0.010 micromol/L or higher. (3) Bufalin induced apoptosis of HL-60 cells in a dose- and time-dependent manner. (4) With G(1) phase cells decreasing, S phase cells increased, and then apoptotic cells increased with a diminution of S phase cells. (5) Bufalin-induced apoptosis of HL-60 cells was inhibited by ZnCl(2), an inhibitor of endonuclease, but not by cycloheximide, an inhibitor of protein synthesis. CONCLUSION: Bufalin could efficiently induce apoptosis of HL-60 cells, especially the S phase cells.

Apoptosis↗

PubMed2000

[Influence of hepatic stimulator substance on p21(ras) expression in human hepatic carcinoma cells BEL-7402].

The hepatic stimulator substance (HSS) was partially purified from schedule-lighted weanling rat livers. The effects of HSS on p21(ras) expression of human hepatic carcinoma cell BEL-7402 were examined. The results showed: (1) HSS was capable of promoting the proliferation of the cells, and its molecular weight was 14 20 kD; (2) the p21(ras) expression was increased under HSS effect time-dependently, and the effect of HSS appeared synergistic with EGF; (3) the p21(ras) expression induced by HSS manifested a dose-dependent manner, and the saturation effect of HSS occurred at the concentration of 100 microgram/ml. Considering together with our previous report about HSS regulation on EGF receptor, these results strongly suggest that the proliferatory effect of HSS on hepatic carcinoma cells is presumedly related with EGF receptor-mediated signal transduction.

Animals↗

PubMed2000

[Studies on senility retarding effect of qiangshengye liquid].

OBJECTIVE: To observe the effect of Qiangshengye liquid on senility retarding in rats. METHODS: The liquid was orally administrated to rats at doses of 3.3 g.kg-1 and 6.6 g.kg-1, and after Twenty-one days the activity of superoxide dismutase (SOD) in red blood cells and lipid peroxide(LPO) in plasma and in liver were examined respectively by spectrophotometry. Fluorescence polarization was used to evaluate the fluidity of erythrocyte membrane. In addition the anti-fatigue effect of the liquid in mice was detected. RESULTS: The liquid can significantly increase the activity of SOD(P < 0.05) in red blood cells and decrease the contents of LPO in plasma (P < 0.05) and in liver(P < 0.01). The fluidity of erythrocyte membrane was also improved (P < 0.05). CONCLUSION: Qiangshengye liquid can antagonize lipid peroxidation and therefore may be used for anti-fatigue and senility retarding purposes.

Aging↗

PubMed2000

[Extraction and separation of antitumor components from Ganoderma lucidum (Leyss. ex Fr.) Karst].

OBJECTIVE: To examine the variation of alcohol extraction rates of Ganoderma lucidum spores with different rates of wall-wrack, and analyze the antitumor components of alcohol extract by chromatography. METHOD: The G. lucidum spores were soaked and extracted with absolute alcohol. The alcohol extract was chromatographed on a silica gel column and HPLC in proper order, and the antitumor activity of every eluted fraction was represented by its cytotoxicity towards Hela cells. RESULT: Extraction rates 5%, 25% and 33% corresponded to wall-wrack rates 0%, 60%-80% and 99% respectively. The alcohol extract from spores with the highest wall-wrack rate was chromatographed on a silica gel column, eluting successfully with CHCl3, EtOAc and CH3OH in order. The CHCl3 fraction had not any antitumor activity, while this activity of CH3OH fraction was 34 times greater than that of EtOAc fraction. HPLC analysis found out that two mixtures(II1 and II3) possess significant antitumor activity in vitro. CONCLUSION: The weight of alcohol extract from spores with wall-wrack was far greater than that of spores without. The antitumor components of G. lucidum spores could be analyzed with methanol-water on a reverse HPLC.

Antineoplastic Agents, Phytogenic↗

PubMed2000

[Expressional change of brain-derived neurotrophic factor in adult cat spared DRG].

UNLABELLED: This investigation was aimed to search the expressional change of BDNF in the normal and spared L6DRG. The L6DRGs from 20 adult male cats (5 normal cats, 15 unilateral L6 spared roots cats allowed to survive 3 days, 6 days and 12 days respectively) were embedded in paraffin, using immunohistochemical reaction to detect BDNF. RESULTS: 1. Normal DRG neurons were divided into three categories(large, medium and small) with the cell body diameter 32 microns and 44 microns as the dividing lines. 2. There are 50.87% BDNF positive neurons in normal L6DRG. After operation, the number of BDNF positive neurons of the operated side DRG significantly increased, especially 6 days(76.70%). Normal and postoperative BDNF positive neurons were mainly small neurons. After partial section of DRG, the expression of BDNF in spared DRG neurons increased, which might be involved in promoting collateral sprouting of spared root in spinal cord and rescuing the dorsal horn neurons from partial deafferentation.

Animals↗

PubMed2000

[Study on histology and the expression of Bax and Bcl-2 after cerebral contusion in rats].

To set up the experimental model of focal cerebral contusions in rats, and to study the histology and the expression of Bax and Bcl-2 after cerebral catusions. It was found that neurons and astrocytes around the wound area were changed morphologically and that polymorphonuclear leucocytes were present at 12-24 h after injury. A lot of foamy cells and astrocytes having a big dark nucleus appeared around the wound area on the 4th day after injury. On the 8-10th day, liquefaction necrosis was seen in areas of contusions. On the 12-14th day, the contusion focus healed up and became cystiform or glial node. Meantime, lots of astrocytes, capillary vessel and hemosiderin were observed. The expression of Bax and Bcl-2 increased after injury. There existed a relationship between increased Bax/Bcl-2 and different intervals after brain injury.

Animals↗

PubMed2000

Microsurgical treatment of Mooren's ulcer.

OBJECTIVE: To evaluate effect of microsurgery of lamellar keratoplasty (LKP) on Mooren's corneal ulcer. METHODS: The effect, postoperative astigmatism, postoperative vision, ulcer recurrence of postoperation, and surgical complications of two groups of consecutive Mooren's ulcer inpatients treated respectively by non-microsurgery of LKP and microsurgery of LKP were analyzed. RESULTS: There were significant differences of the effect, postoperative astigmatism, postoperative vision, ulcer recurrence of postoperation, and surgical complications between the two groups. The effect and postoperative vision of the microsurgery-treated group were better than those of the non-microsurgery-treated group. The postoperative astigmatism, ulcer recurrence of postoperation, and surgical complications of the microsurgery-treated group were less than those of the nonmicrosurgery-treated group. CONCLUSION: Microsurgery of LKP of Mooren's corneal ulcer can greatly improve the ulcer healing and postoperative vision, and reduce the surgical complication and the ulcer recurrence of postoperation.

Adolescent↗