[Natural anti-tumor compounds with activity of promoting microtubule assembly].
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Alkaloids↗
Biomedical subjects
L Zhou
Publications and source records attributed to L Zhou.
[The amelioration of electrode techniques for testing cerebral potentials].
This article introduces the research work on the new amelioration of electrode techniques for testing cerebral potentials, and the using methods and their advantages & disadvantages in operating the new cerebral electrode.
Electric Impedance↗
[Determination of cobalt in solidified resin promoter by successive extraction and FAAS].
A new method had been investigated for the analysis of micro-amount of cobalt in solidified resin promoter. Methyl isobutyl ketone (MIBK) was used in 1 mol.L-1 NH4SCN medium followed by 4 mol.L-1 nitric acid back extraction step, then analysis by flame atomic absorption spectrometry. The results indicated that the method was accurate and the interference with concomitant in solidified resin promoter was negligible. The method had a recovery of 96.2%-104.6%.
Carboxylic Acids↗
[Diagnosis and treatment of paragangliomas in the central nerve system].
OBJECTIVE: To explore the diagnosis and treatment of paragangliomas in the central nerve system. METHODS: 17 patients with paragangliomas in the central nerve system over a 20-year period (1976-1999) were analyzed retrospectively. They included 11 patients with glomus jugular tumors, 1 with carotid body tumor, 1 with supersellar paraganglioma, 2 with spinal involvement, and 2 with superficial hemisphere involvement. RESULTS: Neoplasm was completely resected in 11 patients, subtotally in 3, and partial in 3. The postoperative mortality was 1/17. One patient remained severe disability, yet the others had excellent long-time outcome. CONCLUSIONS: Both the characteristic clinical presentation and neuroradiological manifestation were useful for preoperative diagnosis. Total resection is ideal for paragangliomas. Preoperative embolization should be used routinely to control intraoperative bleeding, and postoperative radiation-therapy would be valuable to control the recurrence of the remaining tumor.
Adult↗
[An epidemiological study of spongiform leucoencephalopathy among heorin abusers].
OBJECTIVE: To understand the distribution and related risk factors of heroin spongiform leucoencephalopathy among drug users in coastland of Guangdong Province. METHODS: A cross-sectional study was conducted in four thousand four hundred and twenty eight drug users from eighteen detoxification organizations in six cities on coastland of Guangdong, using clustered random sampling methods. The six cities are Chaoyang (714), Heyuan (462), Shantou (572), Huidong (1286), Guangzhou (871) and Zhanjiang (523) and heroin abuse was considered serious in these cities. Questionnaire was used to collect the data on sex (man 3632, 82 percent; woman 795, 18 percent), age (minimum 15y, maximum 54y), duration of using heroin (minimum 1 month, maximum 150 months), daily dosage (minimum 0.02 g, maximum 6.0 g) and manner of using heroin. In addition, the neurological examination was taken in all of them and cerebral MRI was carried out in those with signs of cerebellar ataxia. RESULTS: Results showed that the total incidence of heroin spongiform leucoencephalopathy in six cities is 3.16 per thousand. Poisson regression analysis showed that the incidence was related to residential areas. In comparison with other cities, there are higher incidences in Chaoyang and Heyuan. Our investigation also showed that all the patients with this disease used heroin by inhaling the pyrolysate. The incidence of heroin spongiform leucoencephalopathy was unrelated to the daily inhaling amount of heroin and the duration of inhaling heroin. No differences could be observed between the groups of different age and sex. CONCLUSIONS: Spongiform leucoencephalopathy after inhalation of heroin is a rare complication and has never been reported in mainland of China before. The lesions are symmetrical and spongiform, but not necrotic and the cerebellum is invariably involved--a feature consistent with the clinical presentation that begins with ataxia. Cerebral CT showed symmetrical non-enhancing hypodense areas in both cerebellar hemispheres. Cerebral MRI showed the corresponding areas with decreased signal intensity on T1 weighted images and increased signal intensity on T2 weighted images. There was no contrast enhancement. When it occurs, several cases are affected as a small epidemic. It is suggested that the aetiology is related to the heroin batch and could perhaps be a toxic effect of a substance which came from heroin pyrolysis.
Administration, Inhalation↗
Methane emission from a simulated rice field ecosystem as influenced by hydroquinone and dicyandiamide.
A simple apparatus for collecting methane emission from a simulated rice field ecosystem was formed. With no wheat straw powder amended all treatments with inhibitor(s) had so much lower methane emission during rice growth than the treatment with urea alone (control), which was contrary to methane emission from the cut rice-soil system. Especially for treatments with dicyandiamide (DCD) and with DCD plus hydroquinone (HQ), the total amount of methane emission from the soil system and intact rice-soil system was 68.25-46.64% and 46.89-41.78% of the control, respectively. Hence, DCD, especially in combination with HQ, not only increased methane oxidation in the floodwater-soil interface following application of urea, but also significantly enhanced methane oxidation in rice root rhizosphere, particularly from its tillering to booting stage. Wheat straw powder incorporated into flooded surface layer soil significantly weakened the above-mentioned simulating effects. Regression analysis indicated that methane emission from the rice field ecosystem was related to the turnover of ammonium-N in flooded surface layer soil. Diminishing methane emissions from the rice field ecosystem was significantly beneficial to the growth of rice.
Agriculture↗
Hepatocytes contribute to soluble CD14 production, and CD14 expression is differentially regulated in hepatocytes and monocytes.
CD14 presents as a glycosylphosphatidylinositol-linked membrane protein on the surface of monocytes/macrophages and as a soluble protein in the serum. Our previous studies have shown that an 80-kilobase pair (kb) genomic DNA fragment containing the human CD14 gene is sufficient to direct CD14 expression in a monocyte-specific manner in transgenic mice. In addition, we discovered that human CD14 is highly expressed in hepatocytes. Here, we report the generation of transgenic mice with either a 24- or 33-kb human CD14 genomic DNA fragment. Data from multiple transgenic lines show that neither the 24- nor the 33-kb transgenic mice express human CD14 in monocytes/macrophages. However, human CD14 is highly expressed in the liver of the 33-kb transgenic mice. These results demonstrate that human CD14 expression is regulated differently in monocytes and hepatocytes. Furthermore, we identified an upstream regulatory element beyond the 24-kb region, but within the 33-kb region of the human CD14 gene, which is critical for CD14 expression in hepatocytes, but not in monocytes/macrophages. Most importantly, the data demonstrate that the liver is one of the major organs for the production of soluble CD14. These transgenic mice provide an excellent system to further explore the functions of soluble CD14.
Animals↗
Polymorphisms of the DNA repair gene XRCC1 and risk of gastric cancer in a Chinese population.
Gastric cancer remains the leading cause of cancer death in China and other countries in eastern Asia. Studies of gastric cancer have revealed that it is a disease of complex etiology involving dietary, infectious, environmental, occupational and genetic factors. DNA repair capacity has been suggested as a genetic factor contributing to variation in susceptibility to cancer. In the present study, we described an association between 2 polymorphisms of the DNA repair gene XRCC1 and risk of gastric cancer in a Chinese population. We used a polymerase chain reaction-based assay to detect Pvu II and Nci I restriction fragment length polymorphisms (XRCC1 26304 C-->T and XRCC1 28152 G-->A, respectively) in 188 patients with gastric cancer and 166 healthy controls. The XRCC1 26304 T allele (194Trp) frequency (34.6%) was higher and the XRCC1 28152 A allele (399Gln) frequency (25.6%) was lower in healthy Chinese controls than previously reported healthy U.S. Caucasian controls (7.2% and 34.1%, respectively). Multivariate logistic regression analysis revealed that the putative high-risk genotypes XRCC1 26304 CC and XRCC1 28152 GA/AA were associated with a non-significant increased risk for gastric cancer (adjusted odds ratio [OR]=1.45, 95% confidence interval [CI]= 0.93-2.25 and OR=1.53, 95% CI= 0.98-2.39, respectively) compared with other genotypes. However, the XRCC1 26304 CC genotype was associated with a significantly increased risk for gastric cardia cancer (adjusted OR=1.86, 95% CI=1.09-3.20). Individuals with both putative high-risk genotypes (CC and GA/AA) had a significantly higher risk (adjusted OR=1.73, 95% CI=1.12-2.69), particularly for gastric cardia cancer (adjusted OR=2.18, 95% CI=1.21-3.94) than individuals with other genotypes. These findings support the hypothesis that these 2 XRCC1 variants may contribute to the risk of developing gastric cancer, particularly gastric cardia cancer.
Adult↗
Multichannel mode-filtered light detection based on an optical fiber for small-volume chemical analysis
A novel mode-filtered light detection method is described in which an unjacketed optical fiber is inserted into a transparent capillary tube and three or more detection channels are set on the capillary side for different distances from the port of the fiber. This new method is the basis of synchronization of separation and analysis, with which a modern multidimensional analysis apparatus will be constructed. For samples of different concentration, the more close to the laser incidence port of the fiber the detector has been set up, the greater the change of the intensity profile of mode-filtered light (deltaI(F)) that is obtained. Vice versa, if a parameter alpha = I0/In is established and, instead of a mode-filtered light signal, the reversed alteration trend of deltaalpha is found in comparison with the alteration trend of deltaI(F), the reason is that the background rapidly lowers with the increasing distance to the laser incidence port of the fiber; moreover, the mode-filtered light signal decreases slowly with it. With the present method and apparatus, glucose and glycerol have been determined, with good reproducibility and stability and a small sample volume. Furthermore, a real sample of glucose injection is measured for a detection volume of 5 microL, and an acceptable result is observed.
Journal Article↗
Analysis of the role of AML1-ETO in leukemogenesis, using an inducible transgenic mouse model.
As reported previously, AML1-ETO knock-in mice were generated to investigate the role of AML1-ETO in leukemogenesis and to mimic the progression of t(8;21) leukemia. These knock-in mice died in midgestation because of hemorrhaging in the central nervous system and a block of definitive hematopoiesis during embryogenesis. Therefore, they are not a good model system for the development of acute myeloid leukemia. Therefore, mice were generated in which the expression of AML1-ETO is under the control of a tetracycline-inducible system. Multiple lines of transgenic mice have been produced with the AML1-ETO complementary DNA controlled by a tetracycline-responsive element. In the absence of the antibiotic tetracycline, AML1-ETO is strongly expressed in the bone marrow of AML1-ETO and tet-controlled transcriptional activator double-positive transgenic mice. Furthermore, the addition of tetracycline reduces AML1-ETO expression in double-positive mice to nondetectable levels. Throughout the normal murine lifespan of 24 months, mice expressing AML1-ETO have not developed leukemia. In spite of this, abnormal maturation and proliferation of progenitor cells have been observed from these animals. These results demonstrate that AML1-ETO has a very restricted capacity to transform cells. Either the introduction of additional genetic changes or the expression of AML1-ETO at a particular stage of hematopoietic cell differentiation will be necessary to develop a model for studying the pathogenesis of t(8;21).
Acute Disease↗
Neuralized functions cell autonomously to regulate Drosophila sense organ development.
Neurogenic genes, including Notch and Delta, are thought to play important roles in regulating cell-cell interactions required for Drosophila sense organ development. To define the requirement of the neurogenic gene neuralized (neu) in this process, two independent neu alleles were used to generate mutant clones. We find that neu is required for determination of cell fates within the proneural cluster and that cells mutant for neu autonomously adopt neural fates when adjacent to wild-type cells. Furthermore, neu is required within the sense organ lineage to determine the fates of daughter cells and accessory cells. To gain insight into the mechanism by which neu functions, we used the GAL4/UAS system to express wild-type and epitope-tagged neu constructs. We show that Neu protein is localized primarily at the plasma membrane. We propose that the function of neu in sense organ development is to affect the ability of cells to receive Notch-Delta signals and thus modulate neurogenic activity that allows for the specification of non-neuronal cell fates in the sense organ.
Animals↗
Analysis of Arabidopsis glucose insensitive mutants, gin5 and gin6, reveals a central role of the plant hormone ABA in the regulation of plant vegetative development by sugar.
Sugars have signaling roles in a wide variety of developmental processes in plants. To elucidate the regulatory components that constitute the glucose signaling network governing plant growth and development, we have isolated and characterized two Arabidopsis glucose insensitive mutants, gin5 and gin6, based on a glucose-induced developmental arrest during early seedling morphogenesis. The T-DNA-tagged gin6 mutant abrogates the glucose-induced expression of a putative transcription factor, ABI4, previously shown to be involved in seed-specific abscisic acid (ABA) responses. Thus, ABI4 might be a regulator involved in both glucose- and seed-specific ABA signaling. The characterization of the gin5 mutant, on the other hand, reveals that glucose-specific accumulation of ABA is essential for hexokinase-mediated glucose responses. Consistent with this result, we show that three ABA-deficient mutants (aba1-1, aba2-1, and aba3-2) are also glucose insensitive. Exogenous ABA can restore normal glucose responses in gin5 and aba mutants but not in gin6 plants. Surprisingly, only abi4 and abi5-1 but not other ABA-insensitive signaling mutants (abi1-1, abi2-1, and abi3-1) exhibit glucose insensitivity, indicating the involvement of a distinct ABA signaling pathway in glucose responses. These results provide the first direct evidence to support a novel and central role of ABA in plant glucose responses mediated through glucose regulation of both ABA levels by GIN5 and ABA signaling by GIN6/ABI4.
Abscisic Acid↗
Deterin, a new inhibitor of apoptosis from Drosophila melanogaster.
Deterin, a new apoptosis inhibitor from Drosophila melanogaster, possesses an unusual structure of only a single baculovirus inhibitor of apoptosis (IAP)-type repeat and no RING finger motif. The biochemical actions of deterin are demonstrated in SF9 and S2 cell transfection assays, in which the expressed protein acts in the cytoplasm to inhibit or deter cells from apoptosis otherwise induced by the caspase-dependent apoptosis activator reaper or by cytotoxicants. A loss of function phenotype for deterin of cell death was indicated by transfections with either a dominant negative deterin mutant or with inhibitory RNA (RNAi) for deterin. The dominant negative C-terminal fragment that antagonized antiapoptotic activity of deterin did not affect antiapoptotic activity of DIAP1 or p35. Both the baculovirus IAP-type repeat (BIR) domain and the alpha-helical C-terminal domain are necessary in both SF9 and S2 cells for deterin to manifest its activity to prevent cell death. The approximately 650-base deterin transcript is present in embryos, third instar larvae, and late stage nurse cells of adult females. The deterin transcript is distributed throughout early stage embryos, whereas in later stage embryos it becomes progressively restricted to the central nervous system and gonads. Whereas the nematode survivin-type IAP has thus far been implicated only as a mitotic regulator, Drosophila deterin constitutes the first invertebrate member of the survivin-type IAP group to exhibit apoptosis-inhibitory activity.
Amino Acid Sequence↗
Crystal structure of the conserved core of protein arginine methyltransferase PRMT3.
Protein arginine methylation has been implicated in signal transduction, nuclear transport and transcription regulation. Protein arginine methyltransferases (PRMTs) mediate the AdoMet-dependent methylation of many proteins, including many RNA binding proteins involved in various aspects of RNA processing and/or transport. Here we describe the crystal structure of the rat PRMT3 catalytic core in complex with reaction product AdoHcy, determined at 2.0 A resolution. The results reveal a two-domain structure: an AdoMet-binding domain and a barrel-like domain. The AdoMet-binding domain is a compact version of the consensus AdoMet-dependent methyltransferase fold. The active site is situated in a cone-shaped pocket between the two domains. The residues that make up the active site are conserved across the PRMT family, consisting of a double-E loop containing two invariant Glu and one His-Asp proton-relay system. The structure suggests a mechanism for the methylation reaction and provides the structural basis for functional characterization of the PRMT family. In addition, crystal packing and solution behavior suggest dimer formation of the PRMT3 core.
Amino Acid Sequence↗
A branched DNA signal amplification assay to quantitate messenger RNA of human uncoupling proteins 1, 2, and 3.
Uncoupling proteins (UCP) are inner mitochondrial membrane transporters which dissipate the proton gradient, releasing stored energy as heat. Three subtypes of UCP have been identified so far. The regulation of UCP expression is mainly controlled at the transcriptional level, thus making the measurement of UCP mRNA beneficial for both diagnosis and research of weight disorders and diabetes. We have developed an assay using the branched DNA signal amplification assay (bDNA assay) to quantitatively measure the mRNA levels for human UCP1, 2, and 3. UCP-subtype-specific primers were designed for the assay. RNA transcripts of each UCP generated by in vitro transcription were used to validate the specificity and sensitivity of the assay. The quantitative measurement of UCP mRNA was further demonstrated with cultured cells and human tissue. A comprehensive survey of UCP expression from 17 human tissues measured by the newly developed assay is provided. The method described here offers a rapid, sensitive, specific, and quantitative assay for measurement of human UCP mRNA.
Adipocytes↗
Highly reduced protection against Streptococcus pneumoniae after deletion of a single heavy chain gene in mouse.
Phosphocholine (PC) is the immunodominant epitope found on the surface of Streptococcus pneumoniae (SPn). T15-idiotype Abs, whose heavy (H) chain variable region is encoded by the V1 gene, are dominant in the anti-PC response in adult mice and protect mice from lethal pneumococcal infection. The ability of anti-PC Abs using H chains other than the V1 H chain to protect against pneumococcal infection remains controversial. We generated V1(-/-) knockout mice to determine whether protective anti-PC Abs could be produced in the absence of the V1 gene. No anti-PC Abs were produced in V1(-/-) mice immunized with avirulent SPn; however, PC-BSA binding Abs were induced after immunization with PC-keyhole limpet hemocyanin but at significantly lower levels than those in wild-type mice. These Abs provided poor protection against virulent SPn; thus, <25% of V1(-/-) mice survived challenge with 10(4) bacteria as compared with 100% survival of V1(+/+) mice. The anti-PC Abs in V1(-/-) mice were heteroclitic, binding to nitrophenyl-PC better than to PC. None of nine hybridomas produced from V1(-/-) mice provided passive protection. However, the V1(-/-) mice produced normal amounts of Ab to SPn proteins that can partially protect mice against SPn. These data indicate that the V1 gene is critical for the production of anti-PC Abs providing optimum protection against infection with SPn, and the V1(-/-) mice could be useful in unmasking epitopes other than the immunodominant PC epitope on SPn capable of providing cross protection.
Animals↗
Detection of chemically induced DNA damage by derivative square wave voltammetry.
Damage of DNA films after reaction with styrene oxide was detected using derivative square wave voltammetry. Double-stranded (ds) DNA films with initially low backgrounds developed oxidation peaks for DNA bases during incubation with styrene oxide. Films were prepared on pyrolytic graphite (PG) electrodes by casting mixtures of DNA with the poly(ester sulfonic acid) ionomer Eastman AQ38S or by covalent binding of DNA onto oxidized PG. While both types of films gave oxidation peaks in the region 0.6-1.1 V vs SCE after incubations with styrene oxide, DNA/AQ films gave the best signal-to-background ratios. Damage of DNA by reaction with styrene oxide under the electrode incubation conditions was confirmed by capillary electrophoresis. Total integrals of oxidation peaks increased with time of incubation with styrene oxide. Relative peak heights depended on the type of DNA in the order calf thymus ds DNA > salmon sperm ds DNA > supercoiled ds DNA > highly polymerized calf thymus ds DNA.
Animals↗
Chiral capillary electrophoretic analysis of the enantiomeric purity of a pharmaceutical compound using sulfated beta-cyclodextrin.
A practical chiral capillary electrophoresis method using randomly sulfated beta-cyclodextrin was developed for the quantitative determination of the chiral purity of a pharmaceutical compound. A systematic method development approach was conducted by modifying selected parameters such as the concentration of the chiral selectors, buffer pH, organic modifiers, buffer concentrations and type, temperature and applied voltage. The results of the investigation permitted an improved understanding of the separation mechanism. Two facile strategies for the reversal of the enantiomer elution order are also described. The optimized method was validated in terms of variability of the chiral selector, linearity, sensitivity, accuracy, recovery, ruggedness, and precision.
Buffers↗