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Biomedical subjects

C Liu

Publications and source records attributed to C Liu.

At least 253 records · Page 14Linked to original sources
PubMed2000

Peptide YY augments gross inhibition by vitamin E succinate of human pancreatic cancer cell growth.

BACKGROUND: Vitamin E succinate (VES) significantly inhibits cell growth in vitro in breast, prostate, and skin cancer cell lines. Our study demonstrated similar inhibitory effects on Mia PaCa-2 pancreatic cancer cells at the same concentration of VES (10 pg/ml). Peptide YY (PYY) also inhibits pancreatic cancer cell growth in vitro. We observed a significant additive effect on growth inhibition in Mia PaCa cells treated with both VES and PYY. METHODS: Human pancreatic ductal adenocarcinoma Mia PaCa-2 cells were cultured and treated once with either 10 pg/ml of VES or 500 pmols of PYY or with both agents together. The control group received an equivalent volume of solvents. MTT assay was performed at 24, 48, and 72 h to evaluate cell viability. RESULTS: Pancreatic cancer cell growth was reduced in all groups treated with PYY and VES. Student's t test was used to analyze the data for each treatment group. At 72 h, both PYY and vitamin E significantly inhibited cell growth compared to control. Combining the agents resulted in a dramatic additive inhibition of growth. CONCLUSION: PYY and vitamin E both inhibit growth of pancreatic cancer cells in vitro with a significant increase in effect when used in combination.

Cell Division↗
PubMed2000

Effect of coriaria lactone on membrane potential of hippocampal neurons in rats.

Intracellular recording method of electrophysiology was used to study the effect of microinjection of coriaria lactone (CL) into hippocampus on membrane potential of hippocampal neurons in rats. The membrane potential in 34 neurons of 12 rats were recorded. The results showed that CL induced depolarization of all of 34 neurons examined. Among the 34 neurons, 15 had paroxysmal depolarization accompanied by spike discharge in cluster and spike discharge in cluster ceased when membrane was hyperpolarized, 7 showed continuous depolarization accompanied by continuous spike discharge and 12 had only depolarizing response. The results suggest that injection of CL into hippocampus may lead to an increase of excitability of local neurons accompanied by different patterns of epileptioform discharge.

Animals↗
PubMed2000

Ryanodine- and thapsigargin-insensitive Ca2+-induced Ca2+ release is primed by lowering external Ca2+ in rabbit autonomic neurons.

Rises in cytosolic Ca2+ induced by a high K+ concentration (30 or 60 mM) (K+-induced Ca2+ transient) were recorded by fluorimetry of Ca2+ indicators in cultured rabbit otic ganglion cells. When external Ca2+ ([Ca2+]o) was reduced to a micromolar (10-40 microM) or nanomolar (<10 nM) level prior to high-K+ treatment, K+-induced Ca2+ transients of considerable amplitude (50% of control) were generated in most cells, although those initiated at normal [Ca2+]o were reduced markedly or abolished by reducing [Ca2+]o during exposure to a high K+ concentration. Lowering [Ca2+]o alone occasionally caused a transient rise in cytosolic Ca2+. K+-induced Ca2+ transients at micromolar [Ca2+]o were repeatedly generated and propagated inwardly at a speed slower than that at normal [Ca2+]o, while those at nanomolar [Ca2+]o occurred only once. K+-induced Ca2+ transients at micromolar [Ca2+]o were not blocked by ryanodine (10 microM), carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP, 5 microM: at 20-22 degrees C but blocked at 31-34 degrees C) or thapsigargin (1-2 microM), but were blocked by Ni2+ (1 mM) or nicardipine (10 microM). Thus, there is a ryanodine-insensitive Ca2+-release mechanism in FCCP- and thapsigargin-insensitive Ca2+ stores in rabbit otic ganglion cells, which is primed by lowering [Ca2+]o and then activated by depolarization-induced Ca2+ entry. This Ca2+-induced Ca2+ release may operate when [Ca2+]o is decreased by intense neuronal activity.

Animals↗
PubMed2000

Correlations between measures of atherosclerosis change using carotid ultrasonography and coronary angiography.

Few studies have examined the correlation between change in carotid artery intima-media thickness (IMT) and change in coronary artery disease. In the Cholesterol Lowering Atherosclerosis Study, current nonsmoking men with coronary artery disease were randomized to colestipol-niacin or placebo. Among 133 subjects with baseline and on-trial coronary angiography and carotid ultrasonography, colestipol-niacin treatment significantly reduced progression of atherosclerosis by both end point measures (2-year average change in percent diameter stenosis by coronary angiography and rate of change in carotid IMT). Significant correlations between change in common carotid artery IMT and quantitative coronary angiographic measures of change were evident over all coronary artery lesions, and in mild/moderate (<50% diameter stenosis), but not severe (>/=50% diameter stenosis) coronary artery lesions. In mild/moderate lesions, correlations with change in common carotid IMT were: percent diameter stenosis (r=0.28, P=0.002), minimum lumen diameter (r=-0.28, P=0.002), and vessel edge roughness (r=0.25, P=0.003). While measures obtained by carotid ultrasonography and coronary angiography are correlated, they each assess different aspects of atherosclerosis change.

Adult↗
PubMed2000

Microvasculature and VEGF expression in cartilaginous tumors.

We examined the microvasculature and VEGF expression in 26 cartilaginous lesions (CL) including 5 enchondromas, 9 grade 1 chondrosarcoma (CS), 6 grade 2 CS, 4 grade 3 CS, 1 mesenchymal, and 1 myxoid chondrosarcoma. The degree of neovascularization was measured by counting microvessels on H&E and factor VIII related antigen immunostained slides. Vessels were divided into pericartilage vessels (PCV) and intracartilage vessels (ICV). PVC comprised vessels around the lobules or invading the lobules but themselves surrounded by noncartilaginous stroma (ie, fibrous stroma); ICV consisted of those vessels present inside the tumoral nodules and in direct apposition with malignant cells or tumoral stroma. A direct correlation was seen between histological type and grade of CS and pericartilage vessels. In contrast, ICV were found only in higher-grade CS. No enchondromas and only 1 of 9 grade 1 CS had ICV. This patient had Ollier's disease. All but 2 of the grade 2 CS showed ICV (average, 20.5). The exceptions were predominantly grade 1 CS with focal grade 2 areas and extensive areas of necrosis. All but 1 grade 3 CS had ICV, the exception being a case of metastatic CS to the lung. Malignant chondrocytes of high-grade lesions stained strongly for vascular endothelial growth factor (VEGF), a potent angiogenic factor. The only high-grade tumors that did not express VEGF did not show ICV either. Enchondromas and grade 1 CS, most without ICV, did not express VEGE In summary, PCV are present in all categories of tumoral cartilage and the number increases with histological grade; ICV are found in high-grade lesions, and the exceptions show extensive necrosis; VEGF expression by malignant chondrocytes is seen in high-grade lesions almost exclusively, and among these in those lesions that showed intracartilage vessels. It is possible that PCV are involved in supporting tumor growth, whereas ICV might be involved in the acquisition of metastatic potential by cartilage tumors. VEGF expression is strongly associated with the presence of ICV.

Bone Neoplasms↗
PubMed2000

No-scalpel vasal sperm aspiration and in vitro fertilization for the treatment of anejaculation.

OBJECTIVES: To evaluate the utility of no-scalpel vasal sperm aspiration and in vitro fertilization for the treatment of male infertility due to anejaculation. METHODS: Vasal aspiration was performed using a no-scalpel technique, and the sperm were used for conventional in vitro fertilization in 1 patient and intracytoplasmic sperm injection in 6 patients. RESULTS: The average total sperm count was 6 x 10(6), with the motility between 20% and 95%. No complications have been observed to date. A high fertilization rate (74.6%) and pregnancy rate (5 of 7) was achieved with subsequent intracytoplasmic sperm injection or in vitro fertilization. CONCLUSIONS: No-scalpel vasal sperm aspiration is a simple, effective alternative to sperm retrieval, especially for anejaculatory males.

Adult↗
PubMed2000

Rats exhibiting acute behavioural tolerance to nicotine have more [125I]alpha-bungarotoxin binding sites in brain than rats not exhibiting tolerance.

Adult male Sprague-Dawley rats trained to discriminate nicotine (0.4 mg/kg, s.c. vs vehicle) using a two-lever food-reinforced operant discriminative stimulus (DS) paradigm were tested as to the ability of each subject to develop acute tolerance to nicotine. Nicotine (0.8 mg/kg, s.c.) was administered to nicotine-trained rats in their home cage and each rat tested as to its ability to detect a 2nd dose of nicotine (0.4 mg/kg, s.c.) injected at 30 min intervals thereafter (90-180 min). Tolerance was determined by evaluating nicotine-correct responding during a 2 min test session. The results of this experiment indicated that 8 out of 31 rats (26%) displayed acute tolerance (desensitizers); 18 rats (58%) did not exhibit acute tolerance (non-desensitzers) and five rats (16%) fell into a middle group and were designated as neither desensitizers or non-desensitizers. The mode time for acute tolerance was 150 min, with each desensitizer rat displaying a unique temporal profile which was replicable 4-5 weeks later. Receptor autoradiographic analysis indicated no significant differences in [3H]epibatidine binding sites in the brains of desensitizers and non-desensitizers. In contrast, [125I]alpha-bungarotoxin binding was significantly higher in a number of brain regions in desensitizers. In situ hybridization analysis revealed no difference in alpha7 nAChR subunit mRNA levels between desensitizers and non-desensitizers. These observations can be interpreted to suggest that the ability to display acute tolerance to nicotine is contingent upon the ability to upregulate alpha7 nAChRs. These data may also be central to understanding the variability of tobacco use in humans, which may be contingent on the ability of the receptors binding to alpha-bungarotoxin to be responsive to nicotine-induced desensitization.

Animals↗
PubMed2000

GABA synchronizes clock cells within the suprachiasmatic circadian clock.

The master clock in the suprachiasmatic nuclei (SCN) is composed of multiple, single-cell circadian clocks. We test the postulate that these individual "clock cells" can be synchronized to each other by the inhibitory transmitter gamma-aminobutyric acid (GABA). For these experiments, we monitored the firing rate rhythm of individual clock cells on fixed multielectrode plates in culture and tested the effects of GABA. The results show that the daily variation in responsiveness of the SCN to phase-shifting agents is manifested at the level of individual neurons. Moreover, GABA, acting through A-type receptors, can both phase shift and synchronize clock cells. We propose that GABA is an important synchronizer of SCN neurons in vivo.

Action Potentials↗
PubMed2000

Investigation of ACTBP2 mutations in the Japanese population.

In the investigation of ACTBP2 (human beta-actin related pseudogene H-beat-Ac-psi-2) mutation in the Japanese population, 230 meioses were analyzed, and two cases of paternal mutations were observed. Paternity confirmation analyses were carried out using seventeen genetic marker systems including erythrocyte antigens, HLA types, D1S80, and nine STR loci contained in the AmpFlSTR Profiler Kit. Excluding ACTBP2, the paternity probabilities for the two cases were each calculated to be over 99.99%. Genotyping of the ACTBP2 locus was performed using the fluorescence detection method under denaturing conditions on an ABI PRISM 310 Genetic Analyzer. After sequencing analysis using the BigDye terminator method, the paternally originated alleles of the two children were found in one case to show one repeat insertion and in the other case one repeat deletion as compared with each father. Although the number of meioses observed in this study is limited, it appears that ACTBP2 mutations are not rare events in the Japanese population.

Journal Article↗
PubMed2000

Development of chitosan-magnetite aggregates containing Nitrosomonas europaea cells for nitrification enhancement.

A cell suspension of the nitrifying bacterium Nitrosomonas europaea obtained after 96-h cultivation was subjected to magnetic separation using chitosan-conjugated magnetite particles (chitosan-magnetite), which have the ability to form aggregates with microbial cells. An equilibrium condition was obtained at room temperature after 30 min and over 90% of the cells were recovered when the chitosan-magnetite concentration was 200 mg/l. The relationship between the cell concentration in the supernatant in equilibrium and the number of cells adsorbed per 1g chitosan-magnetite was expressed by a Freundlich-type adsorption equation. A high nitrifying bacterium activity yield was obtained with a chitosan-magnetite concentration between 100 and 200 mg/l. Repeated batch culture resulted in more N. europaea cells accumulating on the aggregates and as a consequence their nitrification activity improved further. The chitosan-magnetite/cell aggregates were recovered and employed to remove ammonia from artificial wastewater together with PVA-alginate gel beads containing the denitrifying bacterium Paracoccus denitrificans. A higher ammonia removal rate was achieved under aerobic conditions in comparison with that obtained when N. europaea and P. denitrificans were coimmobilized in PVA-alginate gel beads.

Journal Article↗
PubMed2000

Sniff nasal inspiratory pressure as a marker of respiratory function in motor neuron disease.

Vital capacity (VC) and maximum mouth pressures are often used to monitor respiratory function in motor neuron disease (MND), but require the use of a mouthpiece. Sniff nasal inspiratory pressure (SNIP) is a simple and reliable means of measuring inspiratory muscle strength; it does not involve the use of a mouthpiece and might therefore be better than VC or mouth pressures for assessing patients with bulbar disease. SNIP, maximum inspiratory (MIP) and expiratory mouth pressure (MEP), VC and arterial carbon dioxide tension (Pa,CO2) were measured in 59 consecutive patients attending a specialist MND clinic. Thirty-one had bulbar involvement on clinical grounds. Both SNIP and VC were inversely related to Pa,CO2 in nonbulbar patients only. Neither MIP nor MEP were related to Pa,CO2. The 10 patients with an elevated Pa,CO2 (>6 kPa) had significantly lower SNIP and VC than normocapnic patients. Sniff nasal inspiratory pressure can be used to monitor respiratory function in motor neuron disease. It is quick and easy for patients to perform, but otherwise appears to offer little advantage over vital capacity measurement. Patients with bulbar disease are often poor at performing sniff nasal inspiratory pressure manoeuvres, possibly because of upper airway collapse or inability to close the mouth completely during the manoeuvre.

Female↗
PubMed2000

Ribozyme-mediated suppression of platelet type 12 lipoxygenase in human erythroleukemia cells.

The platelet type 12 lipoxygenase (12-LOX) adds molecular oxygen to C-12 arachidonic acid to yield 12-hydroperoxy-5,8,10,14-eicosatetraenoic acid. It has been suggested that 12-LOX and its metabolites play an important role in tumor angiogenesis. A hammerhead ribozyme (Rz) targeted to the first GUC site within the 12-LOX mRNA was designed and cloned into an in vitro transcriptional or mammalian expression vector. In vitro, the Rz was able to cleave its substrate efficiently in a time-dependent manner. Under multiple turnover conditions, the Rz performed well at 37 degrees C, with a further improvement at 50 degrees C. When cloned into a mammalian expression vector, pSV2neo, the Rz construct efficiently decreased the level of 12-LOX mRNA in stably transfected human erythroleukemia cells to levels that were undetectable by Northern blot analyses. 12-LOX enzyme activity assays showed that Rz significantly reduced the 12-hydroperoxy-5,8,10,14-eicosatetraenoic acid production in human erythroleukemia cells; this effect was sustained for up to 6 months in cell culture. The Rz developed in this study may represent a powerful tool for potential applications, ranging from an understanding of tumor angiogenesis to cancer gene therapy.

Arachidonate 12-Lipoxygenase↗
PubMed2000

Anaesthetic implications of osteo-odonto-keratoprosthesis surgery.

Patients with bilateral corneal blindness in whom corneal transplantation has either been unsuccessful or inappropriate may be considered for osteo-odonto-keratoprosthesis surgery. During a two-stage procedure the surface of the cornea is removed and covered with a graft of buccal mucosa. An optical cylinder, supported by an osteo-odonto lamina planed from a tooth is then inserted into the mucosa to act as a lens. The anaesthetic implications of this operation include care of patients from a wide age range, often with underlying medical problems undergoing two operations of prolonged duration. The eye can be 'open' during both stages of the operation and anaesthetic techniques directed towards prevention of rises in vitreal pressure are essential. This article outlines the surgical process of osteo-odonto-keratoprosthesis surgery with reference to our anaesthetic experiences from nine cases.

Adult↗
PubMed2000

Transmission electron microscopy of semiconductor quantum dots

We report on plan-view transmission electron microscopy techniques, by which the size, the actual shape and the strain of a coherent quantum dot in semiconductor heterostuctures can be measured very accurately. The bright-field suppressed-diffraction imaging condition where no strong diffracted beam is excited in the sample provides reliable size measurement. Using suppressed-diffraction imaging condition, the intensity contour in a coherent island is related to the height, and thus the detailed shape and the aspect ratio can be extracted. The strain contrast of a coherent island imaged using an exact two-beam dynamical diffraction condition is useful for strain measurement and the corresponding features is related to the shape of an island. The physical origins and accuracy of interpretation of the image contrast are discussed, using the simulations and experimental examples.

Journal Article↗
PubMed2000

Application of short tandem repeat of genomic DNA and mitochondrial DNA for identification of mixed-up tissue specimens.

Deoxyribonucleic acid (DNA) typing methods, short tandem repeat of genomic DNA and mitochondrial DNA with the use of polymerase chain reaction amplification, were applied to formalin-fixed, paraffin-embedded tissues submitted for diagnosis, to identify and sort out mixed-up tissue specimens. These techniques were found to be reliable, reproducible and specific for personal identification, and thus to eliminate the need for further examinations and to prevent unnecessary surgery.

Aged↗
PubMed2000

Expression of fas ligand on bile ductule epithelium in biliary atresia--a poor prognostic factor.

PURPOSE: The aim of this study was to investigate the possible role of Fas and Fas ligand system in biliary atresia. METHODS: Immunohistochemical stains of Fas and Fas ligand (FasL) and in situ hybridization of Fas ligand messenger RNA (mRNA) were performed on paraffin-embedded liver specimens of 36 biliary atresia, 6 choledochal cysts, and 14 nontumorous parts of pediatric liver tumors. Apoptosis was detected by terminal deoxynucleotidyl transferase deoxy-UTP nick end labeling (TUNEL). The grade of liver fibrosis and results of bile drainage on the patients with biliary atresia were compared with the results of FasL expression. RESULTS: Fas protein was positive on the hepatocytes and bile ductule epithelia of all the livers examined and also positive on some monocytes around the portal area in all the biliary atresia patients. FasL protein was positive on bile ductule epithelia in 10 biliary atresia patients and also positive on some monocytes in most of the biliary atresia patients. Positive signals of FasL mRNA were noted on hepatocytes in 4 biliary atresia, bile ductule epithelia in 19 biliary atresia patients, and some monocytes in most of the biliary atresia patients. Apoptotic nuclei were present among monocytes in all the biliary atresia livers but present among bile ductule epithelia only on the BA with positive FasL mRNA signals on ductule epithelium. The fibrosis grade was similar between biliary atresia with positive FasL mRNA signals and negative signals. The bile drainage was better in the biliary atresia without positive FasL mRNA signals. CONCLUSIONS: Fas ligand expression on bile ductule epithelia in biliary atresia may be induced to counterattack the infiltrating lymphocytes. Although the factors for post-Kasai bile drainage are multiple, the authors suggest Fas ligand expression on bile ductule epithelia may be a poor prognostic factor by playing a role in the continuous damage and obliteration of intrahepatic bile ducts after Kasai operation.

Base Sequence↗
PubMed2000

Reconstruction of the Achilles tendon and overlying soft tissue using antero-lateral thigh free flap.

Reconstruction of combined loss of the Achilles tendon and overlying soft tissue was performed using an antero-lateral thigh free flap in three patients. The cutaneous portion is used to cover the open wound, and a piece of fascia lata is utilised to replace the missing segment of the Achilles tendon. The skin defect ranged from 5 x 2.5 to 7 x 5 cm, and the tendon loss measured from 3.5 to 5.5 cm in length. All of the patients showed satisfactory functional results with a follow-up period from 3 to 9 months. The advantages of the procedure are that: it is a single-staged operation; it promotes rapid healing of the tendo Achilles since the tendon substitute is well vascularised; it is adaptable to a wide range of defect sizes and shapes; it can be performed in the supine position without the need for postural change; and it can restore good contour and causes minimal morbidity at the donor site.

Achilles Tendon↗