Biomedical subjects

X Fu

Publications and source records attributed to X Fu.

At least 55 records · Page 3Linked to original sources

PubMed2001

[Accelerated hyperfractionation radiation therapy combined with chemotherapy for non-small cell lung cancer complicated with superior vena cava syndrome].

OBJECTIVE: This retrospective study was done to evaluate the patient's tolerance and effect of accelerated hyperfractionation radiation therapy in the treatment of superior vena cava syndrome (SVCS) caused by non-small cell lung cancer (NSCLC). METHODS: Thirty-four NSCLC patients complicated with SVCS were treated between January 1992 and September 1996. Their ages ranged from 36-78 years (median 57). There were 30 (88.2%) male and 4(11.8%) female patients. Dyspnea (67.6%) and facial swelling (52.9%) were the two most common symptoms. Engorgement of neck veins (38.2%) and dilated chest wall veins (28.5%) were the most common physical findings. According to their pathological diagnosis, there were 17(50%) squamous cell carcinomas, 14(41.2%) adenocarcinomas, 2(5.9%) mixed squamous and adenocarcinomas and 1(2.96%) poorly differentiated carcinomas. By thoracic CT scans, a mass was most commonly found in the right upper lobe and the upper mediastinum. For these patients, chemotherapy IEP or IAP (IFO 2.0 g d1-4, DDP 40 mg d1-3, Vp-16 0.1 g d1-3 or ADM 50 mg d1) was given first. Twenty-four to 72 hours after chemotherapy, accelerated hyperfractionation radiation therapy was started to deliver to the primary tumor and the metastatic mediastinal lymph nodes, a tumor dose of 30 Gy/20 fx/2 wk followed by a boost to 36-40.8 Gy/30-34 fx/3-3.5 wk. Diuretics, steroids and dehydrating agents were concomittantly prescribed during the radiation therapy. RESULTS: Relief of SVCS to various degrees was noted in all patients. CR, PR and MR rates were 20.6% (7/34), 50% (17/34) and 29.4% (10/34), respectively. The median survival was 12 months (4-26 months). The 1-2 year actuarial survival rates were 58.1% and 18.2% Except radio-esophagitis in different degrees, no other severe complications were observed. CONCLUSION: The fraction and total dose of radiotherapy are tolerable in this accelerated hyperfractionation trial. Radiation therapy combined with chemotherapy gives similar results as non-surgery for stage III NSCLC. No significant difference in the survival rates of the various histological types is observed.

Adenocarcinoma↗

PubMed2001

[Clinical study of P-gp, and bcl-2 protein expression in non-Hodgkin's lymphomas patients].

OBJECTIVE: To investigate the relationship between the expression of P-gp, P26-bcl-2 and the prognosis in intermediate and high grade non-Hodgkin's lymphomas (NHL). METHODS: Sixty cases of intermediate and high grade NHL were retrospectively reviewed using immunohistochemical method. All patients were received CHOP chemotherapy over 4 courses. RESULTS: P-gp was identified in 15 and P26-bcl-2 in 25 cases. The 3-year survival rates for patients with P26-bcl-2 (+) and P26-bcl-2 (-) were 37.64% and 76.80%, respectively (P < 0.005), and for patients with both positive P-gp and P26-bcl-2 and both negative were 15.38% and 48.48%, respectively (P = 0.038). CONCLUSIONS: There is direct relationship between the P-gp, P26-bcl-2 protein expression and the prognosis in intermediate and high grade non-Hodgkin's lymphoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[Spectrum studies on titania photocatalysts].

The nano-sized TiO2 photocatalysts were prepared by sol-gel method and characterized by FTIR spectroscopy, FT-Raman spectroscopy and diffuse reflectance spectroscopy(DRS). Photocatalytic degradation of oleic acid over the TiO2 catalysts was investigated. The result showed that calcination temperature has strong effect on crystal structure, energy band structure, optical adsorption and photocatalytic activity of the TiO2 catalysts. It was found that the TiO2 photocatalyst calcined at 400 degrees C has the best apparent optical adsorption, the biggest band edge position and the highest photoactivity. The effect of calcination temperature on photocatalytic activity of TiO2 catalysts has been ascribed to the changes in structure and optical property of catalyst such as crystal size, content of rutile, residual NO3-, and band-edge position of light adsorption.

Adsorption↗

PubMed2000

Temporalis exteroceptive suppression in generalized anxiety disorder and major depression.

The duration abnormality of the exteroceptive suppressions, or silent periods, of peripheral or jaw-closing muscle activities induced by transcranial magnetic or trigeminal electrical stimuli in patients suffering from anxiety or depression is ill-defined. We therefore studied the exteroceptive suppression periods of the temporalis muscle electromyography elicited by trigeminal territory electrical stimuli, Zuckerman-Kuhlman's Personality Questionnaire, and Plutchik-van Praag's Depression Inventory (PVP) in 12 patients suffering from generalized anxiety disorder (GAD) and 16 from major depression (MD) as well as in 17 healthy volunteers. Durations of the second suppression period (ES2) sociability scores were decreased in GAD patients, while PVP and neuroticism-anxiety scores were elevated in both GAD and MD patients. There was a positive correlation between ES2 duration and sociability score in the GAD group. This study indicates that anxiety can modify the temporalis ES2 duration through cortical descending inhibitory controls.

Adolescent↗

PubMed2000

Gas chromatography-mass spectrometry with tert.-butyldimethylsilyl derivation: use of the simplified sample preparations and the automated data system to screen for organic acidemias.

A simplified, sensitive screening method for organic acidemias by gas chromatography-mass spectrometry using urease/direct preparations and tert.-butyldimethylsilylation (TBDMS) instead of trimethylsilylation (TMS) is described. We compiled GC-MS data on TBDMS derivatives, including methylene unit values, and quantifying and confirming ions, for use in the automated data system we developed. Quantification using [M-57]+ ions by mass chromatography was more sensitive, and the coefficient variation was smaller, compared with TMS derivatives. We confirmed the usefulness of this system, analyzing urine specimens from 53 patients with 15 different disorders.

Acids↗

PubMed2000

Folding pathway mediated by an intramolecular chaperone. The inhibitory and chaperone functions of the subtilisin propeptide are not obligatorily linked.

The subtilisin propeptide functions as an intramolecular chaperone (IMC) that facilitates correct folding of the catalytic domain while acting like a competitive inhibitor of proteolytic activity. Upon completion of folding, subtilisin initiates IMC degradation to complete precursor maturation. Existing data suggest that the chaperone and inhibitory functions of the subtilisin IMC domain are interdependent during folding. Based on x-ray structure of the IMC-subtilisin complex, we introduce a point mutation (E112A) to disrupt three hydrogen bonds that stabilize the interface between the protease and its IMC domain. This mutation within subtilisin does not alter the folding kinetics but dramatically slows down autoprocessing of the IMC domain. Inhibition of E112A-subtilisin activity by the IMC added in trans is 35-fold weaker than wild-type subtilisin. Although the IMC domain displays substantial loss of inhibitory function, its ability to chaperone E112A-subtilisin folding remains intact. Our results show that (i) the chaperone activity of the IMC domain is not obligatorily linked with its ability to bind with and inhibit active subtilisin; (ii) degradation and not autoprocessing of the IMC domain is the rate-limiting step in precursor maturation; and (iii) the Glu(112) residue within the IMC-subtilisin interface is not crucial for initiating folding but is important in maintaining the IMC structure capable of binding subtilisin.

Catalysis↗

PubMed2000

Alternative silencing effects involve distinct types of non-spreading cytosine methylation at a three-gene, single-copy transgenic locus in rice.

We investigated transgene silencing in a line of rice plants that carries a single-copy 6.6-kb transgenic locus comprising three heterologous transgenes: bar, hpt and gusA. We identified at least three distinct types of silencing effects associated with different methylation patterns, including a novel form of transcriptional silencing involving methylation of cytosine residues only at non-conventional acceptor sites in the coding region. Silencing arose de novo in individual R1, R2 and R3 plants despite the stability of the transgenic locus, although the basic structure of the locus, transgene dosage and position effects remained constant within the line. We found that different silencing effects could occur concurrently in adjacent heterologous transgenes in the same plant, with no evidence for spreading of silenced states or methylation patterns from one transgene to another.

Base Sequence↗

PubMed2000

Presence and localization of connexins 43 and 26 in cell cultures derived from myometrial tissues from nonpregnant and pregnant women and from leiomyomas.

OBJECTIVE: Our objective was to study the appearance and distribution of connexins 43 and 26 in various human myometrial cell cultures. STUDY DESIGN: Scrape loading, Western blotting, and immunohistochemical techniques were applied to cultured cells derived from myometrial tissues obtained from nonpregnant and pregnant women (upper and lower uterine segments) and from leiomyomas (tumor and analogous myometrial tissues). RESULTS: Scrape loading revealed the presence of metabolic coupling in all tissues. Indirect immunohistochemical studies showed membrane localization of connexin 43 in all myometrial cultures. Western blots and indirect immunohistochemical studies showed the presence and localization of the connexin 26 protein and associated gap junctions in tissues from myomas and from nonpregnant and pregnant women except for those derived from the upper segment of the pregnant uterus. CONCLUSION: These results show that human myometrial cultures express various gap junction proteins and that there are regional differences in expression of connexins in tissues from pregnant women.

Blotting, Western↗

PubMed2000

Simplified screening for organic acidemia using GC/MS and dried urine filter paper: a study on neonatal mass screening.

A simplified method for organic acidemia screening using GC/MS, the urease/direct method, is now available. To establish a practical screening system for organic acidemias, we studied the usefulness of dried urine filter paper (filter paper urine) and the application of a personal computer-based system of automated metabolic profiling and interpretation (automated system) that we earlier developed. In a comparison of filter paper urine with liquid urine, creatinine levels ranging from 4.6 to 122.5 mg/dl, showed an excellent correlation (r=0.9554), when the volumes of blotted urine and distilled water soaked were the same. Recovery of all 17 compounds except for citrate was similar between liquid and filter paper urine. CV values of 22 compounds tested ranged from 5.5 to 22.4% in the liquid urine, and from 7.7 to 29.8% in the filter paper urine. The CV values in stable isotope dilution analysis were much smaller in all nine compounds tested. As to the stability of compounds, the percentage changes to values at day 0 were within about +/-25% on day 28. We compiled GC/MS data, including methylene unit values, quantifying and confirming ions of 163 different organic acids and others, to use the automated system. We analyzed specimens from 55 patients with 17 different metabolic disorders. In 54 of the 55 specimens, the correct diagnosis was successfully indicated. Neonatal mass screening for organic acidemias warrants ongoing attention using this simplified method and filter paper urine.

Acidosis↗

PubMed2000

Equilibrium modeling of 5-HT(2A) receptors with [18F]deuteroaltanserin and PET: feasibility of a constant infusion paradigm.

[(18)F]Altanserin has emerged as a promising positron emission tomography (PET) ligand for serotonin-2A (5-HT(2A)) receptors. The deuterium substitution of both of the 2'-hydrogens of altanserin ([(18)F]deuteroaltanserin) yields a metabolically more stable radiotracer with higher ratios of parent tracer to radiometabolites and increased specific brain uptake than [(18)F]altanserin. The slower metabolism of the deuterated analog might preclude the possibility of achieving stable plasma and brain activities with a bolus plus constant infusion within a reasonable time frame for an (18)F-labeled tracer (T(1/2) 110 min). Thus, the purpose of this study was to test the feasibility in human subjects of a constant infusion paradigm for equilibrium modeling of [(18)F]deuteroaltanserin with PET. Seven healthy male subjects were injected with [(18)F]deuteroaltanserin as a bolus plus constant infusion lasting 10 h postinjection. PET acquisitions and venous blood sampling were performed throughout the infusion period. Linear regression analysis revealed that time-activity curves for both specific brain uptake and plasma [(18)F]deuteroaltanserin concentration stabilized after about 5 h. This permitted equilibrium modeling and estimation of V(')(3) (ratio of specific uptake to total plasma parent concentration) and the binding potential V(3) (ratio of specific uptake to free plasma parent concentration). Cortical/cerebellar ratios were increased by 26% relative to those we previously observed with [(18)F]altanserin using similar methodology in a somewhat older subject sample. These results demonstrate feasibility of equilibrium imaging with [(18)F]deuteroaltanserin and suggest that it may be superior to [(18)F]altanserin as a PET radioligand.

Adolescent↗

PubMed2000

Linear transgene constructs lacking vector backbone sequences generate low-copy-number transgenic plants with simple integration patterns.

Whole plasmids are used in both Agrobacterium-mediated transformation and direct DNA transfer, generally leading to the integration of vector backbone sequences into the host genome along with the transgene(s). This is undesirable, as vector backbone sequences often have negative effects on transgene or endogenous gene expression, and can promote transgene rearrangements. We, therefore, bombarded rice tissue with two constructs: a plasmid containing the bar gene, and a linear DNA fragment isolated from the same plasmid, corresponding to the minimal bar gene expression cassette (promoter, open reading frame and terminator). We recovered phosphinothricin-resistant plants from both experiments, showing that the selectable marker was efficiently expressed. Transformation with such constructs resulted in predominantly 'simple' integration events (one or two bands on Southern blots), producing low-copy-number transgenic plants with a low frequency of transgene rearrangements. Conversely, transformation with supercoiled or linearized whole plasmids generated plants with 'complex' integration patterns, that is, higher copy numbers and frequent transgene rearrangements. We monitored transgenic lines through to the R4 generation and observed no silencing in plants carrying minimal constructs. We also carried out experiments in which rice tissue was simultaneously bombarded with minimal linear hpt and gusA cassettes. We observed robust GUS activity in hygromycin-resistant plants, confirming co-expression of the selectable and nonselectable markers. Furthermore, the efficiency of cotransformation using minimal constructs was the same as that using supercoiled plasmid cointegrate vectors.

Acetyltransferases↗

PubMed2000

Prostaglandin F2alpha-induced Ca++ oscillations in human myometrial cells and the role of RU 486.

OBJECTIVE: We sought to examine the change of cytosolic calcium concentration caused by prostaglandin F(2)(alpha) and RU 486 in cultured human myometrial cells. STUDY DESIGN: Human myometrial cells obtained from 16 nonpregnant women were loaded with fura 2, and the intracellular cytosolic calcium concentrations were measured by the use of wavelength spectrophotofluorometry. RESULTS: Application of prostaglandin F(2)(alpha) (2.8 micromol/L) caused an initial rapid rise in cytosolic calcium concentration followed by sustained cytosolic calcium oscillations at an average frequency of 0.43 +/- 0.04 min(-1) and an amplitude in the range of 296.82 +/- 27. 16 nmol/L. The oscillatory activity was not affected by increasing the concentration of prostaglandin F(2)(alpha) but varied by changing the concentration of extracellular cytosolic calcium concentration. The cytosolic calcium oscillations were suppressed by caffeine, 2,5-di-tert-butylhydroquinone, and lanthanum but not affected by ryanodine. Verapamil decreased the amplitude but not the frequency of oscillations. The progesterone antagonist RU 486 at a concentration of 10(-8) to 10(-5) mol/L had no significant effect on the basal intracellular cytosolic calcium. However, RU 486 (10(-5) mol/L) significantly increased the frequency but not the amplitude of intracellular cytosolic calcium oscillations induced by prostaglandin F(2)(alpha). CONCLUSION: The results indicate that prostaglandin F(2)(alpha)-stimulated cytosolic calcium oscillations are mediated by an increase in both cytosolic calcium release from inositol 1,4,5-trisphosphate-sensitive cytosolic calcium stores and a cytosolic calcium influx from the extracellular space. Moreover, RU 486 seems to directly regulate prostaglandin F(2)(alpha)-induced intracellular cytosolic calcium in human myometrial cells.

Adult↗

PubMed2000

Color Doppler flow imaging of the facial artery and vein.

The purpose of this study was to provide some guidelines with respect to the location of the facial vessels, display the potential inverted blood flow of the facial artery, and reemphasize the value of color Doppler ultrasound studies in flap planning. An anatomic study of the facial artery and vein was done using color Doppler ultrasonography in 12 adults. The artery and the vein were located together at the lower border of the mandible. Around the oral commissure and under the nasal ala, they were located apart from each other with variable distances. This divergence of the facial vein from the artery is important information in the planning of axial pattern flaps. Furthermore, the reverse flow was observed in 12 patients after the blood flow of the facial artery was stopped by applying pressure manually at the lower border of the mandible. Observation of the reversed flow confirms the possibility of safe elevation of a retrograde flow-arterialized flap based on the distal portion of the facial artery.

Adolescent↗

PubMed2000

Development of a chromosome-plasmid balanced lethal system for Lactobacillus acidophilus with thyA gene as selective marker.

A chromosome-plasmid balanced lethal gene delivery system for Lactobacillus acidophilus based on the thyA gene was developed. The selected L. acidophilus DOM La strain carries a mutated thyA gene and has an obligate requirement for thymidine. This strain can be used as a host for the constructed shuttle vector pFXL03, lacking antibiotic-resistant markers but having the wild-type thyA gene from L. casei which complements the thyA chromosomal mutation. The vector also contains the replicon region from plasmid pUC19 and that of the Lactococcus plasmid pWV01, which allows the transfer between Escherichia coli, L. casei and L. acidophilus. Eight unique restriction sites (i.e., PstI, HindIII, SphI, SalI, AccI, XbaI, KpnI and SacI) are available for cloning. After 40-time transfers in modified MRS medium, no plasmid loss was observed. The vector pFXL03 is potentially useful as a food-grade vaccine delivery system for L. acidophilus.

Drug Delivery Systems↗

PubMed2000

Membrane redistribution of the Escherichia coli MinD protein induced by MinE.

Escherichia coli cells contain potential division sites at midcell and adjacent to the cell poles. Selection of the correct division site at midcell is controlled by three proteins: MinC, MinD, and MinE. It has previously been shown (D. Raskin and P. de Boer, Cell 91:685-694, 1997) that MinE-Gfp localizes to the midcell site in an MinD-dependent manner. We use here Gfp-MinD to show that MinD associates with the membrane around the entire periphery of the cell in the absence of the other Min proteins and that MinE is capable of altering the membrane distribution pattern of Gfp-MinD. Studies with the isolated N-terminal and C-terminal MinE domains indicated different roles for the two MinE domains in the redistribution of membrane-associated MinD.

Adenosine Triphosphatases↗

PubMed2000

Agricultural work-related injuries among farmers in Hubei, People's Republic of China.

OBJECTIVES: This population-based study evaluated patterns of and risk factors for, agricultural injuries among farmers in the People's Republic of China. METHODS: A multistage sample of 1500 Chinese farmers was selected from 14 villages. Face-to-face interviews with 1358 farmers were conducted between July 1997 and September 1997 (response rate = 91%). Agricultural work-related injuries that occurred in the previous 24 months and the associated factors were evaluated. RESULTS: A total of 33% of the farmers reported at least 1 work-related injury in the 24 months before the survey. Major external causes of the injuries were hand tools (50%), falls (26%), and heavy falling objects (10%). The statistically significant risk factors for injury were low family income, 1 to 6 school years of education, self-reported pesticide exposure, tension in relationships with neighbors, and stress in life. The most notable result was the relation between self-reported pesticide exposure and injury, with farmers with greater pesticide exposure at significantly greater risk for injury. CONCLUSIONS: The results of this study indicated that injuries occurring among Chinese farmers may have unique patterns and potential risk factors.

Accidents, Occupational↗

PubMed2000

Oxytocin-induced oscillations of cytoplasmic Ca2+ in human myometrial cells.

BACKGROUND: To investigate the mechanisms of oxytocin (OT) induced oscillations of the cytoplasmic Ca2+ concentration ([Ca2+]i) in cultured human myometrial cells. METHODS: [Ca2+]i was measured in individual myometrial cells by dual wavelength spectrophotofluorometry using the fluorescent indicator fura-2. Myometrium was obtained at abdominal hysterectomy (n=8) and during cesarean section (n=7). RESULTS: OT (10-300 nM) typically induced [Ca2+]i oscillations with frequencies in the 0.6-0.8/min range. There were no obvious differences in the responses of cells taken from non-pregnant and term pregnant women. The frequency and amplitude of the oscillations were not significantly affected by OT concentrations up to 300 nM. The amplitude of the oscillations decreased in the presence of the voltage-dependent Ca2+ channel antagonist verapamil and gradually disappeared in Ca2+-free medium. The oscillations were further blocked by the inorganic Ca2+ antagonist La3+ and by the intracellular Ca2+-ATPase inhibitor 2.5-di-tert-butylhydroquinone (DTBHQ). Caffeine inhibited the OT-induced oscillations in a concentration-dependent manner. DTBHQ and high concentrations of OT made [Ca2+]i remarkably sensitive to changes in the external Ca2+ concentration. CONCLUSIONS: The results indicate that OT-induced [Ca2+]i oscillations in human myometrial cells are due to inositol 1,4,5-trisphosphate-mediated release of intracellular Ca2+ combined with capacitative as well as voltage-dependent influx of the ion.

Calcium Signaling↗

PubMed2000

[A system of microcomputer analysis for biological oxygen consumption and its application].

This paper introduces a microcomputer system of data analysis and methods of measuring oxygen consumption for biological materials. The system overcame some disadvantages of operating inconvenience and difficulties of collective and analytic data by traditional means. The system possesses functions of automatic enactment, collection, save/take and analysis for many experimental data. It can be used to measure oxygen consumption of tissues, cells and mitochondria.

Animals↗