Prospective study on the diagnosis and prognosis of lung cancer by using new simultaneously observed seromarkers.
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Adenocarcinoma↗
Biomedical subjects
Q Zhang
Publications and source records attributed to Q Zhang.
Evidence that His110 of the protein FadL in the outer membrane of Escherichia coli is involved in the binding and uptake of long-chain fatty acids: possible role of this residue in carboxylate binding.
The binding of exogenous fatty acids to the outer-membrane protein FadL of Escherichia coli is specific for long-chain fatty acids (C14-C18). Oleoyl alcohol [(Z)-9-octadecen-1-ol] and methyl oleate were unable to displace FadL-specific binding of [3H]oleate (C18:1), suggesting that the carboxylate of the long-chain fatty acid was required for binding. Therefore the binding of exogenous fatty acids to FadL is governed, in part, by the carboxy group of the long-chain fatty acid. Treatment of whole cells with 1 mM diethyl pyrocarbonate (DEPC) depressed binding by 43-73% over the range of oleate concentrations used (10-500 nM). On the basis of these results and the notion that histidine residues often play a role involving proton transfer and charge-pairing, the five histidine residues within FadL (His110, His226, His327, His345 and His418) were replaced by alanine using site-directed mutagenesis. Altered FadL proteins were correctly localized in the outer membrane at wild-type levels and retained the heat-modifiable property characteristic of the wild-type protein. Initial screening of these fadL mutants revealed that the replacement of His110 by Ala resulted in a decreased growth rate on minimal oleate/agar plates. The rates of long-chain fatty acid transport for delta fadL strains harbouring each mutation on a plasmid, with the exception of fadLH110A, were the same, or nearly the same, as those for the wild-type. fadLH110A was also defective in binding, arguing that the functional effect of this mutation was at the level of long-chain-fatty-acid binding.(ABSTRACT TRUNCATED AT 250 WORDS)
Alanine↗
Essential role for ZAP-70 in both positive and negative selection of thymocytes.
During thymic development, T cells that can recognize foreign antigen in association with self major histocompatibility complex (MHC) are selected for survival (positive selection) and autoreactive T cells are eliminated (negative selection). Both of these selective events are mediated by interaction between the T-cell receptor (TCR) and the peptide-MHC complex. But the signalling pathways that lead to cell survival or to cell death are still unclear. ZAP-70 is a protein tyrosine kinase (PTK) that is associated with the TCR signalling subunits (CD3 and zeta) and is expressed in T cells and natural killer cells. It has been shown that ZAP-70 plays a crucial role in T-cell activation and development. Here we show that mice lacking ZAP-70 had neither CD4 nor CD8 single-positive T cells, but human ZAP-70 reconstituted both CD4 and CD8 single-positive populations. Moreover, ZAP-70-/- thymocytes were not deleted by peptide antigens. Natural killer cell function was intact in the absence of ZAP-70. These data suggest that ZAP-70 is a central signalling molecule during thymic selection for CD4 and CD8 lineage.
Animals↗
Activation of glycine decarboxylase in pea leaf mitochondria by ATP.
Activity of glycine decarboxylase decreased by 60-70% after the isolated pea leaf mitochondria were aged for 5 h in the absence of glycine and was completely lost after 24 h. The reverse reaction, i.e., production of glycine from serine, ammonium, dihydrolipoate, and bicarbonate, was also inhibited in these aged mitochondria. Glycine decarboxylase could be reactivated by both exogenous and endogenous ATP. The latter was formed during the oxidation of succinate, malate, or oxoglutarate. Glycine decarboxylase consists of four subunits (P-, H-, L-, and T-proteins). The aged mitochondria were able to catalyze the exchange of [14C]-bicarbonate-glycine and the oxidation of dihydrolipoate, indicating the persistence of P-, H-, and L-protein activities. Serine hydroxymethyltransferase catalyzes the formation of serine from methylene tetrahydrofolate and another glycine and molecule at the last reaction of glycine oxidation. The aged mitochondria were able to catalyze the formation of methylene tetrahydrofolate from [14C]serine and its reverse reaction. Therefore, it was concluded that the loss of glycine decarboxylase activity was due to an inhibition of the reaction catalyzed by T-protein, which required ATP for its activation.
Adenosine Triphosphate↗
Transcriptional activation of human adult alpha-globin genes by hypersensitive site-40 enhancer: function of nuclear factor-binding motifs occupied in erythroid cells.
The developmental stage- and erythroid lineage-specific activation of the human embryonic zeta- and fetal/adult alpha-globin genes is controlled by an upstream regulatory element [hypersensitive site (HS)-40] with locus control region properties, a process mediated by multiple nuclear factor-DNA complexes. In vitro DNase I protection experiments of the two G+C-rich, adult alpha-globin promoters have revealed a number of binding sites for nuclear factors that are common to HeLa and K-562 extracts. However, genomic footprinting analysis has demonstrated that only a subset of these sites, clustered between -130 and +1, is occupied in an erythroid tissue-specific manner. The function of these in vivo-occupied motifs of the alpha-globin promoters, as well as those previously mapped in the HS-40 region, is assayed by site-directed mutagenesis and transient expression in embryonic/fetal erythroid K-562 cells. These studies, together with our expression data on the human embryonic zeta-globin promoter, provide a comprehensive view of the functional roles of individual nuclear factor-DNA complexes in the final stages of transcriptional activation of the human alpha-like globin promoters by the HS-40 element.
Adult↗
Ab initio studies of the diffusion barriers at single-height Si(100) steps.
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Journal Article↗
Effect of growth factors on substance P mRNA expression in axotomized dorsal root ganglia.
The effects of NGF, BDNF, NT-3, BDNF plus NT-3 and LIF on substance P (SP) mRNA levels were analysed in axotomized dorsal root ganglia (DRGs) in vivo by quantitative in situ hybridization. The growth factors were applied on to the transected sciatic nerve. SP mRNA levels were decreased significantly 3 days after axotomy. NGF (1 microgram) fully counteracted the down-regulation of SP mRNA. Neither BDNF (10 micrograms) nor NT-3 (10 micrograms) alone had any effect. However, co-administration of BDNF together with NT-3 (10 micrograms) distinctly reversed the decrease in SP mRNA. A similar effect was seen with a high (1.5 micrograms) but not a low dose of LIF (0.15 microgram). Our data suggest that the present method of delivering growth factors to the transected sciatic nerve is a valid way to study in vivo effects of growth factors on peptide expression in DRGs. Moreover, SP expression is regulated by several growth factors in vivo such as NGF, BDNF plus NT-3 as well as the neuroimmune factor LIF.
Animals↗
Functional roles of in vivo footprinted DNA motifs within an alpha-globin enhancer. Erythroid lineage and developmental stage specificities.
Transcriptional regulation of the human alpha-like globin genes, embryonic zeta 2 and adult alpha, during erythroid development is mediated by a distal enhancer, HS-40. Previous protein-DNA binding studies have shown that HS-40 consists of multiple nuclear factor binding motifs that are occupied in vivo in an erythroid lineage- and developmental stage-specific manner. We have systematically analyzed the functional roles of these factor binding motifs of HS-40 by site-directed mutagenesis and transient expression assay in erythroid cell cultures. Three of these HS-40 enhancer motifs, 5'NF-E2/AP1, GT II, and GATA-1(c), positively regulate the zeta 2-globin promoter activity in embryonic/fetal erythroid K562 cells and the adult alpha-globin promoter activity in adult erythroid MEL cells. On the other hand, the 3'NF-E2/AP1 motif is able to exert both positive and negative regulatory effects on the zeta 2-globin promoter activity in K562 cells, and this dual function appears to be modulated through differential binding of the ubiquitous AP1 factors and the erythroid-enriched NF-E2 factor. Mutation in the GATA-1(d) motif, which exhibits an adult erythroid-specific genomic footprint, decreases the HS-40 enhancer function in dimethyl sulfoxide-induced MEL cells but not in K562 cells. These studies have defined the regulatory roles of the different HS-40 motifs. The remarkable correlation between genomic footprinting data and the mutagenesis results also suggests that the erythroid lineage- and developmental stage-specific regulation of human alpha-like globin promoters is indeed modulated by stable binding of specific nuclear factors in vivo.
Adult↗
Massive cell death of immature hematopoietic cells and neurons in Bcl-x-deficient mice.
bcl-x is a member of the bcl-2 gene family, which may regulate programmed cell death. Mice were generated that lacked Bcl-x. The Bcl-x-deficient mice died around embryonic day 13. Extensive apoptotic cell death was evident in postmitotic immature neurons of the developing brain, spinal cord, and dorsal root ganglia. Hematopoietic cells in the liver were also apoptotic. Analyses of bcl-x double-knockout chimeric mice showed that the maturation of Bcl-x-deficient lymphocytes was diminished. The life-span of immature lymphocytes, but not mature lymphocytes, was shortened. Thus, Bcl-x functions to support the viability of immature cells during the development of the nervous and hematopoietic systems.
Animals↗
Calnexin recognizes carbohydrate and protein determinants of class I major histocompatibility complex molecules.
Proper folding of nascent polypeptides is essential for their function and is monitored by intracellular "quality control" elements. The molecular chaperone calnexin participates in this process by retaining in the endoplasmic reticulum a variety of unfolded proteins, including class I major histocompatibility complex molecules. We transfected human B cell lines with genes encoding either wild-type HLA-A2 heavy chains or mutant heavy chains lacking sites for glycosylation or deficient in binding to beta 2-microglobulin (beta 2m). In CIR cells, calnexin did not associate detectably with wild-type heavy chains but bound strongly to mutant heavy chains unable to bind beta 2m. Removal of the glycosylation addition site by further mutagenesis prevented binding of mutant heavy chains to calnexin. In Daudi cells, deficient in synthesis of beta 2m, wild-type HLA-A2 heavy chains, but not a non-glycosylated mutant, bound calnexin. Castanospermine, which blocks trimming of glucose residues from asparagine-linked glycans, inhibited association of calnexin with heavy chains encoded by a second class I gene, HLA-B*0702. Although initiation of calnexin binding appears to depend on the presence of oligosaccharide on the substrate, removal of the glycan from calnexin-associated heavy chains by digestion with endoglycosidase H did not disrupt the interaction. These results suggest that calnexin first recognizes carbohydrate on substrate proteins and then binds more stably to peptide determinants, which disappear upon folding.
Calcium-Binding Proteins↗
Photobleaching of light-induced paramagnetic defects in fast and slow processes in a-Si1-xNx:H alloys.
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Journal Article↗
Temperature-modulated incidence of aflatoxin B1-initiated liver cancer in rainbow trout.
Rainbow trout (initial weight of 4 or 5 g) were acclimated at a cool, 11.0 degrees C (C), a warm, 18.0 degrees C (W), or an intermediate temperature 14.5 degrees C (I) for 1 month. There was a slight difference in hepatic microsomal content of one of six cytochrome P450 isozymes between acclimation groups. Monounsaturated fatty acids in hepatic phosphotidylethanolamine but not phosphotidylcholine increased at lower acclimation temperatures. Saturated fatty acid content decreased with temperature for both phospholipid classes. Fish were exposed to 0.08-0.12 ppm waterborne aflatoxin B1 (AFB1) for 30 min at respective acclimation temperatures or after acute temperature shifts (24 hr) and reared for 9 months at C, I, or W. With exposure concentrations which delivered equivalent target organ doses, trout acclimated, exposed, and reared at C, I, or W had liver tumor incidences of 4, 35, and 61%, respectively. The average number of tumors per liver increased from 1.25-1.34 at C to 2.46-2.66 at W. There were no temperature-dependent differences in tumor diameter. When C- and W-acclimated fish were AFB1 exposed and reared at I, tumor incidence was 12.5% for W-I-shifted fish and 26.5% for C-I-shifted fish. This was consistent with previous work which demonstrated acute downward temperature shift reduced [3H]AFB1 adduction to hepatic DNA. Tumor incidence and multiplicity data suggested manipulation of temperature permitted selective modulation of cancer initiation and promotion in rainbow trout.
Aflatoxin B1↗
A hybrid-hybrid matrix method for 3D NOE-NOE data analysis.
A hybrid-hybrid matrix method is described that quantitatively analyzes 3D NOE-NOE NMR data. Experimental 3D data are merged with simulated 3D data to create a hybrid 3D NOE-NOE spectrum. This is then deconvoluted into a 2D hybrid NOESY spectrum. The deconvoluted, 2D hybrid NOESY spectrum can then be merged with other 2D NOESY experimental data along with additional simulated 2D data as necessary to create a hybrid-hybrid 2D NOE volume matrix. This hybrid-hybrid volume matrix is then used with the complete relaxation program, MORASS, to calculate a rate matrix, and the resulting distances taken from the off-diagonal cross-relaxation rates can then be utilized in a distance geometry or restrained molecular-dynamics refinement of the structure. This process is repeated until a satisfactory agreement between the calculated and observed 3D volumes is obtained. This hybrid-hybrid matrix method retains computational efficiency and utilizes the resolution of the 3D data set while retaining any information content of the available 2D data. The initial tests of the deconvolution algorithm give high correlation results even with the introduction of random error into the 3D data set. Our results suggest that the hybrid-hybrid matrix method for analysis of 3D NOE-NOE spectra may provide a viable tool in the refinement of large molecules.
Algorithms↗
Effects of psychophysiological stress on trapezius muscles blood flow and electromyography during static load.
Mental stress was induced by the Stroop colour word task (CW task) and the effects on the microcirculation and electromyography (EMG) in the upper portion of the trapezius muscle were studied during a series of fatiguing, standardized static contractions. A lowered blood flow of the skin recorded continuously by laser-Doppler flowmetry (LDF) was used as a stress indicator in addition to an elevated heart rate. Muscle blood flow was recorded continuously by LDF using a single optical fibre placed inside the muscle, and related to surface EMG. A group of 20 healthy women of different ages was examined. Recordings were made during a 50-min period in the following sequence: a 10-min series of alternating 1-min periods of rest and stepwise increased contraction induced by keeping the arms straight and elevated at 30, 60, 90 and 135 degrees with a 1-kg load carried in each hand; a 10-min recovery period without load; a repeated contraction series with simultaneous performance of the CW task; a second 10-min recovery period, and a second contraction series without CW task. Signal processing was done on line by computer. The LDF and root mean square (rms)-EMG values were calculated, as well as the EMG mean power frequency (MPF) for fatigue. The CW-task added to the contraction series caused an increase in the heart rate accompanied by a decrease in the blood flow to the skin and a 30% increase in the blood flow in the exercising muscle. Both returned to normal during the subsequent recovery period and showed normal levels during the final contraction series without CW. The rms-EMG showed a 20% increase that persisted during the final contraction series performed without CW. There was no influence on MPF. This CW has previously been shown to evoke an increased secretion of adrenaline from the adrenal medullae to the blood. The increased blood flow in the exercising muscle would therefore appear to have been caused by beta-adrenoceptor vasodilatation, and the fall in the blood flow in the skin by alpha-adrenoceptor vasoconstriction. The findings may have implications for work situations characterized by repetitive static loads to the shoulder muscles and psychological stress.
Adult↗
Microcirculation in the upper trapezius muscle during sustained shoulder load in healthy women--an endurance study using percutaneous laser-Doppler flowmetry and surface electromyography.
Microcirculation in the upper portion of the trapezius muscle was measured percutaneously in a group of 16 healthy women of different ages by continuous laser-Doppler flowmetry (LDF) in relation to electromyography (EMG) during an endurance test. During the measurements the subject kept her arms straight and elevated at 45 degrees in the scapular plane and held a 1-kg load in each hand as long as possible. This was followed by rest with the arms hanging and carrying no load. The 10-min recording period comprised 1-min initial rest followed by the endurance test and then recovery. Signal processing was done by computer on line. The LDF and root-mean-square (rms) EMG signals were normalized. Spectrum analyses of EMG mean power frequency (MPF) were performed. The amount of load produced was on average 2,267 (SD 939) N.m.s, i.e. shoulder torque x time expressed as Newton meter seconds, and the endurance time was 4.3 (SD 1.20) min. The rms-EMG as well as the LDF increased significantly during endurance, both when related to endurance time and to amount of load. The MPF showed no significant changes. The mean total increase in muscle blood flow was 175% of that recorded in the initial rest period. The average increase per each 10 s of contraction was 2.9%. Maximum was reached during the 1st min of recovery followed by a fall to the base level that was reached within 77 s on average. The amount of load produced and the blood flow increase was smaller than that found in a separate study of men, indicating a lower functional capacity.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Measurement by laser-Doppler flowmetry of microcirculation in lower leg muscle at different blood fluxes in relation to electromyographically determined contraction and accumulated fatigue.
Single-fibre percutaneous laser-Doppler flowmetry (LDF) of the tibialis anterior muscle was performed continuously for measurement of the microcirculation during different blood fluxes, as well as in relation to different muscle activities and fatigue determined electromyographically (EMG). The laser-Doppler power spectrum density function was studied in a frequency range of 0-8.2 Hz as representing the blood flow most selectively. Reduced blood flow from tourniquet inflation caused a decrease in signal power density, compared to that of intact blood flow at rest. During postocclusion reactive hyperaemia an increased signal power was recorded. This reached its maximum within 4.4 (SD 1.88) s after deflation of the tourniquet. The different fluxes were recorded at high sensitivity and disturbances were small. Periods of 1-min static dorsi-flexion of the foot at 10, 20, 30, 40, and 50% MVC (maximal voluntary contraction) with 1-min rest between were associated with a significant increase in LDF, the recordings obtained during the rest periods showing a tendency towards an increase. A decrease in the EMG mean power frequency (MPF) indicated accumulated fatigue. The LDF for the rest periods that followed upon continuous contractions up to the same MVC levels showed a tendency towards an increase but variability was large. With further development, these techniques may be useful in the evaluation of insufficiency of the peripheral circulation.
Adult↗
Serum biochemical values and mineral element contents of tissues in yaks.
Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.
Animals↗
Improvement of tracheal autograft survival with transplantation into the greater omentum.
BACKGROUND: Reconstruction of tracheal defects with tracheal grafts is not practicable clinically because the problem of tracheal graft revascularization has not been solved successfully. We conducted experiments to investigate efficacy of implanting tracheal graft into the greater omentum for revascularization and possibility of adopting staged transplantation procedure for repair of tracheal defect. METHODS: Twenty-four mongrel dogs were randomly and equally divided into groups I and II. Six-ring cervical tracheal segments were harvested as autografts. The grafts were wrapped with the omentum and placed into the peritoneal cavity in group I, and reimplanted with omentopexy in group II. Four grafts were examined macroscopically, microscopically, and 35S-autoradiographically on postoperative days 3, 7, and 14, respectively. RESULTS: Epithelium loss was evident in the mucosas of the grafts except the 4 from group I. Percentages of viable chondrocytes assessed with 35S-autoradiography were significantly higher in tracheal grafts from group I than group II. All tracheal grafts with their own omental pedicles could be brought to any portions of the trachea. CONCLUSIONS: We conclude that prior implantation of tracheal graft in the omentum is beneficial for preservation of its structure, and reconstruction of a tracheal defect with a tracheal graft implanted first into the omentum is feasible.
Animals↗