Biomedical subjects

S Liu

Publications and source records attributed to S Liu.

At least 379 records · Page 21Linked to original sources

PubMed2000

[Preliminary echocardiographic evaluation on prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis].

The purpose of this study was to evaluate the preliminary results after prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis. 20 patients had received operation with expanded polytetrafluoroethylene(e-PTFE) as artificial chordade. The patients were followed up by means of echocardiography. The time of follow-up study varied from 4 to 18 months with a mean of 6 months. The left atrial, ventricular dimension as well as ventricular function were assessed. In addition, the length of artificial chorade and obstruction of left ventricular outflow track were observed. The results showed that left atrial diameter (LAD, from 57.59 +/- 13.51 mm to 47.05 +/- 9.55 mm), left ventricular end-diastolic dimension (LVEDD, from 46.23 +/- 12.56 mm to 42.41 +/- 10.86 mm), left ventricular end-systolic dimension (LVESD, from 33.50 +/- 10.20 mm to 29.68 +/- 8.40 mm) decreased (P < 0.01), and ejection fraction (EF, from 52.59 +/- 11.89% to 58.36 +/- 8.03%) increased (P < 0.05) after operation. There were no significant changes of fractional shortening (FS, from 29.23 +/- 8.99% to 31.05 +/- 6.08%). The length of artificial chorade ranged from 2.6 cm to 4.3 cm (the mean, 3.2 cm). There was no case of obstruction of left ventricular outflow track. It is believed that the result of preliminary echocardiographic observation on prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis is satisfactory.

Adult↗

PubMed2000

[Study of spontaneous echo contrast in patients with rheumatic mitral stenosis by transesophageal echocardiography].

Spontaneous echo contrast (SEC) is common in the areas of slow blood flow. This study was conducted to examine the correlation of SEC and left atrial appendage function, atrial fibrillation (Af) and thrombus in patients with rheumatic mitral stenosis. The transthoracic and multiplane transesophageal echocardiograms were performed on 117 patients(mean age 42.22 +/- 10.79 years). Left atrial size, left atrial appendage area, mitral valve area, left atrial appendage flow peak emphatic velocity and full velocity were measured. The presence of SEC and thrombus in the left atrium and appendage was noted. The results showed that among the patients, 57 had normal sinus rhythm, 60 had Af; 19 had thrombus, 98 had no thrombus; 71 had SEC and 46 had no SEC. Compared with the patients without SEC, the patients with SEC showed greater incidence of thrombus (28.76% vs 0, P < 0.05), higher rate of Af (69.01% vs 23.91%, P < 0.05), larger LAD (46.93 +/- 0.85 mm vs. 41.76 +/- 1.05 mm, P < 0.05), larger LAA area (8.06 +/- 0.32 cm2 vs 6.92 +/- 0.31 cm2, P < 0.05), smaller MVA area (1.07 +/- 0.23 cm2 vs 1.32 +/- 0.35 cm2, P < 0.05), lower LAA flow peak emphatic velocity (0.17 +/- 0.01 m/s vs 0.32 +/- 0.02 m/s, P < 0.05), and lower LAA full velocity (0.18 +/- 0.01 m/s vs 0.31 +/- 0.03 m/s, P < 0.05). These findings indicate that the presence of SEC is associated with significantly greater incidence of thrombus, higher rate of Af, larger LAD and LAA area, smaller MVA area, lower LAA flow peak emphatic velocity and full velocity. Atrial fibrillation, the diameter of left atrium and the area of mitral valve are independent predictors of SEC. SEC is significantly associated with LAA function and thrombus formation.

Adolescent↗

PubMed2000

[An adenosine triphosphate bioluminescence assay for detecting the number of living cells].

The method for detecting the number of living cells was studied. Using an adenosine triphosphate (ATP) bioluminescence assay, the present authors reported a perfect linear relationship between lg ATP concentrations and lg luminescence counts (r = 0.9963) as well as a relationship between lg number of cells and lg ATP luminescence counts (r = 0.9922). The detectable cells ranged from 10(2) to 10(6) cells/ml, the coefficients of variation 1-3%. This method is simple, accurate and sensitive and has a high reproducibility.

Adenosine Triphosphate↗

PubMed2000

[An experimental study of transplantation of prefabricated axial flap with an vascular bundle].

OBJECTIVE: To study the prognostic results of different prefabricated axial flaps with different operative methods. METHODS: Eighteen New Zealand rabbits and two operative patterns were utilized in this study. In group A, the vascular bundles of the left ear were transferred through tube flaps to the left neck. In group B, the central artery and veins of the right ear were transposed through skin tunnel to the right neck. After 4 weeks of operation, transplantation and vessel perfusion were made. RESULTS: Group A: The flaps of 10 cases were 100% survival, while there were 2 cases with 85% survival, and 2 flaps with necrosis. Group B: The flaps of 8 cases were 100% survival, while there were 5 sides with 50%-85% survival and 1 necrotic flap. The vessel perfusion demonstrated that there was no difference between the density values of the direct sprouting vessels from the transplanted vascular pedicles. There was no statistical difference between the two groups in flap survival and vessel perfusion. CONCLUSION: There is no obvious difference between the above two methods of prefabricated axial flap.

Animals↗

PubMed2000

[Quantitative and immunohistochemical analysis of endothelin-1 in oral submucous fibrosis].

OBJECTIVE: This experiment is carried out to investigate roles of endothelin-1 (ET-1), a potent vasoconstrictor and mitogenic peptide, in fibrosis and collagen production. METHODS: 30 cases of oral submucous fibrosis(OSF), 10 cases of oral lichen planus (OLP) and 10 cases of normal control, were studied by means of SABC immunohistochemical method with polyclonal antisera to ET-1 and using image pattern analysis technique. RESULTS: 1. Oral mucosa from OLP and normal control expressed very little ET-1. By contrast, there was striking expression of ET-1 in oral mucosa from OSF; 2. The cellular content of ET-1 in OSF was significantly higher than that in normal control (P < 0.01), while the cellular content of ET-1 in the early and moderate stages OSF were significantly higher than that in the advanced stage(P < 0.01); 3. The cellular content of ET-1 in the early and moderate stages OSF were significantly higher than that in OLP(P < 0.01); 4. There was a significantly positive correlation between cellular contents of epithelia and interstitial(P < 0.05). CONCLUSION: These findings suggest that cell-specific expression of ET-1 may play a role in pathogenesis of OSF.

Endothelin-1↗

PubMed2000

[Experimental studies on exons 5-8 of p53 gene mutation in laryngeal squamous cell carcinoma].

This study was designed to detect the point mutations of exons 5-8 of p53 gene in laryngeal squamous cell carcinoma (LSCC) and analyze their relationship. The detection of fresh tumor samples from LSCC patients was performed using silver staining PCR-SSCP method. From among 60 patients samples, 47 were positive in SSCP. Mutation rate was 78.3% (47/60). The results showed that the prevalence of p53 mutations in LSCC subjected to silver staining PCR-SSCP test were 50% (30/60) in exon 5, 11.67%(7/60) in exon 6, 41.6%(25/60) in exon 7, and 25%(15/60) in exon 8. The majority of the mutations were found in exon 5 and exon 7. Exon 5 and exon 7 of p53 gene may be the mutation hotspot in LSCC; they may be the critical position easily attacked by some carcinogen factors relating to LSCC.

Carcinoma, Squamous Cell↗

PubMed2000

[An evaluation of adenosine triphosphate bioluminescence assay for tumor in vitro chemosensitivity testing].

This study was aimed at the feasibility of using ATP-bioluminescence assay for tumor in vitro chemosensitivity testing. With the use of this assay, the authors determined dose-response curve in mouse fibroma cell line L929 treated with chemotherapeutic agents, and investigated the different in vitro responses of 6 ovarian carcinomas (5 from fresh tumor tissues, 1 from ascites) treated with etopside, cis-plating, 5-fluorouracil and adriamycin. The results showed that the coefficients of variation for triplicate assays ranged from 1.2% to 15.8% which means high reproducibility of the assay. The single cell suspension (including < 30 cells clusters) could be separated from tissue fragments by means of enzyme cocktail (collagenase, Dnase, pronase). The viable cells were over 90%. This study demonstrates that ATP-bioluminescence assay is a sensitive, reliable and efficient method for tumor chemosensitivity testing. In this connection, the correlation between in vitro drug sensitivity and in vivo patient response is worth further studying.

Adenosine Triphosphate↗

PubMed2000

[Study on fermentation of 1,13-tridecanedioic acid by Candida tropicalis].

A mutant of Candida tropicalis SP-1, SP-UV-56, which can produce 1,13-tridecanedioic acid or 1,11-dicarboxylic acid (DCA13) 1.25 times as much as its parental strain SP-1, but hardly assimilates nalkane as carbon source for its growth, was obtained by ultraviolet treatments. A fermentation technology with a supplement of acetate at the latter middle of logarithmic growth was developed. Using sucrose as carbon source for its growth and supplying acetate the yield of DCA13 reached 153 g/L for 144 h incubation in a 13.7 L auto-controlled stirred tank, about 29.7% higher than that obtained in the broth without acetate. An effective technique that can maintain higher yield was provided by enhancing mixing of broth and controlling low DO level. With these techniques the DCA13 yield reached 172 g/L in a 20 m3 stirred tank, and produced 2.25 tons DCA13 in 15.0 m3 broth.

Alkanes↗

PubMed2000

[Supercritical extraction of Alpinia officinarum and GC-MS analysis of its components].

In order to find the effective components and new pharmaceutical effect of Alpinia officinarum, and further exploit it, we extracted its essential oils with the technique of Supercritical-CO2 fluid, then confirmed there were 27 components in Pot I And 111 components in Pot II by using the chemical component analysis and the computer information retrieval in the GC-MS system.

Alpinia↗

PubMed2000

[mRNA expression of keratoepithelin in cornea after photorefractive keratectomy in rabbits].

OBJECTIVE: To investigate the roles of keratoepithelin(KE) during healing after photorefractive keratectomy (PRK). METHODS: 20 of 24 rabbits underwent bilateral 193 nm excimer laser photorefractive keratectomy to correct 10 diopters of myopia, and the other 4 rabbits as normal group. The mRNA levels of KE in corneas of the rabbits were determined by the in situ hybridization technique with a Digoxigenin labled probe. RESULTS: In normal group, there was no mRNA expression of KE in cornea. on 7, 14 days after operation, mRNA expression of KE was observed in epithelium and stroma of operation group, while on 28 days mRNA expression of KE was observed only in epithelium. CONCLUSION: KE was involved in the synthesis of extracellular matrix during healing after PRK and may play an important role in the development of haze by maintaining proper spacing among collagen fibrils.

Animals↗

PubMed2000

[Simultaneously corneal laceration repair, traumatic cataract removal and intraocular lens implantation].

OBJECTIVE: The study aimed to evaluate the outcome of patients who undrwent simultaneously corneal laceration repair, cataract extraction and posterior chamber lens implantation. METHODS: Traumatic cataract extraction and posterior chamber intraocular lens (PC IOL) implantation were performed in 36 eyes of 36 cases with corneal laceration. YAG laser was the postoperative procedure for embrane before the lens and after cataract. Penetrating keratoplasty was performed for central cicatrice of cornea. All the patients have been followed up for 3-12 months. RESULTS: The postoperative visual acuity s.c. was 0.1-0.3 in 8 cases(22.8%), 0.4-0.5 in 14 cases (40%) 0.6-0.8 in 13 cases (37.1%) on following up. There were no serious complication attributable to PC IOL implantation. CONCLUSION: As long as the range of surgical indication was known well, PC IOL implantation can get good clinical effects at the time of primary repair.

Adolescent↗

PubMed2000

[Multiple factors analysis of myopic regression after photorefractive keratectomy].

PURPOSE: To investigate myopic regression after excimer laser photorefractive keratectomy(PRK) in patients with myopia. METHODS: PRK was performed to correct myopia errors from 1.00 D to 16.00 D diopters on 214 myopia eyes(121 patients). All eyes were divided into two groups: group I--1.00 D(-)-6.00 D (124 eyes), group II--6.25 D(-)-16.00 D(90 eyes). All the patients were followed up for two years. RESULTS: A Significant positive correlation was found between the regression and the extents of attempted correction. The rate of regression in mild to moderate myopia group was 9.7% while in highter group it was 27.8% (P < 0.005). The rate of regression of older age group in lighter myopia group was highter than that in younger case (P < 0.005). Relatively severe haze under the corneal epithelium often accompanies the regression. CONCLUSION: The main factors which caused the myopia regression after PRK was the extent of attempted correction, patients' age and corneal haze.

Adolescent↗

PubMed2000

[Evaluation of polymerase chain reaction for detection of chlamydia trachomatis in eye swabs].

OBJECTIVE: To investigate the clinical value of Polymerase Chain Reaction (PCR) in the diagnosis of trachoma. METHODS: Direct amplication of 16S rRNA gene which is chlamydia-specific by PCR was used to detect chlamydia trachomatis (CT). RESULTS: Of 93 subjects who conformed to the diagnosis criteria of trachoma, 69 (74.2%) was PCR-Positive; Of 178 subjects who did not comform to the criteia, 6(3.4%) was PCR-positive. PCR had a sensitivity of 74.2% and a speciticity of 96.7% for the clinical diagnosis of trachoma. The difference between trachoma group and nontrachoma group is significant(P < 0.001). CONCLUSION: The PCR may be a good method in the diagnosis of ocular chlamydia trachomatis infection because of its excellent sensitivity and specificity.

Adolescent↗

PubMed2000

[Analysis of refractive state after excimer laser photorefractive keratectomy in myopia].

OBJECTIVE: To evaluate refractive state after excimer laser photorefractive keratectomy (PRK) in patients with myopia. METHODS: 234 cases(391 eyes) followed up for two years were divided into two groups, group I: mild and moderate myopia(< or = -6.00 D), 228 eyes; group II: High myopia(> -6.00 D), 163 eyes. The refractive state of patients at three, six, twelve and twenty-four months postoperatively were monitored. RESULTS: At two years after photorefractive keratectomy (PRK), refractive regression (> -0.5 D), overcorrection(> 1.00 D), undercorrection(> 1.00 D), postoperative residual astigmatism postoperative astigmatism and hyperopia shift in group I were 1.7%, 4.4%, 5.7%, 12.8%, 7.4% and 7.5% respectively, while in high myopia group were 15.9%, 4.9%, 23.3%, 29.7%, 31.1% and 6.7% respectively. CONCLUSION: The results prove that photorefractive keratectomy is an effective, precise, stable and safe method for correction of mild and moderate myopia, but insufficient for high myopia.

Adolescent↗

PubMed2000

[Detection of bcl-2/JH gene rearrangement by semi-nested polymerase chain reaction from fresh tumor samples in patients with laryngeal squamous cell carcinomas].

OBJECTIVE: To evaluate the clinical implications of bcl-2/JH gene rearrangement in laryngeal squamous cell carcinomas (LSCC). METHODS: Bcl-2/JH gene rearrangement analysis in fresh tumor samples was performed in 60 patients with LSCC by semi-nested polymerase chain reaction(PCR). RESULTS: The results showed that bcl-2/JH gene rearrangement was found in 37 out of 60 patients. The breakpoint was located within the major breakpoint region(mbr) in 33 of the 60 patients and the remaining patients had bcl-2 translocation within the minor cluster region(mcr). The results of the study showed that the rearrangement rate of bcl-2 gene was not related to the grade of differentiation, clinical stage, and neck lymph-node metastasis (P > 0.05), and it was related to heavy smoking (P < 0.05). CONCLUSION: Detection of bcl-2/JH gene rearrangement could reveal that bcl-2/JH fusion gene in LSCC is an important molecular biological marker and has a significant role in occurrence and development of LSCC.

Adult↗

PubMed2000

Involvement of the Ca(2+)-protein kinase C and adenyilate cyclace signal pathways in the activation of thymocytes in response to whole-body irradiation with low dose X-rays.

OBJECTIVE: To study the molecular mechanism of the stimulatory effect of low dose radiation (LDR) on T cell activation. METHODS: Thymocytes from Kunming mice exposed to whole-body irradiation (WBI) with different doses of X-rays were analyzed for the changes in signal molecules of the phospholipase C-phosphatidylinositol biphosphate (PLC-IP2) and G protein-adenylate cyclase (AC) pathways. RESULTS: It was found that [Ca2+]i increased in response to doses within 0. 2 Gy which was most marked after 0. 075 Gy and the increase was accentuated in the presence of Con A. The changes in CD3 and calcineurin (CN) expression of the thymocytes followed the same pattern as the alterations in [Ca2+]i after LDR. The expression of alpha, beta1 and beta2 isoforms of protein kinase C (PKC) was all up-regulated after 0.075 Gy with the increase in PKC-beta1 expression being most marked. The cAMP/cGMP ratio and PKA activity of the thymocytes was lowered after low dose radiation and increased after doses above 0. 5 Gy in a dose-dependent manner, thus giving rise to J-shaped dose-response curves. The Ca antagonist TMB-8 and cAMP stimulant cholera toxin suppressed the augmented thymocyte proliferation induced by LDR. CONCLUSION: Data presented in the present paper suggest that activation of the PLC-PIP2 signal pathway and suppression of the AC-cAMP signal pathway are involved in the stimulation of the thymocytes following WBI with low dose X-rays.

Animals↗

PubMed2000

Dobutamine magnetic resonance imaging predicts contractile reserve of chronically dysfunctional myocardium: comparison with was fluorine-18 fluorodeoxyglucose positron emission tomography.

OBJECTIVE: This study sought to investigate whether low-dose dobutamine-MRI can detect residual myocardial viability in patients with chronic myocardial infarction and, left ventricular dysfunction. METHODS: Eleven patients with chronic myocardial infarction and left ventricular dysfunction were employed for identification of viable myocardium by cine-MRI during dobutamine infusion. All patients underwent coronary angiography and left ventriculography, 18FDG-PET, MRI at rest and stress. The systolic wall thickening measured at rest and during stress was compared with the results of 18FDG-PET, respectively. RESULTS: A significant difference of either dobutamine-induced systolic wall thickening (SWthstress) or dobutamine-induced contractile reserve (deltaSWth = SWthstress - SWthrest) was present between viable and scar regions (1.0 +/- 0.3 versus -0.3 +/- 0.1, P < 0.01; 1.0 +/- 0.3 versus -0.2 +/- 0.2, P < 0.01). CONCLUSIONS: obutamine-induced contractile reserve can be predicted in the regions of akinesia or dyskinesia at rest when systolic wall thickening was > or = 1.0 mm during dobutamine stimulation.

Adult↗

PubMed2000

[Expression and kinase activity of B-Raf and Raf-1 in leukemia cell lines].

OBJECTIVE: To study expression and kinase activity of B-Raf and Raf-1 kinases in several leukemia cells and normal peripheral blood lymphocytes. METHODS: Western blot was carried out to detect expression of B-Raf and Raf-1 in peripheral blood lymphocytes and leukemia cells. Kinase activities of Raf-1 and B-Raf were analyzed by immunoprecipitation and Western blot. RESULTS: The expression levels of Raf-1 were similar in tested leukemia cells and normal peripheral blood lymphocytes, and Raf-1 protein was all minimally tyrosine-phosphorylated. B-Raf expressed in all tested leukemia cells, but not in normal peripheral blood lymphocytes, and B-Raf was highly activated in Jurkat and K562 leukemia cells. CONCLUSION: The abnormal expression and kinase activity of B-Raf in leukemia cells might be related to leukemia etiologically.

Humans↗