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Biomedical subjects

C Lu

Publications and source records attributed to C Lu.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Deletions and aberrant transcription of p16 and p15 genes in childhood acute lymphoblastic leukemia].

OBJECTIVE: To explore the role of p16(MTS1) and p15(MTS2) genes in the pathogenesis of childhood acute lymphoblastic leukemia(ALL). METHODS: PCR and Southern blot were used to analyse p16 and p15 gene deletions, RT-PCR was used to analyse p15 gene transcription. RESULTS: Exon 1 and 2 of p16 gene deletion was detected in 8 of 21 patients(38.1%), and exon 1 and 2 of p15 gene deletion in 11 of 21 patients(52.3%). Aberrant p15 gene transcription was observed in two cases. CONCLUSION: High frequency of p16 and p15 gene deletions and aberrant transcription may be involved in the pathogenesis of childhood ALL.

Adolescent↗
PubMed1999

[Lutembacher's syndrome].

OBJECTIVE: To compare classical and acquired Lutembacher's syndrome (mitral restenosis after percutaneous balloon mitral valvuloplasty) in attempt to know their different in pathophysiology, diagnosis, and surgical treatment. METHODS: The data from 22 cases of classical and acquired Lutembacher's syndrome who underwent surgical treatment in the same period were analyzed. RESULTS: No death occurred in the classical group. In the acquired group the mortality however was 42.8% for those highly complicated with pulmonary hypertension and right heart failure. CONCLUSIONS: Classical Lutembacher's syndrome can be corrected satisfactorily. The acquired one deteriorates rapidly with severe pulmonary hypertension and right heart failure, and needs early surgical intervention reduce the operation mortality.

Adult↗
PubMed1999

[Ciliary neurotrophic factor in the regeneration of facial nerve].

OBJECTIVE: To study the role of CNTF in regeneration of facial nerve. METHOD: SD Rat facial nerves in temporal bones were transected and then combined end to end. In ciliary neurotrophic factor group (n = 30), lesions were covered by gelatin sponge soaked with CNTF. In control group (n = 18), lesions were covered by gelatin sponge soaked with normal saline. 2, 4, 12 weeks after the operation, both CNTF group and SAL group undergone electrophysiology test and histopathology as well as quantity analysis. RESULT: Two weeks later, both CNTF and SAL group failed in eliciting muscular excitement by stimulating facial nerve; T-test showed significant difference between the two groups(P < 0.05) about the average of myelinated axons 4 weeks later, the latency of facial muscular excitement was 7.650 +/- 2.702 ms in CNTF group and 16.080 +/- 0.162 ms in SAL group. The average number of myelinated axons was 1614 +/- 411 in experimental group and 1094 +/- 343 in control group. T-test showed significant difference between them (P < 0.05). 12 weeks later, latency of facial muscle excitement was 2.016 +/- 0.122 ms in CNTF group and 2.060 +/- 0.162 ms in SAL group. The average number of myelinated axons was 1909 +/- 332 in experimental group and 1847 +/- 422 in control group. T-test showed no significant difference between the two groups (P > 0.05). CONCLUSION: CNTF enhance facial nerve regeneration in adult SD rats.

Administration, Topical↗
PubMed1999

[Experimental studies in vitro on the alpha-fetoprotein-specific promoter mediated target gene therapy of hepatocellular carcinoma].

OBJECTIVE: To investigate the alpha-fetoprotein (AFP)-specific promoter mediated target gene therapy of hepatocellular carcinoma in vitro. METHODS: Retroviral vector (LX2.2CD) in which the cytosine deaminase (CD) gene was driven by the 2.2 kb recombinant human AFP TRS. After transfecting three human hepatoma cell lines and one non-hepatoma cell line with LX2.2 CD, anti-G418 clones integrated CD gene were selected, and inhibitory experiment of cell growth was performed. RESULTS: 5-fluorocytosine (5FC) could confer the chemosensitivity to transduced AFP-producing hepatoma cells (HuH-7 and huH-1/c1-2), but not to AFP-nonproducing hepatoma cells (HLE) or nonhepatoma cells (GLC). On the other hand, when transfecting the above four tumor cell lines with another retroviral vector pCD2 (CD gene was driven by 5'LTR internal promoter), no cell selection was found in 5FC-induced cell grow inhibition. CONCLUSIONS: Recombinant retrovival transfer of the CD gene under the control of the AFP TRS followed by 5FC may well be a promising trageted gene therapy for hepatoma.

Antineoplastic Agents↗
PubMed1998

[Preventive and therapeutic effects of calcium lactate on osteoporosis in aged ovariectomized rats].

Twelve-month-old rats were ovariectomized (OVX), remained untreated for one month. Calcium lactate was given daily by gavage at the dose of 125, 250 and 750 mg/kg(Ca125, Ca250, Ca750) for 3 months. The results showed that compared with OVX rats, Ca250 could markedly increase the bone mineral density (BMD) at right femur. Both Ca250 and Ca750 could markedly enhance the ash weight, ratio of ash weight to dry weight of left femur and ratio of 24-hour urinary Ca/Cr. Ca125 could markedly decrease serum ALP concentration. Both Ca125 and Ca250 could decrease the ratio of 24-hour urinary Hop/Cr. All doses of calcium lactate groups could elevate serum Ca, and were no influence on the volume, wet and dry weight of the left femur and serum OC levels. In conclusion, the administration of calcium lactate to aged OVX rats prevents bone resorption, and its mechanism may be relating to the supplement of calcium properly.

Animals↗
PubMed1998

Effects of trimetazidine on ischemic left ventricular dysfunction in patients with coronary artery disease.

We studied 15 patients with chronic coronary artery disease (13 men aged 62 +/- 8 years) undergoing dobutamine (5 to 40 microg/kg/min) echocardiography at the end of two 15-day treatment periods with placebo and trimetazidine (20 mg 3 times daily) given in random order, according to a double-blind, crossover design. Results show that trimetazidine improves resting left ventricular function and reduces the severity of dobutamine-induced ischemic myocardial dysfunction.

Administration, Oral↗
PubMed1998

Antisense fosB RNA inhibits thrombin-induced hypertrophy in cultured pulmonary arterial smooth muscle cells.

BACKGROUND: We have previously reported that fosB mRNA is induced by hypertrophic stimuli (thrombin, angiotensin II) but not proliferative stimuli (platelet-derived growth factor, basic fibroblast growth factor) in pulmonary arterial smooth muscle cells (PASMCs) (J Biol Chem. 1994;9:6399-6404). Our aim in the present study was to investigate the potential role of FosB in PASMC hypertrophy. METHODS AND RESULTS: Adenoviruses carrying sense or antisense fosB RNA expression cassettes were used to infect cultured PASMCs with the aim of increasing or inhibiting fosB expression, respectively. We examined whether fosB expression modification affected the growth of quiescent PASMCs, thrombin-induced hypertrophy, or platelet-derived growth factor-induced proliferation. PASMC growth was assessed by daily cell number count, determination of [3H]leucine incorporation, and quantification of total cellular protein. Neither an increase nor a decrease in FosB protein expression caused a significant change in the growth of quiescent PASMCs over a period of 96 hours, indicating that FosB alone is not sufficient to induce hypertrophy. Modification of FosB levels did not affect platelet-derived growth factor-induced PASMC proliferation. An increase in FosB expression did not augment thrombin-induced hypertrophy; however, inhibition of FosB expression resulted in a diminution of thrombin-induced hypertrophy by 58+/-6% (P<0.005). CONCLUSIONS: These results suggest that FosB is necessary but not sufficient for thrombin-induced hypertrophy in cultured PASMCs.

Antisense Elements (Genetics)↗
PubMed1998

Retinal ganglion cell axon progression from the optic chiasm to initiate optic tract development requires cell autonomous function of GAP-43.

Pathfinding mechanisms underlying retinal ganglion cell (RGC) axon growth from the optic chiasm into the optic tract are unknown. Previous work has shown that mouse embryos deficient in GAP-43 have an enlarged optic chiasm within which RGC axons were reportedly stalled. Here we have found that the enlarged chiasm of GAP-43 null mouse embryos appears subsequent to a failure of the earliest RGC axons to progress laterally through the chiasm-tract transition zone to form the optic tract. Previous work has shown that ventral diencephalon CD44/stage-specific embryonic antigen (SSEA) neurons provide guidance information for RGC axons during chiasm formation. Here we found that in the chiasm-tract transition zone, axons of CD44/SSEA neurons precede RGC axons into the lateral diencephalic wall and like RGC axons also express GAP-43. However unlike RGC axons, CD44/SSEA axon trajectories are unaffected in GAP-43 null embryos, indicating that GAP-43-dependent guidance at this site is RGC axon specific or occurs only at specific developmental times. To determine whether the phenotype results from loss of GAP-43 in RGCs or in diencephalon components such as CD44/SSEA axons, wild-type, heterozygous, or homozygous GAP-43 null donor retinal tissues were grafted onto host diencephalons of all three genotypes, and graft axon growth into the optic tract region was assessed. Results show that optic tract development requires cell autonomous GAP-43 function in RGC axons and not in cellular elements of the ventral diencephalon or transition zone.

Animals↗
PubMed1998

The structure of the beta-propeller domain and C-terminal region of the integrin alphaM subunit. Dependence on beta subunit association and prediction of domains.

The alphaM subunit of integrin Mac-1 contains several distinct regions in its extracellular segment. The N-terminal region has been predicted to fold into a beta-propeller domain composed of seven beta-sheets each about 60 amino acid residues long, with the I-domain inserted between beta-sheets 2 and 3. The structure of the C-terminal region is unknown. We have used monoclonal antibodies (mAbs) as probes to study the dependence of the structure of different regions of the alphaM subunit on association with the beta2 subunit in the alphaM/beta2 heterodimer. All of the mAbs to the I-domain immunoprecipitated the unassociated alphaM precursor and reacted with the alphaM subunit expressed alone on the surface of COS cells. By contrast, four mAbs to the beta-propeller domain did not react with the unassociated alphaM precursor nor with the uncomplexed alphaM subunit expressed on COS cell surface. The four mAbs were mapped to three subregions in three different beta-sheets, making it unlikely that each recognized an interface between the alpha and beta subunits. These results suggest that folding of different beta-propeller subregions is coordinate and is dependent on association with the beta2 subunit. The segment C-terminal to the beta-propeller domain, residues 599-1092, was studied with nine mAbs. A subset of four mAbs that reacted with the alphaM/beta2 complex but not with the unassociated alphaM subunit were mapped to one subregion, residues 718-759, and five other mAbs that recognized both the unassociated and the complexed alphaM subunit were localized to three other subregions, residues 599-679, 820-882, and 943-1047. This suggests that much of the region C-terminal to the beta-propeller domain folds independently of association with the beta2 subunit. Our data provide new insights into how different domains in the integrin alpha and beta subunits may interact.

Amino Acid Sequence↗
PubMed1998

Platelet-derived endothelial cell growth factor/thymidine phosphorylase expression correlated with tumor angiogenesis and macrophage infiltration in colorectal cancer.

To clarify whether platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) expression in both tumor cells and stromal cells has independent or synergistic effects on tumor angiogenesis and progression and to explore a possible regulator for PD-ECGF/TP expression, immunohistochemical staining was conducted on 148 specimens of colorectal cancer. The microvessel count was significantly correlated with the extent of PD-ECGF/TP expression. Macrophage infiltration in tumors with positive TP was significantly higher than in tumors with negative TP (P < 0.001). The Cox model showed that PD-ECGF/TP expression was an independent prognostic factor, although the microvessel count had a stronger value in determining the patient prognosis.

Adenocarcinoma↗
PubMed1998

Salivary concentrations of atrazine reflect free atrazine plasma levels in rats.

The protein binding of atrazine in plasma and its effect on salivary excretion of atrazine was determined in male Sprague-Dawley rats. The degree of protein binding of atrazine was determined at 3 steady-state plasma concentrations, 50, 150, and 250 microg/L, using an ultrafiltration technique. In total, 48 arterial blood samples were collected from 18 rats; 38 of 48 blood samples had their time-matched whole saliva samples. The average protein binding of atrazine ranged from 18% to 37%; however, it was not significantly different across the 3 steady-state plasma concentrations nor among the individual rats. Overall, 26% of atrazine was bound to plasma proteins and not available for transport from blood into saliva. Protein binding of atrazine in plasma was not correlated with total atrazine plasma concentration nor with free atrazine plasma concentration, which indicates that the protein-bound fraction of atrazine is independent of plasma concentration within the range measured in this study (30-400 microg/L). The average saliva/plasma (S/P) concentration ratio of atrazine increased from 0.7 using total atrazine plasma concentration to 0.94 (S/fP) when free atrazine plasma concentrations calculated as 26% of protein binding was used. Salivary concentration was highly correlated with free atrazine plasma concentration. The results suggest that salivary concentration of atrazine not only reflects its total plasma level but accurately measures the portion of atrazine (free atrazine) in plasma, which may be of toxicological significance.

Animals↗
PubMed1998

FtsZ from Escherichia coli, Azotobacter vinelandii, and Thermotoga maritima--quantitation, GTP hydrolysis, and assembly.

We have cloned the ftsZ genes from Thermotoga maritima and Azotobacter vinelandii and expressed the proteins (TmFtsZ and AzFtsZ) in Escherichia coli. We compared these proteins to E. coli FtsZ (EcFtsZ), and found that several remarkable features of their GTPase activities were similar for all three species, implying that these characteristics may be universal among FtsZs. Using a calibrated protein assay, we found that all three FtsZs bound 1 mole guanine nucleotide per mole FtsZ and hydrolyzed GTP at high rates (> 2 GTP per FtsZ per min). All three required magnesium and a monovalent cation for GTP hydrolysis. Previous reports showed that EcFtsZ (and some other species) required potassium. We confirmed this specificity for EcFtsZ but found that potassium and sodium both worked for Az- and TmFtsZ. Specific GTPase activity had a striking dependence on FtsZ concentration: activity (per FtsZ molecule) was absent or low below 50 microg/ml, rose steeply from 50 to 300 microg/ml and plateaued at a constant high value above 300 microg/ml. This finding suggests that the active state requires a polymer that is assembled cooperatively at 50-300 microg/ml. A good candidate for the active polymer was visualized by negative stain electron microscopy--straight protofilaments and protofilament pairs were seen under all conditions with active GTPase. We suggest that the GTP hydrolysis of FtsZ may be coupled to assembly, as it is for tubulin, with hydrolysis occurring shortly after an FtsZ monomer associates onto a protofilament end. As a part of this study, we determined the concentration of EcFtsZ and TmFtsZ by quantitative amino acid analysis and used this to standardize the bicinchonic acid colorimetric assay. This is the first accurate determination of FtsZ concentration. Using this standard and quantitative Western blotting, we determined that the average E. coli cell has 15,000 molecules of FtsZ, at a concentration of 400 microg/ml. This is just above the plateau for full GTPase activity in vitro.

Actin Cytoskeleton↗
PubMed1998

Impact of chronic patency of infarct-related coronary artery on prevalence of myocardial ischemia during the pharmacologic and exercise stress test.

BACKGROUND: Even late restoration of anterograde coronary flow may have beneficial effects on left ventricular function, electrophysiology, and survival in postinfarction patients. HYPOTHESIS: The patency or occlusion of an infarct-related coronary artery in the chronic phase may also be associated with myocardial ischemia provoked by pharmacologic and physiologic stress tests. METHODS: High-dose dipyridamole echocardiography test (DET) (up to 0.84 mg/kg over 10 min), exercise electrocardiography (EET), and coronary angiographic data in a group of 127 in-hospital patients who had survived an acute myocardial infarction were analyzed. Patients who had only angiographic evidence of infarct-related single artery disease (> or = 50% luminal diameter reduction) and no previous revascularization were enrolled in the study. DET and EET were performed (DET in all, EET in 118 patients) within 5 days before coronary angiography. Fifty-seven patients had total occluded infarct arteries (Group 1) with various degrees of collateral circulation (2.6 +/- 1.1 collateral score, by a 3 grading system), whereas the other 70 patients had patent infarct arteries (Group 2) with significant residual stenoses (82 +/- 13% diameter reduction). RESULTS: The prevalence of rest angina or effort angina and topography of the infarct-related coronary artery did not differ between the two groups (all p = NS). There were more patients with Q wave in Group 1 than in Group 2 (72 vs. 57%, p = 0.08) compared with non-Q wave infarction (Group 1 = 28 vs. Group 2 = 43%, p = 0.08). Ischemia in the infarct-related artery territory detected by DET (defined as new wall motion dyssynergy or marked worsening of resting hypokinesia) was 61% in Group 1 and 41% in Group 2 (p = 0.025). EET was positive in 26 of 54 (48%) Group 1 and in 21 of 64 (33%) Group 2 patients (p = 0.09). CONCLUSIONS: Patients with occluded infarct-related arteries have a higher prevalence of ischemia during DET and EET regardless of the presence of collateral flow. These results suggest that the presence of partial anterograde flow in the prolonged period could have a favorable influence on prevalence of residual ischemia in these patients.

Blood Flow Velocity↗
PubMed1998

Maximizing pregnancy rates and limiting higher-order multiple conceptions by determining the optimal number of embryos to transfer based on quality.

OBJECTIVE: To define statistical thresholds for the number of embryos to be transferred to achieve an optimal pregnancy rate and keep higher-order multiple conceptions (pregnancy with more than two fetal sacs with cardiac activity) within an acceptable limit. DESIGN: A retrospective review of patient records. SETTING: Private practice assisted reproductive technology (ART) facility. PATIENT(S): Seven hundred fifty-four consecutive patients who underwent IVF-ET from 1994-1996. INTERVENTION(S): Embryo grading and score system used on day 3 of embryo transfer. MAIN OUTCOME MEASURE(S): Implantation, pregnancy, and multiple conception rates. RESULT(S): For women < or =35 years old, transfer of up to four poor-quality, two fair-quality, or two good-quality embryos is optimal to eliminate any risk of higher-order multiple pregnancies. Transfer of four poor-quality, three fair-quality, or two good-quality embryos is recommended for women 36 to 39 years old. In women who are > or =40 years old, five embryos need to be transferred regardless of embryo quality. CONCLUSION(S): The mean cumulative embryo score can be used as a reference to determine an optimal number of embryos to transfer and to predict pregnancy outcome.

Adult↗
PubMed1998

Suspected spinal cord compression in breast cancer patients: a multidisciplinary risk assessment.

Breast cancer is the most common cause of metastatic epidural spinal cord compression (SCC) in women, and this condition results in significant neurologic dysfunction and morbidity. Prior studies of patients with suspected SCC did not employ multivariate analysis techniques, often included persons with a wide variety of malignancies, and generally focused on identifying associated neurologic and radiologic features. We therefore conducted a study examining a more comprehensive set of potential clinical risk factors in breast cancer patients with suspected SCC. We retrospectively analysed 123 episodes of suspected SCC among 93 breast cancer patients evaluated by spine computed tomography (CT) scanning. Multiple logistic regression analysis was employed to identify independent predictors of SCC. Clinically significant metastatic epidural cancer was defined as thecal sac compression (TSC), which occurred in 33 episodes (27%). Four independent predictors of TSC were identified and included oncologic features (known bone metastases > or = 2 years, metastatic disease at initial diagnosis) in addition to neurologic and radiologic features (objective weakness, vertebral compression fracture on spine radiograph). These four predictors stratified episodes into subgroups with widely varying risks of TSC, ranging from 12% (0 risk factors) to 85% (> or = 3 risk factors). These results suggest that the evaluation of breast cancer patients with suspected SCC should include clinical information about their disease course in addition to neurologic examination and prior imaging studies. If confirmed, these predictors may help clinicians assess risk in this patient population.

Adult↗
PubMed1998

Actin depolymerization affects stress-induced translational activity of potato tuber tissue

Changes in polymerized actin during stress conditions were correlated with potato (Solanum tuberosum L.) tuber protein synthesis. Fluorescence microscopy and immunoblot analyses indicated that filamentous actin was nearly undetectable in mature, quiescent aerobic tubers. Mechanical wounding of postharvest tubers resulted in a localized increase of polymerized actin, and microfilament bundles were visible in cells of the wounded periderm within 12 h after wounding. During this same period translational activity increased 8-fold. By contrast, low-oxygen stress caused rapid reduction of polymerized actin coincident with acute inhibition of protein synthesis. Treatment of aerobic tubers with cytochalasin D, an agent that disrupts actin filaments, reduced wound-induced protein synthesis in vivo. This effect was not observed when colchicine, an agent that depolymerizes microtubules, was used. Neither of these drugs had a significant effect in vitro on run-off translation of isolated polysomes. However, cytochalasin D did reduce translational competence in vitro of a crude cellular fraction containing both polysomes and cytoskeletal elements. These results demonstrate the dependence of wound-induced protein synthesis on the integrity of microfilaments and suggest that the dynamics of the actin cytoskeleton may affect translational activity during stress conditions.

Journal Article↗