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Biomedical subjects

G Xie

Publications and source records attributed to G Xie.

72 records · Page 4Linked to original sources
PubMed1997

[Preparation of NADPH-cytochrome P-450 reductase and the role in metabolism of xenobiotics].

NADPH-Cytochrome P-450 Reductase is the major part of MFO (mixed function oxidase) system of liver. A simple and economic method of preparation of reductase was introduced in this paper and it was certified that xenobiotics benzene, bichloroethylene, and asbestos can be oxidized by reductase and reconstituted cytochrome P-450 2B1. But the metabolites of the 3 compounds can not cause the changes of plasmid PBR322 DNA.

Animals↗
PubMed1997

[The serum lipid and apolipoprotein levels of middle-aged male hyperlipidemics in Chengdu district].

It has been evidenced that cardiovascular diseases (CVD) relate with many risk factors and serum lipids play and essential role in the development of CVD. In order to further study hyperlipidemia (HL) in the middle-aged males, we analysed the body mass index (BMI), fast blood sugar (FBS), serum lipids and apolipoproteins A I, A II, B100, C II, C III and E in 223 male HL patients aged 41-60 and 349 normal male subjects who matched the HL patients in age. The result showed that the increase of serum triglycerids (TG), was as might be expected, the major characteristic of the middle-aged male HL patients in Chengdu District. Besides the serum lipid and apolipoprotein B100, C II, C III and E levels, the BMI and FBS levels in the IIb, IV and V types of HL patients were significantly higher than those in the normal subjects. It also showed that in TG increased patients the increased percentages of serum lipids were significantly higher than those of apolipoproteins. The age distribution in HL patients revealed that only 25% of the HL patients were between 41 to 50 years old, while 50% in the 56-60 year-old group. The relationship between apolipoprotein levels and serum lipid metabolism is also discussed. The results suggest that the 51-60 year-old males should pay attention to diet and increase physical activities to reduce incidence of HL which is directly associated with CVD.

Adult↗
PubMed1997

Analysis of tumor specific immunoglobulin gene rearrangement in peripheral blood B-cells of multiple myeloma patients by a PCR-SSCP method.

OBJECTIVE: To analyze the clonal relationship between lymphocytes in peripheral blood (PB) and myeloma cell in bone marrow (BM) for proving the existence of circulating tumor cells in multiple myeloma (MM) patients. METHODS: Eighteen patients with MM who have no cytomorphologic plasma cells and CyIg+ cells in PB demonstrated by anti-kappa and anti delta MoAbs using ABC method were involved in the present study, including 3 cases in phases I-II and 15 cases in phase III. The complementary determining region 3 (CDR3) of immunoglobulin heavy chain (IgH) gene was amplified by polymerase chain reaction (PCR). We further analysed the single strand conformation of the PCR products by single strand conformation polymorphism (SSCP) analysis to detect the mononuclear cells in PB and BM of the patients simultaneously. RESULTS: The same PCR products of IgH-CDR3 gene with BM samples were found in PB of 11 MM patients. The same PCR products and single strand conformation in both PB and BM were found in 9 cases. CONCLUSIONS: This study has proved the presence of identical clonal malignant cells in PB and BM of MM patients. B cells are involved in the pathogenesis of MM.

Adult↗
PubMed1997

Clinical study of desflurane on low flow anesthesia compared with sevoflurane and enflurane.

OBJECTIVE: To compare the hemodynamic change, course of recovery and adverse reaction in desflurane, sevoflurane and enflurane inhalation under low flow for patients undergoing selective abdominal surgery. METHODS: Following thiopental induction, 42 patients were divided into three groups: the first group received desflurane, the second sevoflurane and the third enflurane. During surgery, one of the agents around 1 minimum alveolar concentration (MAC) was used for maintenance, with fresh gas flow of 0.3-0.5 L/min for either desflurane or enflurane, and (0.8-1.0) L/min for sevoflurane. Heart rate (HR), blood pressure and end-tidal anesthetic concentration were monitored continuously. Time intervals from cutting off anesthetic to patient opening eyes, following commands, stating the time and location and recalling date of birth were all recorded. In addition, postoperative nausea or vomiting was traced. RESULTS: Desflurane caused the least cardiovascular depression. with mean arterial pressure (MAP) maintained significantly better at 10, 30 and 60 minutes of surgery and with HR stabilized right after incision as well. Its emergence was 2 times faster than sevoflurane, and 5-6 times quicker than enflurane. However, nausea or vomiting was found the lowest in patients receiving sevoflurane, though no distinct difference was shown between desflurane and enflurane. Nevertheless, patients under desflurane suffered less. CONCLUSIONS: Desflurane offers significant advantages for clinical anesthesia maintenance over sevoflurane and enflurane. It provides minimal cardiovascular depression, much quicker recovery, yet still causes some nausea during emergence.

Abdomen↗
PubMed1997

[Electromyogram (EMG) and muscle biopsy in patients with chronic spinal muscular atrophy].

The clinicopathological changes were investigated by electromyogram (EMG) and muscle biopsy in 30 cases of chronic spinal muscular atrophy. The results showed that the denervating changes were demonstrated in EMG in all patients but two. The light microscope discovered manifestation of neurogenic atrophy, and the electron microscope revealed a reduction of myofibrils, thickening and wavy appearance of Z-lines and dilation of mitochondria and endoplasmic reticula.

Adolescent↗
PubMed1996

Bisindolylmaleimides linked to DNA minor groove binding lexitropsins: synthesis, inhibitory activity against topoisomerase I, and biological evaluation.

The synthesis, characterization, inhibitory activity against topoisomerase I, and biological evaluation of a series of oligopeptide-substituted bisindolylmaleimides 7-12 are described. Compounds 7-9, which contain a basic C-terminus function such as (dimethylamino)propyl and bind to DNA with C(50) values of 200, 160, and 135 microM, respectively, exhibited inhibition of topoisomerase I in a concentration dependent manner. Also, the relative order of observed topoisomerase I inhibition is 9 > 8 > 7 at < or = 100 microM concentration, corresponding to the increase of the number of pyrrole units in the oligopeptide moiety. Compounds 10-12, which contain an electrostatically neutral moiety, such as methyl ester, did not bind to DNA templates nor inhibit topoisomerase I. However, the cytotoxicity activities of these compounds were 1.5 times greater than those of compounds 7-9.

Antineoplastic Agents↗
PubMed1996

pag-3, a Caenorhabditis elegans gene involved in touch neuron gene expression and coordinated movement.

Mutations in a newly identified gene, pag-3, cause ectopic expression of touch neuron genes meo-7, mec-7lacZ and mec-4lacZ in the lineal sisters of the ALM touch neurons, the BDU neurons. Pag-3 mutants also show a reverse kinker uncoordinated phenotype. The first pag-3 allele was isolated in a screen for mutants with altered immunofluorescence staining patterns. Two additional pag-3 alleles were identified in a noncomplementation screen of 38,000 haploid genomes. All of the pag-3 alleles were recessive to wild type and cause the same phenotypes. Two-factor crosses, deficiency mapping and three-factor crosses located pag-3 to the right arm of the X chromosome between unc-3 and unc-7. Because recessive mutations in pag-3 result in expression of several touch cell specific genes in the BDU neurons, pag-3(+) must directly or indirectly suppress expression of these genes in the BDU neurons. Although pag-3 mutants did not show mec-3lacZ expression in their BDU neurons, expression of mec-7lacZ and mec-4lacZ in the BDU neurons of pag-3 mutants required mec-3(+).

Alleles↗
PubMed1996

Novel DNA-directed alkylating agents consisting of naphthalimide, nitrogen mustard and lexitropsin moieties: synthesis, DNA sequence specificity and biological evaluation.

Novel DNA-directed alkylating agents comprising naphthalimide, nitrogen mustard and lexitropsin moieties have been designed, synthesized and characterized. Their properties have been evaluated with respect to DNA binding ability, sequence preference, influence of flanking sequences on alkylation efficiency and cytotoxic potency against KB human nasopharangeal tumour cells. The results indicate that, in contrast to distamycin and bis-benzimidazole-bearing nitrogen mustard moieties where DNA alkylation is directed to adenine N3 sites in the minor groove, the naphthalimide nitrogen mustards alkylate DNA at accessible guanine N7 sites within the major groove. Structural factors that may affect cytotoxic efficacy are discussed.

1-Naphthylamine↗
PubMed1996

[Experimental study and clinical application of primary choledochorraphy after choledochotomy].

An animal model was established in dogs to compare primary choledochorraphy with the traditional T-tube method. Authors observed cholangic histologic changes under microscope and electron-microscope between the two groups. The result showed that primary choledochorraphy was better than the traditional method. The advantage of primary choledochorraphy lies in its simplicity, safety and reliability, which have been shown in 30 patients of cholelithiasis in clinical application. It is suggested that for patients primary choledochorraphy may clesirably be used for patients who are indicated for this approach.

Adult↗
PubMed1995

Single-base sequencing and similarity comparisons.

A "single-base sequence" is a DNA sequence in which the identities and locations of bases of only one type have been determined. We present experimental procedures for single-base sequencing and describe the effective use of existing software (FASTA) in similarity comparisons of single-base sequences. We determined the theoretical and experimental minimum sequence lengths required for identification of a sequence within a large dataset and optimized the FASTA parameters for use in single-base similarity comparisons. Single-base sequences have been used to identify cDNAs occurring in a database. Single-base sequencing could be used to reduce the redundancy of "shot-gun sequencing."

Databases, Factual↗
PubMed1995

A C. elegans mutant screen based on antibody or histochemical staining.

A method has been developed for isolating mutations in Caenorhabditis elegans that alter antibody or histochemical staining patterns. The basis for this method is a new procedure for making C. elegans permeable that does not kill the eggs contained within the uterus of gravid adult hermaphrodites. A mutagenized population of gravid hermaphrodites is made permeable and then stained with either an antibody or a histochemical stain. Animals that stain aberrantly are picked to individual petri plates and the eggs within the uterus of the stained mother hatch and establish a new genetic line. Antibody and histochemical stains are especially useful phenotypes because the staining pattern will usually directly reflect the gene expression pattern of the gene that codes for the antigen or enzyme. This method was used to isolate mutants that alter the expression of a mec-7lacZ fusion gene. Transgenic animals that contained the mec-7lacZ gene integrated into chromosome I were treated with the mutagen ethylmethanesulfonate, allowed to self-fertilize for two generations and then stained with X-gal or antibodies against beta-galactosidase. Gravid animals that stained abnormally were picked to fresh petri plates and their offspring were used to establish new mutant lines.

Animals↗
PubMed1995

Design, synthesis, DNA sequence preferential alkylation and biological evaluation of N-mustard derivatives of distamycin and netropsin analogues.

The design and synthesis of certain oligopeptides structurally related to distamycin and netropsin, but bearing mixed heterocyclic moieties capable of recognizing alternative base sites and nitrogen mustard moieties capable of covalent binding to DNA, are described. The binding and thermally induced DNA cleavage, covalent interstrand cross-linking, DNA preferential alkylation and anticancer cytotoxicities of the new agents are described. In contrast to the mustard derivative derived directly from distamycin, the new agents give evidence of extensive DNA alkylation and interstrand cross-linking. In general, strong alkylation is observed at A residues for this class of agents, while the G residues that are alkylated appear to be more characteristic of individual compounds. Densitometric analysis of the frequency of bases adjacent to the alkylation sites (-3 to +3) revealed that the preferred bases are exclusively A/T with little preference shown for G bases and none for C sites. Further insight into the DNA alkylation processes afforded by the drugs was provided by an independent assay whereby heating the drug-DNA adduct with 10% aqueous piperidine only yielded strand breaks specifically at G-N7 sites in the major groove.

Alkylation↗
PubMed1994

Hybrid molecules containing propargylic sulfones and DNA minor groove-binding lexitropsins: synthesis, sequence specificity of reaction with DNA and biological evaluation.

A series of hybrids, 4-13, incorporating propargylic sulfones and minor groove-binding oligopeptide carriers, was synthesized. The anticipated preferential binding at adenine sites within the minor groove was confirmed by sequencing determination of these agents on high-resolution gels, indicating preferential alkylation at guanine, and significantly, high selectivity for 5'-GACG and 5'-GGTG. The ability of these hybrids to cleave DNA, as determined by agarose-gel assay, is consistent with the ethidium bromide fluorescence assay. The cytotoxicities of these compounds were also determined against human KB cells in vitro. Higher cytotoxic activities were observed for the compounds containing fewer N-methylpyrrole units, an imidazole group and a 2,3-disubstituted naphthyl moiety.

1-Propanol↗
PubMed1994

Comparison of three Knowledge Representation formalisms for encoding the NCEP Cholesterol Guidelines.

Although many Knowledge Representation (KR) formalisms have been used to encode care guidelines, there are few direct comparisons among different formalisms. In order to compare their suitability for encoding care guidelines, three different KR formalisms were used to encode the National Cholesterol Education Panel (NCEP) guideline. PROLOG, a First Order Logic system, CLASSIC, a frame-based representation system, and CLIPS, a production rule system, were used in the comparison. All three representations allowed accurate encoding of the guideline. PROLOG produced the most compact representation, but proved the most difficult to debug. The lack of arbitrary disjunction in CLASSIC greatly increased the complexity of the encoding. Overall, the CLIPS representation was the most intuitive and easiest to use.

Artificial Intelligence↗
PubMed1993

Effects of intermediate metabolites of 37 xenobiotics on the catalytic activities of reconstituted cytochrome P-450IIB1 and P-450IA1 enzyme systems.

Direct effects of intermediate metabolites of 37 different xenobiotics on the catalytic activities of both reconstituted cytochrome P-450IIB1 and P-450IA1 enzyme systems were studied by determination of NADPH oxidation at various intervals after initiation of the reaction. The results showed that cytochrome P-450IIB1 isozyme was much more likely than cytochrome P-450IA1 isozyme to be attacked by the reactive intermediates formed by some xenobiotics with smaller molecular weight and lose its catalytic activities. These xenobiotics were carbon tetrachloride, chloroform, carbon disulfide, benzene, parathion, methylparathion, methyldursban and dimethylnitrosamine. In contrast, however, steadily increasing metabolic activities were observed towards benzo(a)pyrene, 3-methylcholanthrene and polychlorinated biphenyls in reconstituted cytochrome P-450IA1 enzyme system as the reaction time prolonged within 4 min. The method discussed in this paper could be used as a simple and convenient way to observe directly the autocatalytic destruction of P-450 enzymes by some chemical agents.

Animals↗
PubMed1990

Tetrameric structure of mitochondrially bound rat brain hexokinase: a crosslinking study.

Rat brain hexokinase (ATP:D-hexose-6-phosphotransferase; EC 2.7.1.1) was derivatized with sulfosuccinimidyl-2-(m-azido-o-nitrobenzamido)ethyl-1,3'-dithiopro pionate (SAND), a photosensitive and cleavable crosslinking agent. The catalytic activity and mitochondrial binding properties of the enzyme were only marginally affected by reaction with SAND. When the derivatized enzyme was bound to liver mitochondria, photolysis resulted in extensive formation of a single crosslinked species with estimated molecular mass 460 kDa. This was determined to contain only hexokinase and thus represents a tetramer of the 116 kDa (apparent molecular mass in gel system used) monomeric enzyme. Although small amounts of tetramer were detected after photolysis of relatively high concentrations of derivatized enzyme in free solution, tetramer formation was greatly enhanced when the enzyme was bound to mitochondria. No evidence of dimeric or trimeric structures was seen even when only a small fraction of the available binding sites on the mitochondrial membrane were occupied. It is thus concluded that tetramer formation is closely linked with binding of the enzyme to the outer mitochondrial membrane and, more specifically, to the pore structure through which metabolites traverse this membrane. It is speculated that a tetrameric structure surrounding the mitochondrial pores may facilitate interactions between the hexokinase reaction and oxidative phosphorylation, mediated by the adenine nucleotides which are common intermediates in these reactions.

Animals↗
PubMedDate not supplied

Traditional Chinese medicine database and application on the Web.

To study traditional Chinese medicines and exchange related information through the worldwide Web, we developed a traditional Chinese medicine database and a program for searching and displaying data in the database on the Web. In this paper, the traditional Chinese medicine database is briefly introduced; the methods used in developing the program, including ISAPI (Microsoft Internet Server Application Programming Interface), VRML (Virtual Reality Model Language), and JavaScript are described; and three application examples are also given.

Databases, Factual↗